FM / Crypt

/usr/share/php/phpseclib/Crypt

Name	Size	Mode	Actions
AES.php	3704	0644	edit dl rm
Base.php	107555	0644	edit dl rm
Blowfish.php	26599	0644	edit dl rm
DES.php	71494	0644	edit dl rm
Hash.php	29308	0644	edit dl rm
Random.php	12327	0644	edit dl rm
RC2.php	22547	0644	edit dl rm
RC4.php	8757	0644	edit dl rm
Rijndael.php	41784	0644	edit dl rm
RSA.php	114169	0644	edit dl rm
TripleDES.php	13981	0644	edit dl rm
Twofish.php	37827	0644	edit dl rm

Edit: /usr/share/php/phpseclib/Crypt/RSA.php (114169B)

<?php

/**
 * Pure-PHP PKCS#1 (v2.1) compliant implementation of RSA.
 *
 * PHP version 5
 *
 * Here's an example of how to encrypt and decrypt text with this library:
 * <code>
 * <?php
 *    include 'phpseclib/autoload.php';
 *
 *    $rsa = new \phpseclib\Crypt\RSA();
 *    extract($rsa->createKey());
 *
 *    $plaintext = 'terrafrost';
 *
 *    $rsa->loadKey($privatekey);
 *    $ciphertext = $rsa->encrypt($plaintext);
 *
 *    $rsa->loadKey($publickey);
 *    echo $rsa->decrypt($ciphertext);
 * ?>
 * </code>
 *
 * Here's an example of how to create signatures and verify signatures with this library:
 * <code>
 * <?php
 *    include 'phpseclib/autoload.php';
 *
 *    $rsa = new \phpseclib\Crypt\RSA();
 *    extract($rsa->createKey());
 *
 *    $plaintext = 'terrafrost';
 *
 *    $rsa->loadKey($privatekey);
 *    $signature = $rsa->sign($plaintext);
 *
 *    $rsa->loadKey($publickey);
 *    echo $rsa->verify($plaintext, $signature) ? 'verified' : 'unverified';
 * ?>
 * </code>
 *
 * @category  Crypt
 * @package   RSA
 * @author    Jim Wigginton <terrafrost@php.net>
 * @copyright 2009 Jim Wigginton
 * @license   http://www.opensource.org/licenses/mit-license.html  MIT License
 * @link      http://phpseclib.sourceforge.net
 */

namespace phpseclib\Crypt;

use phpseclib\Math\BigInteger;

/**
 * Pure-PHP PKCS#1 compliant implementation of RSA.
 *
 * @package RSA
 * @author  Jim Wigginton <terrafrost@php.net>
 * @access  public
 */
class RSA
{
    /**#@+
     * @access public
     * @see self::encrypt()
     * @see self::decrypt()
     */
    /**
     * Use {@link http://en.wikipedia.org/wiki/Optimal_Asymmetric_Encryption_Padding Optimal Asymmetric Encryption Padding}
     * (OAEP) for encryption / decryption.
     *
     * Uses sha1 by default.
     *
     * @see self::setHash()
     * @see self::setMGFHash()
     */
    const ENCRYPTION_OAEP = 1;
    /**
     * Use PKCS#1 padding.
     *
     * Although self::ENCRYPTION_OAEP offers more security, including PKCS#1 padding is necessary for purposes of backwards
     * compatibility with protocols (like SSH-1) written before OAEP's introduction.
     */
    const ENCRYPTION_PKCS1 = 2;
    /**
     * Do not use any padding
     *
     * Although this method is not recommended it can none-the-less sometimes be useful if you're trying to decrypt some legacy
     * stuff, if you're trying to diagnose why an encrypted message isn't decrypting, etc.
     */
    const ENCRYPTION_NONE = 3;
    /**#@-*/

/**#@+
     * @access public
     * @see self::sign()
     * @see self::verify()
     * @see self::setHash()
    */
    /**
     * Use the Probabilistic Signature Scheme for signing
     *
     * Uses sha1 by default.
     *
     * @see self::setSaltLength()
     * @see self::setMGFHash()
     */
    const SIGNATURE_PSS = 1;
    /**
     * Use the PKCS#1 scheme by default.
     *
     * Although self::SIGNATURE_PSS offers more security, including PKCS#1 signing is necessary for purposes of backwards
     * compatibility with protocols (like SSH-2) written before PSS's introduction.
     */
    const SIGNATURE_PKCS1 = 2;
    /**#@-*/

/**#@+
     * @access private
     * @see \phpseclib\Crypt\RSA::createKey()
    */
    /**
     * ASN1 Integer
     */
    const ASN1_INTEGER = 2;
    /**
     * ASN1 Bit String
     */
    const ASN1_BITSTRING = 3;
    /**
     * ASN1 Octet String
     */
    const ASN1_OCTETSTRING = 4;
    /**
     * ASN1 Object Identifier
     */
    const ASN1_OBJECT = 6;
    /**
     * ASN1 Sequence (with the constucted bit set)
     */
    const ASN1_SEQUENCE = 48;
    /**#@-*/

/**#@+
     * @access private
     * @see \phpseclib\Crypt\RSA::__construct()
    */
    /**
     * To use the pure-PHP implementation
     */
    const MODE_INTERNAL = 1;
    /**
     * To use the OpenSSL library
     *
     * (if enabled; otherwise, the internal implementation will be used)
     */
    const MODE_OPENSSL = 2;
    /**#@-*/

/**#@+
     * @access public
     * @see \phpseclib\Crypt\RSA::createKey()
     * @see \phpseclib\Crypt\RSA::setPrivateKeyFormat()
    */
    /**
     * PKCS#1 formatted private key
     *
     * Used by OpenSSH
     */
    const PRIVATE_FORMAT_PKCS1 = 0;
    /**
     * PuTTY formatted private key
     */
    const PRIVATE_FORMAT_PUTTY = 1;
    /**
     * XML formatted private key
     */
    const PRIVATE_FORMAT_XML = 2;
    /**
     * PKCS#8 formatted private key
     */
    const PRIVATE_FORMAT_PKCS8 = 8;
    /**
     * OpenSSH formatted private key
     */
    const PRIVATE_FORMAT_OPENSSH = 9;
    /**#@-*/

/**#@+
     * @access public
     * @see \phpseclib\Crypt\RSA::createKey()
     * @see \phpseclib\Crypt\RSA::setPublicKeyFormat()
    */
    /**
     * Raw public key
     *
     * An array containing two \phpseclib\Math\BigInteger objects.
     *
     * The exponent can be indexed with any of the following:
     *
     * 0, e, exponent, publicExponent
     *
     * The modulus can be indexed with any of the following:
     *
     * 1, n, modulo, modulus
     */
    const PUBLIC_FORMAT_RAW = 3;
    /**
     * PKCS#1 formatted public key (raw)
     *
     * Used by File/X509.php
     *
     * Has the following header:
     *
     * -----BEGIN RSA PUBLIC KEY-----
     *
     * Analogous to ssh-keygen's pem format (as specified by -m)
     */
    const PUBLIC_FORMAT_PKCS1 = 4;
    const PUBLIC_FORMAT_PKCS1_RAW = 4;
    /**
     * XML formatted public key
     */
    const PUBLIC_FORMAT_XML = 5;
    /**
     * OpenSSH formatted public key
     *
     * Place in $HOME/.ssh/authorized_keys
     */
    const PUBLIC_FORMAT_OPENSSH = 6;
    /**
     * PKCS#1 formatted public key (encapsulated)
     *
     * Used by PHP's openssl_public_encrypt() and openssl's rsautl (when -pubin is set)
     *
     * Has the following header:
     *
     * -----BEGIN PUBLIC KEY-----
     *
     * Analogous to ssh-keygen's pkcs8 format (as specified by -m). Although PKCS8
     * is specific to private keys it's basically creating a DER-encoded wrapper
     * for keys. This just extends that same concept to public keys (much like ssh-keygen)
     */
    const PUBLIC_FORMAT_PKCS8 = 7;
    /**#@-*/

/**
     * Precomputed Zero
     *
     * @var \phpseclib\Math\BigInteger
     * @access private
     */
    var $zero;

/**
     * Precomputed One
     *
     * @var \phpseclib\Math\BigInteger
     * @access private
     */
    var $one;

/**
     * Private Key Format
     *
     * @var int
     * @access private
     */
    var $privateKeyFormat = self::PRIVATE_FORMAT_PKCS1;

/**
     * Public Key Format
     *
     * @var int
     * @access public
     */
    var $publicKeyFormat = self::PUBLIC_FORMAT_PKCS8;

/**
     * Modulus (ie. n)
     *
     * @var \phpseclib\Math\BigInteger
     * @access private
     */
    var $modulus;

/**
     * Modulus length
     *
     * @var \phpseclib\Math\BigInteger
     * @access private
     */
    var $k;

/**
     * Exponent (ie. e or d)
     *
     * @var \phpseclib\Math\BigInteger
     * @access private
     */
    var $exponent;

/**
     * Primes for Chinese Remainder Theorem (ie. p and q)
     *
     * @var array
     * @access private
     */
    var $primes;

/**
     * Exponents for Chinese Remainder Theorem (ie. dP and dQ)
     *
     * @var array
     * @access private
     */
    var $exponents;

/**
     * Coefficients for Chinese Remainder Theorem (ie. qInv)
     *
     * @var array
     * @access private
     */
    var $coefficients;

/**
     * Hash name
     *
     * @var string
     * @access private
     */
    var $hashName;

/**
     * Hash function
     *
     * @var \phpseclib\Crypt\Hash
     * @access private
     */
    var $hash;

/**
     * Length of hash function output
     *
     * @var int
     * @access private
     */
    var $hLen;

/**
     * Length of salt
     *
     * @var int
     * @access private
     */
    var $sLen;

/**
     * Hash function for the Mask Generation Function
     *
     * @var \phpseclib\Crypt\Hash
     * @access private
     */
    var $mgfHash;

/**
     * Length of MGF hash function output
     *
     * @var int
     * @access private
     */
    var $mgfHLen;

/**
     * Encryption mode
     *
     * @var int
     * @access private
     */
    var $encryptionMode = self::ENCRYPTION_OAEP;

/**
     * Signature mode
     *
     * @var int
     * @access private
     */
    var $signatureMode = self::SIGNATURE_PSS;

/**
     * Public Exponent
     *
     * @var mixed
     * @access private
     */
    var $publicExponent = false;

/**
     * Password
     *
     * @var string
     * @access private
     */
    var $password = false;

/**
     * Components
     *
     * For use with parsing XML formatted keys.  PHP's XML Parser functions use utilized - instead of PHP's DOM functions -
     * because PHP's XML Parser functions work on PHP4 whereas PHP's DOM functions - although surperior - don't.
     *
     * @see self::_start_element_handler()
     * @var array
     * @access private
     */
    var $components = array();

/**
     * Current String
     *
     * For use with parsing XML formatted keys.
     *
     * @see self::_character_handler()
     * @see self::_stop_element_handler()
     * @var mixed
     * @access private
     */
    var $current;

/**
     * OpenSSL configuration file name.
     *
     * Set to null to use system configuration file.
     * @see self::createKey()
     * @var mixed
     * @Access public
     */
    var $configFile;

/**
     * Public key comment field.
     *
     * @var string
     * @access private
     */
    var $comment = 'phpseclib-generated-key';

/**
     * The constructor
     *
     * If you want to make use of the openssl extension, you'll need to set the mode manually, yourself.  The reason
     * \phpseclib\Crypt\RSA doesn't do it is because OpenSSL doesn't fail gracefully.  openssl_pkey_new(), in particular, requires
     * openssl.cnf be present somewhere and, unfortunately, the only real way to find out is too late.
     *
     * @return \phpseclib\Crypt\RSA
     * @access public
     */
    function __construct()
    {
        $this->configFile = dirname(__FILE__) . '/../openssl.cnf';

if (!defined('CRYPT_RSA_MODE')) {
            switch (true) {
                // Math/BigInteger's openssl requirements are a little less stringent than Crypt/RSA's. in particular,
                // Math/BigInteger doesn't require an openssl.cfg file whereas Crypt/RSA does. so if Math/BigInteger
                // can't use OpenSSL it can be pretty trivially assumed, then, that Crypt/RSA can't either.
                case defined('MATH_BIGINTEGER_OPENSSL_DISABLE'):
                    define('CRYPT_RSA_MODE', self::MODE_INTERNAL);
                    break;
                case function_exists('phpinfo') && extension_loaded('openssl') && file_exists($this->configFile):
                    // some versions of XAMPP have mismatched versions of OpenSSL which causes it not to work
                    $versions = array();

// avoid generating errors (even with suppression) when phpinfo() is disabled (common in production systems)
                    if (strpos(ini_get('disable_functions'), 'phpinfo') === false) {
                        ob_start();
                        @phpinfo();
                        $content = ob_get_contents();
                        ob_end_clean();

preg_match_all('#OpenSSL (Header|Library) Version(.*)#im', $content, $matches);

if (!empty($matches[1])) {
                            for ($i = 0; $i < count($matches[1]); $i++) {
                                $fullVersion = trim(str_replace('=>', '', strip_tags($matches[2][$i])));

// Remove letter part in OpenSSL version
                                if (!preg_match('/(\d+\.\d+\.\d+)/i', $fullVersion, $m)) {
                                    $versions[$matches[1][$i]] = $fullVersion;
                                } else {
                                    $versions[$matches[1][$i]] = $m[0];
                                }
                            }
                        }
                    }

// it doesn't appear that OpenSSL versions were reported upon until PHP 5.3+
                    switch (true) {
                        case !isset($versions['Header']):
                        case !isset($versions['Library']):
                        case $versions['Header'] == $versions['Library']:
                        case version_compare($versions['Header'], '1.0.0') >= 0 && version_compare($versions['Library'], '1.0.0') >= 0:
                            define('CRYPT_RSA_MODE', self::MODE_OPENSSL);
                            break;
                        default:
                            define('CRYPT_RSA_MODE', self::MODE_INTERNAL);
                            define('MATH_BIGINTEGER_OPENSSL_DISABLE', true);
                    }
                    break;
                default:
                    define('CRYPT_RSA_MODE', self::MODE_INTERNAL);
            }
        }

$this->zero = new BigInteger();
        $this->one = new BigInteger(1);

$this->hash = new Hash('sha1');
        $this->hLen = $this->hash->getLength();
        $this->hashName = 'sha1';
        $this->mgfHash = new Hash('sha1');
        $this->mgfHLen = $this->mgfHash->getLength();
    }

/**
     * Create public / private key pair
     *
     * Returns an array with the following three elements:
     *  - 'privatekey': The private key.
     *  - 'publickey':  The public key.
     *  - 'partialkey': A partially computed key (if the execution time exceeded $timeout).
     *                  Will need to be passed back to \phpseclib\Crypt\RSA::createKey() as the third parameter for further processing.
     *
     * @access public
     * @param int $bits
     * @param int $timeout
     * @param array $partial
     */
    function createKey($bits = 1024, $timeout = false, $partial = array())
    {
        if (!defined('CRYPT_RSA_EXPONENT')) {
            // http://en.wikipedia.org/wiki/65537_%28number%29
            define('CRYPT_RSA_EXPONENT', '65537');
        }
        // per <http://cseweb.ucsd.edu/~hovav/dist/survey.pdf#page=5>, this number ought not result in primes smaller
        // than 256 bits. as a consequence if the key you're trying to create is 1024 bits and you've set CRYPT_RSA_SMALLEST_PRIME
        // to 384 bits then you're going to get a 384 bit prime and a 640 bit prime (384 + 1024 % 384). at least if
        // CRYPT_RSA_MODE is set to self::MODE_INTERNAL. if CRYPT_RSA_MODE is set to self::MODE_OPENSSL then
        // CRYPT_RSA_SMALLEST_PRIME is ignored (ie. multi-prime RSA support is more intended as a way to speed up RSA key
        // generation when there's a chance neither gmp nor OpenSSL are installed)
        if (!defined('CRYPT_RSA_SMALLEST_PRIME')) {
            define('CRYPT_RSA_SMALLEST_PRIME', 4096);
        }

// OpenSSL uses 65537 as the exponent and requires RSA keys be 384 bits minimum
        if (CRYPT_RSA_MODE == self::MODE_OPENSSL && $bits >= 384 && CRYPT_RSA_EXPONENT == 65537) {
            $config = array();
            if (isset($this->configFile)) {
                $config['config'] = $this->configFile;
            }
            $rsa = openssl_pkey_new(array('private_key_bits' => $bits) + $config);
            openssl_pkey_export($rsa, $privatekey, null, $config);
            $publickey = openssl_pkey_get_details($rsa);
            $publickey = $publickey['key'];

$privatekey = call_user_func_array(array($this, '_convertPrivateKey'), array_values($this->_parseKey($privatekey, self::PRIVATE_FORMAT_PKCS1)));
            $publickey = call_user_func_array(array($this, '_convertPublicKey'), array_values($this->_parseKey($publickey, self::PUBLIC_FORMAT_PKCS1)));

// clear the buffer of error strings stemming from a minimalistic openssl.cnf
            while (openssl_error_string() !== false) {
            }

return array(
                'privatekey' => $privatekey,
                'publickey' => $publickey,
                'partialkey' => false
            );
        }

static $e;
        if (!isset($e)) {
            $e = new BigInteger(CRYPT_RSA_EXPONENT);
        }

extract($this->_generateMinMax($bits));
        $absoluteMin = $min;
        $temp = $bits >> 1; // divide by two to see how many bits P and Q would be
        if ($temp > CRYPT_RSA_SMALLEST_PRIME) {
            $num_primes = floor($bits / CRYPT_RSA_SMALLEST_PRIME);
            $temp = CRYPT_RSA_SMALLEST_PRIME;
        } else {
            $num_primes = 2;
        }
        extract($this->_generateMinMax($temp + $bits % $temp));
        $finalMax = $max;
        extract($this->_generateMinMax($temp));

$generator = new BigInteger();

$n = $this->one->copy();
        if (!empty($partial)) {
            extract(unserialize($partial));
        } else {
            $exponents = $coefficients = $primes = array();
            $lcm = array(
                'top' => $this->one->copy(),
                'bottom' => false
            );
        }

$start = time();
        $i0 = count($primes) + 1;

do {
            for ($i = $i0; $i <= $num_primes; $i++) {
                if ($timeout !== false) {
                    $timeout-= time() - $start;
                    $start = time();
                    if ($timeout <= 0) {
                        return array(
                            'privatekey' => '',
                            'publickey'  => '',
                            'partialkey' => serialize(array(
                                'primes' => $primes,
                                'coefficients' => $coefficients,
                                'lcm' => $lcm,
                                'exponents' => $exponents
                            ))
                        );
                    }
                }

if ($i == $num_primes) {
                    list($min, $temp) = $absoluteMin->divide($n);
                    if (!$temp->equals($this->zero)) {
                        $min = $min->add($this->one); // ie. ceil()
                    }
                    $primes[$i] = $generator->randomPrime($min, $finalMax, $timeout);
                } else {
                    $primes[$i] = $generator->randomPrime($min, $max, $timeout);
                }

if ($primes[$i] === false) { // if we've reached the timeout
                    if (count($primes) > 1) {
                        $partialkey = '';
                    } else {
                        array_pop($primes);
                        $partialkey = serialize(array(
                            'primes' => $primes,
                            'coefficients' => $coefficients,
                            'lcm' => $lcm,
                            'exponents' => $exponents
                        ));
                    }

return array(
                        'privatekey' => '',
                        'publickey'  => '',
                        'partialkey' => $partialkey
                    );
                }

// the first coefficient is calculated differently from the rest
                // ie. instead of being $primes[1]->modInverse($primes[2]), it's $primes[2]->modInverse($primes[1])
                if ($i > 2) {
                    $coefficients[$i] = $n->modInverse($primes[$i]);
                }

$n = $n->multiply($primes[$i]);

$temp = $primes[$i]->subtract($this->one);

// textbook RSA implementations use Euler's totient function instead of the least common multiple.
                // see http://en.wikipedia.org/wiki/Euler%27s_totient_function
                $lcm['top'] = $lcm['top']->multiply($temp);
                $lcm['bottom'] = $lcm['bottom'] === false ? $temp : $lcm['bottom']->gcd($temp);

$exponents[$i] = $e->modInverse($temp);
            }

list($temp) = $lcm['top']->divide($lcm['bottom']);
            $gcd = $temp->gcd($e);
            $i0 = 1;
        } while (!$gcd->equals($this->one));

$d = $e->modInverse($temp);

$coefficients[2] = $primes[2]->modInverse($primes[1]);

// from <http://tools.ietf.org/html/rfc3447#appendix-A.1.2>:
        // RSAPrivateKey ::= SEQUENCE {
        //     version           Version,
        //     modulus           INTEGER,  -- n
        //     publicExponent    INTEGER,  -- e
        //     privateExponent   INTEGER,  -- d
        //     prime1            INTEGER,  -- p
        //     prime2            INTEGER,  -- q
        //     exponent1         INTEGER,  -- d mod (p-1)
        //     exponent2         INTEGER,  -- d mod (q-1)
        //     coefficient       INTEGER,  -- (inverse of q) mod p
        //     otherPrimeInfos   OtherPrimeInfos OPTIONAL
        // }

return array(
            'privatekey' => $this->_convertPrivateKey($n, $e, $d, $primes, $exponents, $coefficients),
            'publickey'  => $this->_convertPublicKey($n, $e),
            'partialkey' => false
        );
    }

/**
     * Convert a private key to the appropriate format.
     *
     * @access private
     * @see self::setPrivateKeyFormat()
     * @param Math_BigInteger $n
     * @param Math_BigInteger $e
     * @param Math_BigInteger $d
     * @param array<int,Math_BigInteger> $primes
     * @param array<int,Math_BigInteger> $exponents
     * @param array<int,Math_BigInteger> $coefficients
     * @return string
     */
    function _convertPrivateKey($n, $e, $d, $primes, $exponents, $coefficients)
    {
        $signed = $this->privateKeyFormat != self::PRIVATE_FORMAT_XML;
        $num_primes = count($primes);
        $raw = array(
            'version' => $num_primes == 2 ? chr(0) : chr(1), // two-prime vs. multi
            'modulus' => $n->toBytes($signed),
            'publicExponent' => $e->toBytes($signed),
            'privateExponent' => $d->toBytes($signed),
            'prime1' => $primes[1]->toBytes($signed),
            'prime2' => $primes[2]->toBytes($signed),
            'exponent1' => $exponents[1]->toBytes($signed),
            'exponent2' => $exponents[2]->toBytes($signed),
            'coefficient' => $coefficients[2]->toBytes($signed)
        );

// if the format in question does not support multi-prime rsa and multi-prime rsa was used,
        // call _convertPublicKey() instead.
        switch ($this->privateKeyFormat) {
            case self::PRIVATE_FORMAT_XML:
                if ($num_primes != 2) {
                    return false;
                }
                return "<RSAKeyValue>\r\n" .
                       '  <Modulus>' . base64_encode($raw['modulus']) . "</Modulus>\r\n" .
                       '  <Exponent>' . base64_encode($raw['publicExponent']) . "</Exponent>\r\n" .
                       '  <P>' . base64_encode($raw['prime1']) . "</P>\r\n" .
                       '  <Q>' . base64_encode($raw['prime2']) . "</Q>\r\n" .
                       '  <DP>' . base64_encode($raw['exponent1']) . "</DP>\r\n" .
                       '  <DQ>' . base64_encode($raw['exponent2']) . "</DQ>\r\n" .
                       '  <InverseQ>' . base64_encode($raw['coefficient']) . "</InverseQ>\r\n" .
                       '  <D>' . base64_encode($raw['privateExponent']) . "</D>\r\n" .
                       '</RSAKeyValue>';
                break;
            case self::PRIVATE_FORMAT_PUTTY:
                if ($num_primes != 2) {
                    return false;
                }
                $key = "PuTTY-User-Key-File-2: ssh-rsa\r\nEncryption: ";
                $encryption = (!empty($this->password) || is_string($this->password)) ? 'aes256-cbc' : 'none';
                $key.= $encryption;
                $key.= "\r\nComment: " . $this->comment . "\r\n";
                $public = pack(
                    'Na*Na*Na*',
                    strlen('ssh-rsa'),
                    'ssh-rsa',
                    strlen($raw['publicExponent']),
                    $raw['publicExponent'],
                    strlen($raw['modulus']),
                    $raw['modulus']
                );
                $source = pack(
                    'Na*Na*Na*Na*',
                    strlen('ssh-rsa'),
                    'ssh-rsa',
                    strlen($encryption),
                    $encryption,
                    strlen($this->comment),
                    $this->comment,
                    strlen($public),
                    $public
                );
                $public = base64_encode($public);
                $key.= "Public-Lines: " . ((strlen($public) + 63) >> 6) . "\r\n";
                $key.= chunk_split($public, 64);
                $private = pack(
                    'Na*Na*Na*Na*',
                    strlen($raw['privateExponent']),
                    $raw['privateExponent'],
                    strlen($raw['prime1']),
                    $raw['prime1'],
                    strlen($raw['prime2']),
                    $raw['prime2'],
                    strlen($raw['coefficient']),
                    $raw['coefficient']
                );
                if (empty($this->password) && !is_string($this->password)) {
                    $source.= pack('Na*', strlen($private), $private);
                    $hashkey = 'putty-private-key-file-mac-key';
                } else {
                    $private.= Random::string(16 - (strlen($private) & 15));
                    $source.= pack('Na*', strlen($private), $private);
                    $sequence = 0;
                    $symkey = '';
                    while (strlen($symkey) < 32) {
                        $temp = pack('Na*', $sequence++, $this->password);
                        $symkey.= pack('H*', sha1($temp));
                    }
                    $symkey = substr($symkey, 0, 32);
                    $crypto = new AES();

$crypto->setKey($symkey);
                    $crypto->disablePadding();
                    $private = $crypto->encrypt($private);
                    $hashkey = 'putty-private-key-file-mac-key' . $this->password;
                }

$private = base64_encode($private);
                $key.= 'Private-Lines: ' . ((strlen($private) + 63) >> 6) . "\r\n";
                $key.= chunk_split($private, 64);
                $hash = new Hash('sha1');
                $hash->setKey(pack('H*', sha1($hashkey)));
                $key.= 'Private-MAC: ' . bin2hex($hash->hash($source)) . "\r\n";

return $key;
            case self::PRIVATE_FORMAT_OPENSSH:
                if ($num_primes != 2) {
                    return false;
                }
                $publicKey = pack('Na*Na*Na*', strlen('ssh-rsa'), 'ssh-rsa', strlen($raw['publicExponent']), $raw['publicExponent'], strlen($raw['modulus']), $raw['modulus']);
                $privateKey = pack(
                    'Na*Na*Na*Na*Na*Na*Na*',
                    strlen('ssh-rsa'),
                    'ssh-rsa',
                    strlen($raw['modulus']),
                    $raw['modulus'],
                    strlen($raw['publicExponent']),
                    $raw['publicExponent'],
                    strlen($raw['privateExponent']),
                    $raw['privateExponent'],
                    strlen($raw['coefficient']),
                    $raw['coefficient'],
                    strlen($raw['prime1']),
                    $raw['prime1'],
                    strlen($raw['prime2']),
                    $raw['prime2']
                );
                $checkint = Random::string(4);
                $paddedKey = pack(
                    'a*Na*',
                    $checkint . $checkint . $privateKey,
                    strlen($this->comment),
                    $this->comment
                );
                $paddingLength = (7 * strlen($paddedKey)) % 8;
                for ($i = 1; $i <= $paddingLength; $i++) {
                    $paddedKey.= chr($i);
                }
                $key = pack(
                    'Na*Na*Na*NNa*Na*',
                    strlen('none'),
                    'none',
                    strlen('none'),
                    'none',
                    0,
                    '',
                    1,
                    strlen($publicKey),
                    $publicKey,
                    strlen($paddedKey),
                    $paddedKey
                );
                $key = "openssh-key-v1\0$key";

return "-----BEGIN OPENSSH PRIVATE KEY-----\n" .
                       chunk_split(base64_encode($key), 70, "\n") .
                       "-----END OPENSSH PRIVATE KEY-----\n";
            default: // eg. self::PRIVATE_FORMAT_PKCS1
                $components = array();
                foreach ($raw as $name => $value) {
                    $components[$name] = pack('Ca*a*', self::ASN1_INTEGER, $this->_encodeLength(strlen($value)), $value);
                }

$RSAPrivateKey = implode('', $components);

if ($num_primes > 2) {
                    $OtherPrimeInfos = '';
                    for ($i = 3; $i <= $num_primes; $i++) {
                        // OtherPrimeInfos ::= SEQUENCE SIZE(1..MAX) OF OtherPrimeInfo
                        //
                        // OtherPrimeInfo ::= SEQUENCE {
                        //     prime             INTEGER,  -- ri
                        //     exponent          INTEGER,  -- di
                        //     coefficient       INTEGER   -- ti
                        // }
                        $OtherPrimeInfo = pack('Ca*a*', self::ASN1_INTEGER, $this->_encodeLength(strlen($primes[$i]->toBytes(true))), $primes[$i]->toBytes(true));
                        $OtherPrimeInfo.= pack('Ca*a*', self::ASN1_INTEGER, $this->_encodeLength(strlen($exponents[$i]->toBytes(true))), $exponents[$i]->toBytes(true));
                        $OtherPrimeInfo.= pack('Ca*a*', self::ASN1_INTEGER, $this->_encodeLength(strlen($coefficients[$i]->toBytes(true))), $coefficients[$i]->toBytes(true));
                        $OtherPrimeInfos.= pack('Ca*a*', self::ASN1_SEQUENCE, $this->_encodeLength(strlen($OtherPrimeInfo)), $OtherPrimeInfo);
                    }
                    $RSAPrivateKey.= pack('Ca*a*', self::ASN1_SEQUENCE, $this->_encodeLength(strlen($OtherPrimeInfos)), $OtherPrimeInfos);
                }

$RSAPrivateKey = pack('Ca*a*', self::ASN1_SEQUENCE, $this->_encodeLength(strlen($RSAPrivateKey)), $RSAPrivateKey);

if ($this->privateKeyFormat == self::PRIVATE_FORMAT_PKCS8) {
                    $rsaOID = pack('H*', '300d06092a864886f70d0101010500'); // hex version of MA0GCSqGSIb3DQEBAQUA
                    $RSAPrivateKey = pack(
                        'Ca*a*Ca*a*',
                        self::ASN1_INTEGER,
                        "\01\00",
                        $rsaOID,
                        4,
                        $this->_encodeLength(strlen($RSAPrivateKey)),
                        $RSAPrivateKey
                    );
                    $RSAPrivateKey = pack('Ca*a*', self::ASN1_SEQUENCE, $this->_encodeLength(strlen($RSAPrivateKey)), $RSAPrivateKey);
                    if (!empty($this->password) || is_string($this->password)) {
                        $salt = Random::string(8);
                        $iterationCount = 2048;

$crypto = new DES();
                        $crypto->setPassword($this->password, 'pbkdf1', 'md5', $salt, $iterationCount);
                        $RSAPrivateKey = $crypto->encrypt($RSAPrivateKey);

$parameters = pack(
                            'Ca*a*Ca*N',
                            self::ASN1_OCTETSTRING,
                            $this->_encodeLength(strlen($salt)),
                            $salt,
                            self::ASN1_INTEGER,
                            $this->_encodeLength(4),
                            $iterationCount
                        );
                        $pbeWithMD5AndDES_CBC = "\x2a\x86\x48\x86\xf7\x0d\x01\x05\x03";

$encryptionAlgorithm = pack(
                            'Ca*a*Ca*a*',
                            self::ASN1_OBJECT,
                            $this->_encodeLength(strlen($pbeWithMD5AndDES_CBC)),
                            $pbeWithMD5AndDES_CBC,
                            self::ASN1_SEQUENCE,
                            $this->_encodeLength(strlen($parameters)),
                            $parameters
                        );

$RSAPrivateKey = pack(
                            'Ca*a*Ca*a*',
                            self::ASN1_SEQUENCE,
                            $this->_encodeLength(strlen($encryptionAlgorithm)),
                            $encryptionAlgorithm,
                            self::ASN1_OCTETSTRING,
                            $this->_encodeLength(strlen($RSAPrivateKey)),
                            $RSAPrivateKey
                        );

$RSAPrivateKey = pack('Ca*a*', self::ASN1_SEQUENCE, $this->_encodeLength(strlen($RSAPrivateKey)), $RSAPrivateKey);

$RSAPrivateKey = "-----BEGIN ENCRYPTED PRIVATE KEY-----\r\n" .
                                         chunk_split(base64_encode($RSAPrivateKey), 64) .
                                         '-----END ENCRYPTED PRIVATE KEY-----';
                    } else {
                        $RSAPrivateKey = "-----BEGIN PRIVATE KEY-----\r\n" .
                                         chunk_split(base64_encode($RSAPrivateKey), 64) .
                                         '-----END PRIVATE KEY-----';
                    }
                    return $RSAPrivateKey;
                }

if (!empty($this->password) || is_string($this->password)) {
                    $iv = Random::string(8);
                    $symkey = pack('H*', md5($this->password . $iv)); // symkey is short for symmetric key
                    $symkey.= substr(pack('H*', md5($symkey . $this->password . $iv)), 0, 8);
                    $des = new TripleDES();
                    $des->setKey($symkey);
                    $des->setIV($iv);
                    $iv = strtoupper(bin2hex($iv));
                    $RSAPrivateKey = "-----BEGIN RSA PRIVATE KEY-----\r\n" .
                                     "Proc-Type: 4,ENCRYPTED\r\n" .
                                     "DEK-Info: DES-EDE3-CBC,$iv\r\n" .
                                     "\r\n" .
                                     chunk_split(base64_encode($des->encrypt($RSAPrivateKey)), 64) .
                                     '-----END RSA PRIVATE KEY-----';
                } else {
                    $RSAPrivateKey = "-----BEGIN RSA PRIVATE KEY-----\r\n" .
                                     chunk_split(base64_encode($RSAPrivateKey), 64) .
                                     '-----END RSA PRIVATE KEY-----';
                }

return $RSAPrivateKey;
        }
    }

/**
     * Convert a public key to the appropriate format
     *
     * @access private
     * @see self::setPublicKeyFormat()
     * @param Math_BigInteger $n
     * @param Math_BigInteger $e
     * @return string|array<string,Math_BigInteger>
     */
    function _convertPublicKey($n, $e)
    {
        $signed = $this->publicKeyFormat != self::PUBLIC_FORMAT_XML;

$modulus = $n->toBytes($signed);
        $publicExponent = $e->toBytes($signed);

switch ($this->publicKeyFormat) {
            case self::PUBLIC_FORMAT_RAW:
                return array('e' => $e->copy(), 'n' => $n->copy());
            case self::PUBLIC_FORMAT_XML:
                return "<RSAKeyValue>\r\n" .
                       '  <Modulus>' . base64_encode($modulus) . "</Modulus>\r\n" .
                       '  <Exponent>' . base64_encode($publicExponent) . "</Exponent>\r\n" .
                       '</RSAKeyValue>';
                break;
            case self::PUBLIC_FORMAT_OPENSSH:
                // from <http://tools.ietf.org/html/rfc4253#page-15>:
                // string    "ssh-rsa"
                // mpint     e
                // mpint     n
                $RSAPublicKey = pack('Na*Na*Na*', strlen('ssh-rsa'), 'ssh-rsa', strlen($publicExponent), $publicExponent, strlen($modulus), $modulus);
                $RSAPublicKey = 'ssh-rsa ' . base64_encode($RSAPublicKey) . ' ' . $this->comment;

return $RSAPublicKey;
            default: // eg. self::PUBLIC_FORMAT_PKCS1_RAW or self::PUBLIC_FORMAT_PKCS1
                // from <http://tools.ietf.org/html/rfc3447#appendix-A.1.1>:
                // RSAPublicKey ::= SEQUENCE {
                //     modulus           INTEGER,  -- n
                //     publicExponent    INTEGER   -- e
                // }
                $components = array(
                    'modulus' => pack('Ca*a*', self::ASN1_INTEGER, $this->_encodeLength(strlen($modulus)), $modulus),
                    'publicExponent' => pack('Ca*a*', self::ASN1_INTEGER, $this->_encodeLength(strlen($publicExponent)), $publicExponent)
                );

$RSAPublicKey = pack(
                    'Ca*a*a*',
                    self::ASN1_SEQUENCE,
                    $this->_encodeLength(strlen($components['modulus']) + strlen($components['publicExponent'])),
                    $components['modulus'],
                    $components['publicExponent']
                );

if ($this->publicKeyFormat == self::PUBLIC_FORMAT_PKCS1_RAW) {
                    $RSAPublicKey = "-----BEGIN RSA PUBLIC KEY-----\r\n" .
                                    chunk_split(base64_encode($RSAPublicKey), 64) .
                                    '-----END RSA PUBLIC KEY-----';
                } else {
                    // sequence(oid(1.2.840.113549.1.1.1), null)) = rsaEncryption.
                    $rsaOID = pack('H*', '300d06092a864886f70d0101010500'); // hex version of MA0GCSqGSIb3DQEBAQUA
                    $RSAPublicKey = chr(0) . $RSAPublicKey;
                    $RSAPublicKey = chr(3) . $this->_encodeLength(strlen($RSAPublicKey)) . $RSAPublicKey;

$RSAPublicKey = pack(
                        'Ca*a*',
                        self::ASN1_SEQUENCE,
                        $this->_encodeLength(strlen($rsaOID . $RSAPublicKey)),
                        $rsaOID . $RSAPublicKey
                    );

$RSAPublicKey = "-----BEGIN PUBLIC KEY-----\r\n" .
                                     chunk_split(base64_encode($RSAPublicKey), 64) .
                                     '-----END PUBLIC KEY-----';
                }

return $RSAPublicKey;
        }
    }

/**
     * Break a public or private key down into its constituant components
     *
     * @access private
     * @see self::_convertPublicKey()
     * @see self::_convertPrivateKey()
     * @param string|array $key
     * @param int $type
     * @return array|bool
     */
    function _parseKey($key, $type)
    {
        if ($type != self::PUBLIC_FORMAT_RAW && !is_string($key)) {
            return false;
        }

switch ($type) {
            case self::PUBLIC_FORMAT_RAW:
                if (!is_array($key)) {
                    return false;
                }
                $components = array();
                switch (true) {
                    case isset($key['e']):
                        $components['publicExponent'] = $key['e']->copy();
                        break;
                    case isset($key['exponent']):
                        $components['publicExponent'] = $key['exponent']->copy();
                        break;
                    case isset($key['publicExponent']):
                        $components['publicExponent'] = $key['publicExponent']->copy();
                        break;
                    case isset($key[0]):
                        $components['publicExponent'] = $key[0]->copy();
                }
                switch (true) {
                    case isset($key['n']):
                        $components['modulus'] = $key['n']->copy();
                        break;
                    case isset($key['modulo']):
                        $components['modulus'] = $key['modulo']->copy();
                        break;
                    case isset($key['modulus']):
                        $components['modulus'] = $key['modulus']->copy();
                        break;
                    case isset($key[1]):
                        $components['modulus'] = $key[1]->copy();
                }
                return isset($components['modulus']) && isset($components['publicExponent']) ? $components : false;
            case self::PRIVATE_FORMAT_PKCS1:
            case self::PRIVATE_FORMAT_PKCS8:
            case self::PUBLIC_FORMAT_PKCS1:
                /* Although PKCS#1 proposes a format that public and private keys can use, encrypting them is
                   "outside the scope" of PKCS#1.  PKCS#1 then refers you to PKCS#12 and PKCS#15 if you're wanting to
                   protect private keys, however, that's not what OpenSSL* does.  OpenSSL protects private keys by adding
                   two new "fields" to the key - DEK-Info and Proc-Type.  These fields are discussed here:

http://tools.ietf.org/html/rfc1421#section-4.6.1.1
                   http://tools.ietf.org/html/rfc1421#section-4.6.1.3

DES-EDE3-CBC as an algorithm, however, is not discussed anywhere, near as I can tell.
                   DES-CBC and DES-EDE are discussed in RFC1423, however, DES-EDE3-CBC isn't, nor is its key derivation
                   function.  As is, the definitive authority on this encoding scheme isn't the IETF but rather OpenSSL's
                   own implementation.  ie. the implementation *is* the standard and any bugs that may exist in that
                   implementation are part of the standard, as well.

* OpenSSL is the de facto standard.  It's utilized by OpenSSH and other projects */
                if (preg_match('#DEK-Info: (.+),(.+)#', $key, $matches)) {
                    $iv = pack('H*', trim($matches[2]));
                    $symkey = pack('H*', md5($this->password . substr($iv, 0, 8))); // symkey is short for symmetric key
                    $symkey.= pack('H*', md5($symkey . $this->password . substr($iv, 0, 8)));
                    // remove the Proc-Type / DEK-Info sections as they're no longer needed
                    $key = preg_replace('#^(?:Proc-Type|DEK-Info): .*#m', '', $key);
                    $ciphertext = $this->_extractBER($key);
                    if ($ciphertext === false) {
                        $ciphertext = $key;
                    }
                    switch ($matches[1]) {
                        case 'AES-256-CBC':
                            $crypto = new AES();
                            break;
                        case 'AES-128-CBC':
                            $symkey = substr($symkey, 0, 16);
                            $crypto = new AES();
                            break;
                        case 'DES-EDE3-CFB':
                            $crypto = new TripleDES(Base::MODE_CFB);
                            break;
                        case 'DES-EDE3-CBC':
                            $symkey = substr($symkey, 0, 24);
                            $crypto = new TripleDES();
                            break;
                        case 'DES-CBC':
                            $crypto = new DES();
                            break;
                        default:
                            return false;
                    }
                    $crypto->setKey($symkey);
                    $crypto->setIV($iv);
                    $decoded = $crypto->decrypt($ciphertext);
                } else {
                    $decoded = $this->_extractBER($key);
                }

if ($decoded !== false) {
                    $key = $decoded;
                }

$components = array();

if (ord($this->_string_shift($key)) != self::ASN1_SEQUENCE) {
                    return false;
                }
                if ($this->_decodeLength($key) != strlen($key)) {
                    return false;
                }

$tag = ord($this->_string_shift($key));
                /* intended for keys for which OpenSSL's asn1parse returns the following:

0:d=0  hl=4 l= 631 cons: SEQUENCE
                    4:d=1  hl=2 l=   1 prim:  INTEGER           :00
                    7:d=1  hl=2 l=  13 cons:  SEQUENCE
                    9:d=2  hl=2 l=   9 prim:   OBJECT            :rsaEncryption
                   20:d=2  hl=2 l=   0 prim:   NULL
                   22:d=1  hl=4 l= 609 prim:  OCTET STRING

ie. PKCS8 keys*/

if ($tag == self::ASN1_INTEGER && substr($key, 0, 3) == "\x01\x00\x30") {
                    $this->_string_shift($key, 3);
                    $tag = self::ASN1_SEQUENCE;
                }

if ($tag == self::ASN1_SEQUENCE) {
                    $temp = $this->_string_shift($key, $this->_decodeLength($key));
                    if (ord($this->_string_shift($temp)) != self::ASN1_OBJECT) {
                        return false;
                    }
                    $length = $this->_decodeLength($temp);
                    switch ($this->_string_shift($temp, $length)) {
                        case "\x2a\x86\x48\x86\xf7\x0d\x01\x01\x01": // rsaEncryption
                        case "\x2A\x86\x48\x86\xF7\x0D\x01\x01\x0A": // rsaPSS
                            break;
                        case "\x2a\x86\x48\x86\xf7\x0d\x01\x05\x03": // pbeWithMD5AndDES-CBC
                            /*
                               PBEParameter ::= SEQUENCE {
                                   salt OCTET STRING (SIZE(8)),
                                   iterationCount INTEGER }
                            */
                            if (ord($this->_string_shift($temp)) != self::ASN1_SEQUENCE) {
                                return false;
                            }
                            if ($this->_decodeLength($temp) != strlen($temp)) {
                                return false;
                            }
                            $this->_string_shift($temp); // assume it's an octet string
                            $salt = $this->_string_shift($temp, $this->_decodeLength($temp));
                            if (ord($this->_string_shift($temp)) != self::ASN1_INTEGER) {
                                return false;
                            }
                            $this->_decodeLength($temp);
                            list(, $iterationCount) = unpack('N', str_pad($temp, 4, chr(0), STR_PAD_LEFT));
                            $this->_string_shift($key); // assume it's an octet string
                            $length = $this->_decodeLength($key);
                            if (strlen($key) != $length) {
                                return false;
                            }

$crypto = new DES();
                            $crypto->setPassword($this->password, 'pbkdf1', 'md5', $salt, $iterationCount);
                            $key = $crypto->decrypt($key);
                            if ($key === false) {
                                return false;
                            }
                            return $this->_parseKey($key, self::PRIVATE_FORMAT_PKCS1);
                        default:
                            return false;
                    }
                    /* intended for keys for which OpenSSL's asn1parse returns the following:

0:d=0  hl=4 l= 290 cons: SEQUENCE
                        4:d=1  hl=2 l=  13 cons:  SEQUENCE
                        6:d=2  hl=2 l=   9 prim:   OBJECT            :rsaEncryption
                       17:d=2  hl=2 l=   0 prim:   NULL
                       19:d=1  hl=4 l= 271 prim:  BIT STRING */
                    $tag = ord($this->_string_shift($key)); // skip over the BIT STRING / OCTET STRING tag
                    $this->_decodeLength($key); // skip over the BIT STRING / OCTET STRING length
                    // "The initial octet shall encode, as an unsigned binary integer wtih bit 1 as the least significant bit, the number of
                    //  unused bits in the final subsequent octet. The number shall be in the range zero to seven."
                    //  -- http://www.itu.int/ITU-T/studygroups/com17/languages/X.690-0207.pdf (section 8.6.2.2)
                    if ($tag == self::ASN1_BITSTRING) {
                        $this->_string_shift($key);
                    }
                    if (ord($this->_string_shift($key)) != self::ASN1_SEQUENCE) {
                        return false;
                    }
                    if ($this->_decodeLength($key) != strlen($key)) {
                        return false;
                    }
                    $tag = ord($this->_string_shift($key));
                }
                if ($tag != self::ASN1_INTEGER) {
                    return false;
                }

$length = $this->_decodeLength($key);
                $temp = $this->_string_shift($key, $length);
                if (strlen($temp) != 1 || ord($temp) > 2) {
                    $components['modulus'] = new BigInteger($temp, 256);
                    $this->_string_shift($key); // skip over self::ASN1_INTEGER
                    $length = $this->_decodeLength($key);
                    $components[$type == self::PUBLIC_FORMAT_PKCS1 ? 'publicExponent' : 'privateExponent'] = new BigInteger($this->_string_shift($key, $length), 256);

return $components;
                }
                if (ord($this->_string_shift($key)) != self::ASN1_INTEGER) {
                    return false;
                }
                $length = $this->_decodeLength($key);
                $components['modulus'] = new BigInteger($this->_string_shift($key, $length), 256);
                $this->_string_shift($key);
                $length = $this->_decodeLength($key);
                $components['publicExponent'] = new BigInteger($this->_string_shift($key, $length), 256);
                $this->_string_shift($key);
                $length = $this->_decodeLength($key);
                $components['privateExponent'] = new BigInteger($this->_string_shift($key, $length), 256);
                $this->_string_shift($key);
                $length = $this->_decodeLength($key);
                $components['primes'] = array(1 => new BigInteger($this->_string_shift($key, $length), 256));
                $this->_string_shift($key);
                $length = $this->_decodeLength($key);
                $components['primes'][] = new BigInteger($this->_string_shift($key, $length), 256);
                $this->_string_shift($key);
                $length = $this->_decodeLength($key);
                $components['exponents'] = array(1 => new BigInteger($this->_string_shift($key, $length), 256));
                $this->_string_shift($key);
                $length = $this->_decodeLength($key);
                $components['exponents'][] = new BigInteger($this->_string_shift($key, $length), 256);
                $this->_string_shift($key);
                $length = $this->_decodeLength($key);
                $components['coefficients'] = array(2 => new BigInteger($this->_string_shift($key, $length), 256));

if (!empty($key)) {
                    if (ord($this->_string_shift($key)) != self::ASN1_SEQUENCE) {
                        return false;
                    }
                    $this->_decodeLength($key);
                    while (!empty($key)) {
                        if (ord($this->_string_shift($key)) != self::ASN1_SEQUENCE) {
                            return false;
                        }
                        $this->_decodeLength($key);
                        $key = substr($key, 1);
                        $length = $this->_decodeLength($key);
                        $components['primes'][] = new BigInteger($this->_string_shift($key, $length), 256);
                        $this->_string_shift($key);
                        $length = $this->_decodeLength($key);
                        $components['exponents'][] = new BigInteger($this->_string_shift($key, $length), 256);
                        $this->_string_shift($key);
                        $length = $this->_decodeLength($key);
                        $components['coefficients'][] = new BigInteger($this->_string_shift($key, $length), 256);
                    }
                }

return $components;
            case self::PUBLIC_FORMAT_OPENSSH:
                $parts = explode(' ', $key, 3);

$key = isset($parts[1]) ? base64_decode($parts[1]) : false;
                if ($key === false) {
                    return false;
                }

$comment = isset($parts[2]) ? $parts[2] : false;

$cleanup = substr($key, 0, 11) == "\0\0\0\7ssh-rsa";

if (strlen($key) <= 4) {
                    return false;
                }
                extract(unpack('Nlength', $this->_string_shift($key, 4)));
                $publicExponent = new BigInteger($this->_string_shift($key, $length), -256);
                if (strlen($key) <= 4) {
                    return false;
                }
                extract(unpack('Nlength', $this->_string_shift($key, 4)));
                $modulus = new BigInteger($this->_string_shift($key, $length), -256);

if ($cleanup && strlen($key)) {
                    if (strlen($key) <= 4) {
                        return false;
                    }
                    extract(unpack('Nlength', $this->_string_shift($key, 4)));
                    $realModulus = new BigInteger($this->_string_shift($key, $length), -256);
                    return strlen($key) ? false : array(
                        'modulus' => $realModulus,
                        'publicExponent' => $modulus,
                        'comment' => $comment
                    );
                } else {
                    return strlen($key) ? false : array(
                        'modulus' => $modulus,
                        'publicExponent' => $publicExponent,
                        'comment' => $comment
                    );
                }
            // http://www.w3.org/TR/xmldsig-core/#sec-RSAKeyValue
            // http://en.wikipedia.org/wiki/XML_Signature
            case self::PRIVATE_FORMAT_XML:
            case self::PUBLIC_FORMAT_XML:
                $this->components = array();

$xml = xml_parser_create('UTF-8');
                xml_set_object($xml, $this);
                xml_set_element_handler($xml, '_start_element_handler', '_stop_element_handler');
                xml_set_character_data_handler($xml, '_data_handler');
                // add <xml></xml> to account for "dangling" tags like <BitStrength>...</BitStrength> that are sometimes added
                if (!xml_parse($xml, '<xml>' . $key . '</xml>')) {
                    xml_parser_free($xml);
                    unset($xml);
                    return false;
                }

xml_parser_free($xml);
                unset($xml);

return isset($this->components['modulus']) && isset($this->components['publicExponent']) ? $this->components : false;
            // from PuTTY's SSHPUBK.C
            case self::PRIVATE_FORMAT_PUTTY:
                $components = array();
                $key = preg_split('#\r\n|\r|\n#', $key);
                $type = trim(preg_replace('#PuTTY-User-Key-File-2: (.+)#', '$1', $key[0]));
                if ($type != 'ssh-rsa') {
                    return false;
                }
                $encryption = trim(preg_replace('#Encryption: (.+)#', '$1', $key[1]));
                $comment = trim(preg_replace('#Comment: (.+)#', '$1', $key[2]));

$publicLength = trim(preg_replace('#Public-Lines: (\d+)#', '$1', $key[3]));
                $public = base64_decode(implode('', array_map('trim', array_slice($key, 4, $publicLength))));
                $public = substr($public, 11);
                extract(unpack('Nlength', $this->_string_shift($public, 4)));
                $components['publicExponent'] = new BigInteger($this->_string_shift($public, $length), -256);
                extract(unpack('Nlength', $this->_string_shift($public, 4)));
                $components['modulus'] = new BigInteger($this->_string_shift($public, $length), -256);

$privateLength = trim(preg_replace('#Private-Lines: (\d+)#', '$1', $key[$publicLength + 4]));
                $private = base64_decode(implode('', array_map('trim', array_slice($key, $publicLength + 5, $privateLength))));

switch ($encryption) {
                    case 'aes256-cbc':
                        $symkey = '';
                        $sequence = 0;
                        while (strlen($symkey) < 32) {
                            $temp = pack('Na*', $sequence++, $this->password);
                            $symkey.= pack('H*', sha1($temp));
                        }
                        $symkey = substr($symkey, 0, 32);
                        $crypto = new AES();
                }

if ($encryption != 'none') {
                    $crypto->setKey($symkey);
                    $crypto->disablePadding();
                    $private = $crypto->decrypt($private);
                    if ($private === false) {
                        return false;
                    }
                }

extract(unpack('Nlength', $this->_string_shift($private, 4)));
                if (strlen($private) < $length) {
                    return false;
                }
                $components['privateExponent'] = new BigInteger($this->_string_shift($private, $length), -256);
                extract(unpack('Nlength', $this->_string_shift($private, 4)));
                if (strlen($private) < $length) {
                    return false;
                }
                $components['primes'] = array(1 => new BigInteger($this->_string_shift($private, $length), -256));
                extract(unpack('Nlength', $this->_string_shift($private, 4)));
                if (strlen($private) < $length) {
                    return false;
                }
                $components['primes'][] = new BigInteger($this->_string_shift($private, $length), -256);

$temp = $components['primes'][1]->subtract($this->one);
                $components['exponents'] = array(1 => $components['publicExponent']->modInverse($temp));
                $temp = $components['primes'][2]->subtract($this->one);
                $components['exponents'][] = $components['publicExponent']->modInverse($temp);

extract(unpack('Nlength', $this->_string_shift($private, 4)));
                if (strlen($private) < $length) {
                    return false;
                }
                $components['coefficients'] = array(2 => new BigInteger($this->_string_shift($private, $length), -256));

return $components;
            case self::PRIVATE_FORMAT_OPENSSH:
                $components = array();
                $decoded = $this->_extractBER($key);
                $magic = $this->_string_shift($decoded, 15);
                if ($magic !== "openssh-key-v1\0") {
                    return false;
                }
                $options = $this->_string_shift($decoded, 24);
                // \0\0\0\4none = ciphername
                // \0\0\0\4none = kdfname
                // \0\0\0\0 = kdfoptions
                // \0\0\0\1 = numkeys
                if ($options != "\0\0\0\4none\0\0\0\4none\0\0\0\0\0\0\0\1") {
                    return false;
                }
                extract(unpack('Nlength', $this->_string_shift($decoded, 4)));
                if (strlen($decoded) < $length) {
                    return false;
                }
                $publicKey = $this->_string_shift($decoded, $length);
                extract(unpack('Nlength', $this->_string_shift($decoded, 4)));
                if (strlen($decoded) < $length) {
                    return false;
                }
                $paddedKey = $this->_string_shift($decoded, $length);

if ($this->_string_shift($publicKey, 11) !== "\0\0\0\7ssh-rsa") {
                    return false;
                }

$checkint1 = $this->_string_shift($paddedKey, 4);
                $checkint2 = $this->_string_shift($paddedKey, 4);
                if (strlen($checkint1) != 4 || $checkint1 !== $checkint2) {
                    return false;
                }

if ($this->_string_shift($paddedKey, 11) !== "\0\0\0\7ssh-rsa") {
                    return false;
                }

$values = array(
                    &$components['modulus'],
                    &$components['publicExponent'],
                    &$components['privateExponent'],
                    &$components['coefficients'][2],
                    &$components['primes'][1],
                    &$components['primes'][2]
                );

foreach ($values as &$value) {
                    extract(unpack('Nlength', $this->_string_shift($paddedKey, 4)));
                    if (strlen($paddedKey) < $length) {
                        return false;
                    }
                    $value = new BigInteger($this->_string_shift($paddedKey, $length), -256);
                }

extract(unpack('Nlength', $this->_string_shift($paddedKey, 4)));
                if (strlen($paddedKey) < $length) {
                    return false;
                }
                $components['comment'] = $this->_string_shift($decoded, $length);

return $components;
        }

return false;
    }

/**
     * Returns the key size
     *
     * More specifically, this returns the size of the modulo in bits.
     *
     * @access public
     * @return int
     */
    function getSize()
    {
        return !isset($this->modulus) ? 0 : strlen($this->modulus->toBits());
    }

/**
     * Start Element Handler
     *
     * Called by xml_set_element_handler()
     *
     * @access private
     * @param resource $parser
     * @param string $name
     * @param array $attribs
     */
    function _start_element_handler($parser, $name, $attribs)
    {
        //$name = strtoupper($name);
        switch ($name) {
            case 'MODULUS':
                $this->current = &$this->components['modulus'];
                break;
            case 'EXPONENT':
                $this->current = &$this->components['publicExponent'];
                break;
            case 'P':
                $this->current = &$this->components['primes'][1];
                break;
            case 'Q':
                $this->current = &$this->components['primes'][2];
                break;
            case 'DP':
                $this->current = &$this->components['exponents'][1];
                break;
            case 'DQ':
                $this->current = &$this->components['exponents'][2];
                break;
            case 'INVERSEQ':
                $this->current = &$this->components['coefficients'][2];
                break;
            case 'D':
                $this->current = &$this->components['privateExponent'];
        }
        $this->current = '';
    }

/**
     * Stop Element Handler
     *
     * Called by xml_set_element_handler()
     *
     * @access private
     * @param resource $parser
     * @param string $name
     */
    function _stop_element_handler($parser, $name)
    {
        if (isset($this->current)) {
            $this->current = new BigInteger(base64_decode($this->current), 256);
            unset($this->current);
        }
    }

/**
     * Data Handler
     *
     * Called by xml_set_character_data_handler()
     *
     * @access private
     * @param resource $parser
     * @param string $data
     */
    function _data_handler($parser, $data)
    {
        if (!isset($this->current) || is_object($this->current)) {
            return;
        }
        $this->current.= trim($data);
    }

/**
     * Loads a public or private key
     *
     * Returns true on success and false on failure (ie. an incorrect password was provided or the key was malformed)
     *
     * @access public
     * @param string|RSA|array $key
     * @param bool|int $type optional
     * @return bool
     */
    function loadKey($key, $type = false)
    {
        if ($key instanceof RSA) {
            $this->privateKeyFormat = $key->privateKeyFormat;
            $this->publicKeyFormat = $key->publicKeyFormat;
            $this->k = $key->k;
            $this->hLen = $key->hLen;
            $this->sLen = $key->sLen;
            $this->mgfHLen = $key->mgfHLen;
            $this->encryptionMode = $key->encryptionMode;
            $this->signatureMode = $key->signatureMode;
            $this->password = $key->password;
            $this->configFile = $key->configFile;
            $this->comment = $key->comment;

if (is_object($key->hash)) {
                $this->hash = new Hash($key->hash->getHash());
            }
            if (is_object($key->mgfHash)) {
                $this->mgfHash = new Hash($key->mgfHash->getHash());
            }

if (is_object($key->modulus)) {
                $this->modulus = $key->modulus->copy();
            }
            if (is_object($key->exponent)) {
                $this->exponent = $key->exponent->copy();
            }
            if (is_object($key->publicExponent)) {
                $this->publicExponent = $key->publicExponent->copy();
            }

$this->primes = array();
            $this->exponents = array();
            $this->coefficients = array();

foreach ($this->primes as $prime) {
                $this->primes[] = $prime->copy();
            }
            foreach ($this->exponents as $exponent) {
                $this->exponents[] = $exponent->copy();
            }
            foreach ($this->coefficients as $coefficient) {
                $this->coefficients[] = $coefficient->copy();
            }

return true;
        }

if ($type === false) {
            $types = array(
                self::PUBLIC_FORMAT_RAW,
                self::PRIVATE_FORMAT_PKCS1,
                self::PRIVATE_FORMAT_XML,
                self::PRIVATE_FORMAT_PUTTY,
                self::PUBLIC_FORMAT_OPENSSH,
                self::PRIVATE_FORMAT_OPENSSH
            );
            foreach ($types as $type) {
                $components = $this->_parseKey($key, $type);
                if ($components !== false) {
                    break;
                }
            }
        } else {
            $components = $this->_parseKey($key, $type);
        }

if ($components === false) {
            $this->comment = null;
            $this->modulus = null;
            $this->k = null;
            $this->exponent = null;
            $this->primes = null;
            $this->exponents = null;
            $this->coefficients = null;
            $this->publicExponent = null;

return false;
        }

if (isset($components['comment']) && $components['comment'] !== false) {
            $this->comment = $components['comment'];
        }
        $this->modulus = $components['modulus'];
        $this->k = strlen($this->modulus->toBytes());
        $this->exponent = isset($components['privateExponent']) ? $components['privateExponent'] : $components['publicExponent'];
        if (isset($components['primes'])) {
            $this->primes = $components['primes'];
            $this->exponents = $components['exponents'];
            $this->coefficients = $components['coefficients'];
            $this->publicExponent = $components['publicExponent'];
        } else {
            $this->primes = array();
            $this->exponents = array();
            $this->coefficients = array();
            $this->publicExponent = false;
        }

switch ($type) {
            case self::PUBLIC_FORMAT_OPENSSH:
            case self::PUBLIC_FORMAT_RAW:
                $this->setPublicKey();
                break;
            case self::PRIVATE_FORMAT_PKCS1:
                switch (true) {
                    case strpos($key, '-BEGIN PUBLIC KEY-') !== false:
                    case strpos($key, '-BEGIN RSA PUBLIC KEY-') !== false:
                        $this->setPublicKey();
                }
        }

return true;
    }

/**
     * Sets the password
     *
     * Private keys can be encrypted with a password.  To unset the password, pass in the empty string or false.
     * Or rather, pass in $password such that empty($password) && !is_string($password) is true.
     *
     * @see self::createKey()
     * @see self::loadKey()
     * @access public
     * @param string $password
     */
    function setPassword($password = false)
    {
        $this->password = $password;
    }

/**
     * Defines the public key
     *
     * Some private key formats define the public exponent and some don't.  Those that don't define it are problematic when
     * used in certain contexts.  For example, in SSH-2, RSA authentication works by sending the public key along with a
     * message signed by the private key to the server.  The SSH-2 server looks the public key up in an index of public keys
     * and if it's present then proceeds to verify the signature.  Problem is, if your private key doesn't include the public
     * exponent this won't work unless you manually add the public exponent. phpseclib tries to guess if the key being used
     * is the public key but in the event that it guesses incorrectly you might still want to explicitly set the key as being
     * public.
     *
     * Do note that when a new key is loaded the index will be cleared.
     *
     * Returns true on success, false on failure
     *
     * @see self::getPublicKey()
     * @access public
     * @param string $key optional
     * @param int $type optional
     * @return bool
     */
    function setPublicKey($key = false, $type = false)
    {
        // if a public key has already been loaded return false
        if (!empty($this->publicExponent)) {
            return false;
        }

if ($key === false && !empty($this->modulus)) {
            $this->publicExponent = $this->exponent;
            return true;
        }

if ($type === false) {
            $types = array(
                self::PUBLIC_FORMAT_RAW,
                self::PUBLIC_FORMAT_PKCS1,
                self::PUBLIC_FORMAT_XML,
                self::PUBLIC_FORMAT_OPENSSH
            );
            foreach ($types as $type) {
                $components = $this->_parseKey($key, $type);
                if ($components !== false) {
                    break;
                }
            }
        } else {
            $components = $this->_parseKey($key, $type);
        }

if ($components === false) {
            return false;
        }

if (empty($this->modulus) || !$this->modulus->equals($components['modulus'])) {
            $this->modulus = $components['modulus'];
            $this->exponent = $this->publicExponent = $components['publicExponent'];
            return true;
        }

$this->publicExponent = $components['publicExponent'];

return true;
    }

/**
     * Defines the private key
     *
     * If phpseclib guessed a private key was a public key and loaded it as such it might be desirable to force
     * phpseclib to treat the key as a private key. This function will do that.
     *
     * Do note that when a new key is loaded the index will be cleared.
     *
     * Returns true on success, false on failure
     *
     * @see self::getPublicKey()
     * @access public
     * @param string $key optional
     * @param int $type optional
     * @return bool
     */
    function setPrivateKey($key = false, $type = false)
    {
        if ($key === false && !empty($this->publicExponent)) {
            $this->publicExponent = false;
            return true;
        }

$rsa = new RSA();
        if (!$rsa->loadKey($key, $type)) {
            return false;
        }
        $rsa->publicExponent = false;

// don't overwrite the old key if the new key is invalid
        $this->loadKey($rsa);
        return true;
    }

/**
     * Returns the public key
     *
     * The public key is only returned under two circumstances - if the private key had the public key embedded within it
     * or if the public key was set via setPublicKey().  If the currently loaded key is supposed to be the public key this
     * function won't return it since this library, for the most part, doesn't distinguish between public and private keys.
     *
     * @see self::getPublicKey()
     * @access public
     * @param int $type optional
     */
    function getPublicKey($type = self::PUBLIC_FORMAT_PKCS8)
    {
        if (empty($this->modulus) || empty($this->publicExponent)) {
            return false;
        }

$oldFormat = $this->publicKeyFormat;
        $this->publicKeyFormat = $type;
        $temp = $this->_convertPublicKey($this->modulus, $this->publicExponent);
        $this->publicKeyFormat = $oldFormat;
        return $temp;
    }

/**
     * Returns the public key's fingerprint
     *
     * The public key's fingerprint is returned, which is equivalent to running `ssh-keygen -lf rsa.pub`. If there is
     * no public key currently loaded, false is returned.
     * Example output (md5): "c1:b1:30:29:d7:b8:de:6c:97:77:10:d7:46:41:63:87" (as specified by RFC 4716)
     *
     * @access public
     * @param string $algorithm The hashing algorithm to be used. Valid options are 'md5' and 'sha256'. False is returned
     * for invalid values.
     * @return mixed
     */
    function getPublicKeyFingerprint($algorithm = 'md5')
    {
        if (empty($this->modulus) || empty($this->publicExponent)) {
            return false;
        }

$modulus = $this->modulus->toBytes(true);
        $publicExponent = $this->publicExponent->toBytes(true);

$RSAPublicKey = pack('Na*Na*Na*', strlen('ssh-rsa'), 'ssh-rsa', strlen($publicExponent), $publicExponent, strlen($modulus), $modulus);

switch ($algorithm) {
            case 'sha256':
                $hash = new Hash('sha256');
                $base = base64_encode($hash->hash($RSAPublicKey));
                return substr($base, 0, strlen($base) - 1);
            case 'md5':
                return substr(chunk_split(md5($RSAPublicKey), 2, ':'), 0, -1);
            default:
                return false;
        }
    }

/**
     * Returns the private key
     *
     * The private key is only returned if the currently loaded key contains the constituent prime numbers.
     *
     * @see self::getPublicKey()
     * @access public
     * @param int $type optional
     * @return mixed
     */
    function getPrivateKey($type = self::PUBLIC_FORMAT_PKCS1)
    {
        if (empty($this->primes)) {
            return false;
        }

$oldFormat = $this->privateKeyFormat;
        $this->privateKeyFormat = $type;
        $temp = $this->_convertPrivateKey($this->modulus, $this->publicExponent, $this->exponent, $this->primes, $this->exponents, $this->coefficients);
        $this->privateKeyFormat = $oldFormat;
        return $temp;
    }

/**
     * Returns a minimalistic private key
     *
     * Returns the private key without the prime number constituants.  Structurally identical to a public key that
     * hasn't been set as the public key
     *
     * @see self::getPrivateKey()
     * @access private
     * @param int $mode optional
     */
    function _getPrivatePublicKey($mode = self::PUBLIC_FORMAT_PKCS8)
    {
        if (empty($this->modulus) || empty($this->exponent)) {
            return false;
        }

$oldFormat = $this->publicKeyFormat;
        $this->publicKeyFormat = $mode;
        $temp = $this->_convertPublicKey($this->modulus, $this->exponent);
        $this->publicKeyFormat = $oldFormat;
        return $temp;
    }

/**
     *  __toString() magic method
     *
     * @access public
     * @return string
     */
    function __toString()
    {
        $key = $this->getPrivateKey($this->privateKeyFormat);
        if ($key !== false) {
            return $key;
        }
        $key = $this->_getPrivatePublicKey($this->publicKeyFormat);
        return $key !== false ? $key : '';
    }

/**
     *  __clone() magic method
     *
     * @access public
     * @return Crypt_RSA
     */
    function __clone()
    {
        $key = new RSA();
        $key->loadKey($this);
        return $key;
    }

/**
     * Generates the smallest and largest numbers requiring $bits bits
     *
     * @access private
     * @param int $bits
     * @return array
     */
    function _generateMinMax($bits)
    {
        $bytes = $bits >> 3;
        $min = str_repeat(chr(0), $bytes);
        $max = str_repeat(chr(0xFF), $bytes);
        $msb = $bits & 7;
        if ($msb) {
            $min = chr(1 << ($msb - 1)) . $min;
            $max = chr((1 << $msb) - 1) . $max;
        } else {
            $min[0] = chr(0x80);
        }

return array(
            'min' => new BigInteger($min, 256),
            'max' => new BigInteger($max, 256)
        );
    }

/**
     * DER-decode the length
     *
     * DER supports lengths up to (2**8)**127, however, we'll only support lengths up to (2**8)**4.  See
     * {@link http://itu.int/ITU-T/studygroups/com17/languages/X.690-0207.pdf#p=13 X.690 paragraph 8.1.3} for more information.
     *
     * @access private
     * @param string $string
     * @return int
     */
    function _decodeLength(&$string)
    {
        $length = ord($this->_string_shift($string));
        if ($length & 0x80) { // definite length, long form
            $length&= 0x7F;
            $temp = $this->_string_shift($string, $length);
            list(, $length) = unpack('N', substr(str_pad($temp, 4, chr(0), STR_PAD_LEFT), -4));
        }
        return $length;
    }

/**
     * DER-encode the length
     *
     * DER supports lengths up to (2**8)**127, however, we'll only support lengths up to (2**8)**4.  See
     * {@link http://itu.int/ITU-T/studygroups/com17/languages/X.690-0207.pdf#p=13 X.690 paragraph 8.1.3} for more information.
     *
     * @access private
     * @param int $length
     * @return string
     */
    function _encodeLength($length)
    {
        if ($length <= 0x7F) {
            return chr($length);
        }

$temp = ltrim(pack('N', $length), chr(0));
        return pack('Ca*', 0x80 | strlen($temp), $temp);
    }

/**
     * String Shift
     *
     * Inspired by array_shift
     *
     * @param string $string
     * @param int $index
     * @return string
     * @access private
     */
    function _string_shift(&$string, $index = 1)
    {
        $substr = substr($string, 0, $index);
        $string = substr($string, $index);
        return $substr;
    }

/**
     * Determines the private key format
     *
     * @see self::createKey()
     * @access public
     * @param int $format
     */
    function setPrivateKeyFormat($format)
    {
        $this->privateKeyFormat = $format;
    }

/**
     * Determines the public key format
     *
     * @see self::createKey()
     * @access public
     * @param int $format
     */
    function setPublicKeyFormat($format)
    {
        $this->publicKeyFormat = $format;
    }

/**
     * Determines which hashing function should be used
     *
     * Used with signature production / verification and (if the encryption mode is self::ENCRYPTION_OAEP) encryption and
     * decryption.  If $hash isn't supported, sha1 is used.
     *
     * @access public
     * @param string $hash
     */
    function setHash($hash)
    {
        // \phpseclib\Crypt\Hash supports algorithms that PKCS#1 doesn't support.  md5-96 and sha1-96, for example.
        switch ($hash) {
            case 'md2':
            case 'md5':
            case 'sha1':
            case 'sha256':
            case 'sha384':
            case 'sha512':
                $this->hash = new Hash($hash);
                $this->hashName = $hash;
                break;
            default:
                $this->hash = new Hash('sha1');
                $this->hashName = 'sha1';
        }
        $this->hLen = $this->hash->getLength();
    }

/**
     * Determines which hashing function should be used for the mask generation function
     *
     * The mask generation function is used by self::ENCRYPTION_OAEP and self::SIGNATURE_PSS and although it's
     * best if Hash and MGFHash are set to the same thing this is not a requirement.
     *
     * @access public
     * @param string $hash
     */
    function setMGFHash($hash)
    {
        // \phpseclib\Crypt\Hash supports algorithms that PKCS#1 doesn't support.  md5-96 and sha1-96, for example.
        switch ($hash) {
            case 'md2':
            case 'md5':
            case 'sha1':
            case 'sha256':
            case 'sha384':
            case 'sha512':
                $this->mgfHash = new Hash($hash);
                break;
            default:
                $this->mgfHash = new Hash('sha1');
        }
        $this->mgfHLen = $this->mgfHash->getLength();
    }

/**
     * Determines the salt length
     *
     * To quote from {@link http://tools.ietf.org/html/rfc3447#page-38 RFC3447#page-38}:
     *
     *    Typical salt lengths in octets are hLen (the length of the output
     *    of the hash function Hash) and 0.
     *
     * @access public
     * @param int $sLen
     */
    function setSaltLength($sLen)
    {
        $this->sLen = $sLen;
    }

/**
     * Integer-to-Octet-String primitive
     *
     * See {@link http://tools.ietf.org/html/rfc3447#section-4.1 RFC3447#section-4.1}.
     *
     * @access private
     * @param \phpseclib\Math\BigInteger $x
     * @param int $xLen
     * @return string
     */
    function _i2osp($x, $xLen)
    {
        $x = $x->toBytes();
        if (strlen($x) > $xLen) {
            user_error('Integer too large');
            return false;
        }
        return str_pad($x, $xLen, chr(0), STR_PAD_LEFT);
    }

/**
     * Octet-String-to-Integer primitive
     *
     * See {@link http://tools.ietf.org/html/rfc3447#section-4.2 RFC3447#section-4.2}.
     *
     * @access private
     * @param int|string|resource $x
     * @return \phpseclib\Math\BigInteger
     */
    function _os2ip($x)
    {
        return new BigInteger($x, 256);
    }

/**
     * Exponentiate with or without Chinese Remainder Theorem
     *
     * See {@link http://tools.ietf.org/html/rfc3447#section-5.1.1 RFC3447#section-5.1.2}.
     *
     * @access private
     * @param \phpseclib\Math\BigInteger $x
     * @return \phpseclib\Math\BigInteger
     */
    function _exponentiate($x)
    {
        switch (true) {
            case empty($this->primes):
            case $this->primes[1]->equals($this->zero):
            case empty($this->coefficients):
            case $this->coefficients[2]->equals($this->zero):
            case empty($this->exponents):
            case $this->exponents[1]->equals($this->zero):
                return $x->modPow($this->exponent, $this->modulus);
        }

$num_primes = count($this->primes);

if (defined('CRYPT_RSA_DISABLE_BLINDING')) {
            $m_i = array(
                1 => $x->modPow($this->exponents[1], $this->primes[1]),
                2 => $x->modPow($this->exponents[2], $this->primes[2])
            );
            $h = $m_i[1]->subtract($m_i[2]);
            $h = $h->multiply($this->coefficients[2]);
            list(, $h) = $h->divide($this->primes[1]);
            $m = $m_i[2]->add($h->multiply($this->primes[2]));

$r = $this->primes[1];
            for ($i = 3; $i <= $num_primes; $i++) {
                $m_i = $x->modPow($this->exponents[$i], $this->primes[$i]);

$r = $r->multiply($this->primes[$i - 1]);

$h = $m_i->subtract($m);
                $h = $h->multiply($this->coefficients[$i]);
                list(, $h) = $h->divide($this->primes[$i]);

$m = $m->add($r->multiply($h));
            }
        } else {
            $smallest = $this->primes[1];
            for ($i = 2; $i <= $num_primes; $i++) {
                if ($smallest->compare($this->primes[$i]) > 0) {
                    $smallest = $this->primes[$i];
                }
            }

$one = new BigInteger(1);

$r = $one->random($one, $smallest->subtract($one));

$m_i = array(
                1 => $this->_blind($x, $r, 1),
                2 => $this->_blind($x, $r, 2)
            );
            $h = $m_i[1]->subtract($m_i[2]);
            $h = $h->multiply($this->coefficients[2]);
            list(, $h) = $h->divide($this->primes[1]);
            $m = $m_i[2]->add($h->multiply($this->primes[2]));

$r = $this->primes[1];
            for ($i = 3; $i <= $num_primes; $i++) {
                $m_i = $this->_blind($x, $r, $i);

$r = $r->multiply($this->primes[$i - 1]);

$h = $m_i->subtract($m);
                $h = $h->multiply($this->coefficients[$i]);
                list(, $h) = $h->divide($this->primes[$i]);

$m = $m->add($r->multiply($h));
            }
        }

return $m;
    }

/**
     * Performs RSA Blinding
     *
     * Protects against timing attacks by employing RSA Blinding.
     * Returns $x->modPow($this->exponents[$i], $this->primes[$i])
     *
     * @access private
     * @param \phpseclib\Math\BigInteger $x
     * @param \phpseclib\Math\BigInteger $r
     * @param int $i
     * @return \phpseclib\Math\BigInteger
     */
    function _blind($x, $r, $i)
    {
        $x = $x->multiply($r->modPow($this->publicExponent, $this->primes[$i]));
        $x = $x->modPow($this->exponents[$i], $this->primes[$i]);

$r = $r->modInverse($this->primes[$i]);
        $x = $x->multiply($r);
        list(, $x) = $x->divide($this->primes[$i]);

return $x;
    }

/**
     * Performs blinded RSA equality testing
     *
     * Protects against a particular type of timing attack described.
     *
     * See {@link http://codahale.com/a-lesson-in-timing-attacks/ A Lesson In Timing Attacks (or, Don't use MessageDigest.isEquals)}
     *
     * Thanks for the heads up singpolyma!
     *
     * @access private
     * @param string $x
     * @param string $y
     * @return bool
     */
    function _equals($x, $y)
    {
        if (function_exists('hash_equals')) {
            return hash_equals($x, $y);
        }

if (strlen($x) != strlen($y)) {
            return false;
        }

$result = "\0";
        $x^= $y;
        for ($i = 0; $i < strlen($x); $i++) {
            $result|= $x[$i];
        }

return $result === "\0";
    }

/**
     * RSAEP
     *
     * See {@link http://tools.ietf.org/html/rfc3447#section-5.1.1 RFC3447#section-5.1.1}.
     *
     * @access private
     * @param \phpseclib\Math\BigInteger $m
     * @return \phpseclib\Math\BigInteger
     */
    function _rsaep($m)
    {
        if ($m->compare($this->zero) < 0 || $m->compare($this->modulus) > 0) {
            user_error('Message representative out of range');
            return false;
        }
        return $this->_exponentiate($m);
    }

/**
     * RSADP
     *
     * See {@link http://tools.ietf.org/html/rfc3447#section-5.1.2 RFC3447#section-5.1.2}.
     *
     * @access private
     * @param \phpseclib\Math\BigInteger $c
     * @return \phpseclib\Math\BigInteger
     */
    function _rsadp($c)
    {
        if ($c->compare($this->zero) < 0 || $c->compare($this->modulus) > 0) {
            user_error('Ciphertext representative out of range');
            return false;
        }
        return $this->_exponentiate($c);
    }

/**
     * RSASP1
     *
     * See {@link http://tools.ietf.org/html/rfc3447#section-5.2.1 RFC3447#section-5.2.1}.
     *
     * @access private
     * @param \phpseclib\Math\BigInteger $m
     * @return \phpseclib\Math\BigInteger
     */
    function _rsasp1($m)
    {
        if ($m->compare($this->zero) < 0 || $m->compare($this->modulus) > 0) {
            user_error('Message representative out of range');
            return false;
        }
        return $this->_exponentiate($m);
    }

/**
     * RSAVP1
     *
     * See {@link http://tools.ietf.org/html/rfc3447#section-5.2.2 RFC3447#section-5.2.2}.
     *
     * @access private
     * @param \phpseclib\Math\BigInteger $s
     * @return \phpseclib\Math\BigInteger
     */
    function _rsavp1($s)
    {
        if ($s->compare($this->zero) < 0 || $s->compare($this->modulus) > 0) {
            user_error('Signature representative out of range');
            return false;
        }
        return $this->_exponentiate($s);
    }

/**
     * MGF1
     *
     * See {@link http://tools.ietf.org/html/rfc3447#appendix-B.2.1 RFC3447#appendix-B.2.1}.
     *
     * @access private
     * @param string $mgfSeed
     * @param int $maskLen
     * @return string
     */
    function _mgf1($mgfSeed, $maskLen)
    {
        // if $maskLen would yield strings larger than 4GB, PKCS#1 suggests a "Mask too long" error be output.

$t = '';
        $count = ceil($maskLen / $this->mgfHLen);
        for ($i = 0; $i < $count; $i++) {
            $c = pack('N', $i);
            $t.= $this->mgfHash->hash($mgfSeed . $c);
        }

return substr($t, 0, $maskLen);
    }

/**
     * RSAES-OAEP-ENCRYPT
     *
     * See {@link http://tools.ietf.org/html/rfc3447#section-7.1.1 RFC3447#section-7.1.1} and
     * {http://en.wikipedia.org/wiki/Optimal_Asymmetric_Encryption_Padding OAES}.
     *
     * @access private
     * @param string $m
     * @param string $l
     * @return string
     */
    function _rsaes_oaep_encrypt($m, $l = '')
    {
        $mLen = strlen($m);

// Length checking

// if $l is larger than two million terrabytes and you're using sha1, PKCS#1 suggests a "Label too long" error
        // be output.

if ($mLen > $this->k - 2 * $this->hLen - 2) {
            user_error('Message too long');
            return false;
        }

// EME-OAEP encoding

$lHash = $this->hash->hash($l);
        $ps = str_repeat(chr(0), $this->k - $mLen - 2 * $this->hLen - 2);
        $db = $lHash . $ps . chr(1) . $m;
        $seed = Random::string($this->hLen);
        $dbMask = $this->_mgf1($seed, $this->k - $this->hLen - 1);
        $maskedDB = $db ^ $dbMask;
        $seedMask = $this->_mgf1($maskedDB, $this->hLen);
        $maskedSeed = $seed ^ $seedMask;
        $em = chr(0) . $maskedSeed . $maskedDB;

// RSA encryption

$m = $this->_os2ip($em);
        $c = $this->_rsaep($m);
        $c = $this->_i2osp($c, $this->k);

// Output the ciphertext C

return $c;
    }

/**
     * RSAES-OAEP-DECRYPT
     *
     * See {@link http://tools.ietf.org/html/rfc3447#section-7.1.2 RFC3447#section-7.1.2}.  The fact that the error
     * messages aren't distinguishable from one another hinders debugging, but, to quote from RFC3447#section-7.1.2:
     *
     *    Note.  Care must be taken to ensure that an opponent cannot
     *    distinguish the different error conditions in Step 3.g, whether by
     *    error message or timing, or, more generally, learn partial
     *    information about the encoded message EM.  Otherwise an opponent may
     *    be able to obtain useful information about the decryption of the
     *    ciphertext C, leading to a chosen-ciphertext attack such as the one
     *    observed by Manger [36].
     *
     * As for $l...  to quote from {@link http://tools.ietf.org/html/rfc3447#page-17 RFC3447#page-17}:
     *
     *    Both the encryption and the decryption operations of RSAES-OAEP take
     *    the value of a label L as input.  In this version of PKCS #1, L is
     *    the empty string; other uses of the label are outside the scope of
     *    this document.
     *
     * @access private
     * @param string $c
     * @param string $l
     * @return string
     */
    function _rsaes_oaep_decrypt($c, $l = '')
    {
        // Length checking

// if $l is larger than two million terrabytes and you're using sha1, PKCS#1 suggests a "Label too long" error
        // be output.

if (strlen($c) != $this->k || $this->k < 2 * $this->hLen + 2) {
            user_error('Decryption error');
            return false;
        }

// RSA decryption

$c = $this->_os2ip($c);
        $m = $this->_rsadp($c);
        if ($m === false) {
            user_error('Decryption error');
            return false;
        }
        $em = $this->_i2osp($m, $this->k);

// EME-OAEP decoding

$lHash = $this->hash->hash($l);
        $y = ord($em[0]);
        $maskedSeed = substr($em, 1, $this->hLen);
        $maskedDB = substr($em, $this->hLen + 1);
        $seedMask = $this->_mgf1($maskedDB, $this->hLen);
        $seed = $maskedSeed ^ $seedMask;
        $dbMask = $this->_mgf1($seed, $this->k - $this->hLen - 1);
        $db = $maskedDB ^ $dbMask;
        $lHash2 = substr($db, 0, $this->hLen);
        $m = substr($db, $this->hLen);
        $hashesMatch = $this->_equals($lHash, $lHash2);
        $leadingZeros = 1;
        $patternMatch = 0;
        $offset = 0;
        for ($i = 0; $i < strlen($m); $i++) {
            $patternMatch|= $leadingZeros & ($m[$i] === "\1");
            $leadingZeros&= $m[$i] === "\0";
            $offset+= $patternMatch ? 0 : 1;
        }

// we do | instead of || to avoid https://en.wikipedia.org/wiki/Short-circuit_evaluation
        // to protect against timing attacks
        if (!$hashesMatch | !$patternMatch) {
            user_error('Decryption error');
            return false;
        }

// Output the message M

return substr($m, $offset + 1);
    }

/**
     * Raw Encryption / Decryption
     *
     * Doesn't use padding and is not recommended.
     *
     * @access private
     * @param string $m
     * @return string
     */
    function _raw_encrypt($m)
    {
        $temp = $this->_os2ip($m);
        $temp = $this->_rsaep($temp);
        return  $this->_i2osp($temp, $this->k);
    }

/**
     * RSAES-PKCS1-V1_5-ENCRYPT
     *
     * See {@link http://tools.ietf.org/html/rfc3447#section-7.2.1 RFC3447#section-7.2.1}.
     *
     * @access private
     * @param string $m
     * @return string
     */
    function _rsaes_pkcs1_v1_5_encrypt($m)
    {
        $mLen = strlen($m);

// Length checking

if ($mLen > $this->k - 11) {
            user_error('Message too long');
            return false;
        }

// EME-PKCS1-v1_5 encoding

$psLen = $this->k - $mLen - 3;
        $ps = '';
        while (strlen($ps) != $psLen) {
            $temp = Random::string($psLen - strlen($ps));
            $temp = str_replace("\x00", '', $temp);
            $ps.= $temp;
        }
        $type = 2;
        // see the comments of _rsaes_pkcs1_v1_5_decrypt() to understand why this is being done
        if (defined('CRYPT_RSA_PKCS15_COMPAT') && (!isset($this->publicExponent) || $this->exponent !== $this->publicExponent)) {
            $type = 1;
            // "The padding string PS shall consist of k-3-||D|| octets. ... for block type 01, they shall have value FF"
            $ps = str_repeat("\xFF", $psLen);
        }
        $em = chr(0) . chr($type) . $ps . chr(0) . $m;

// RSA encryption
        $m = $this->_os2ip($em);
        $c = $this->_rsaep($m);
        $c = $this->_i2osp($c, $this->k);

// Output the ciphertext C

return $c;
    }

/**
     * RSAES-PKCS1-V1_5-DECRYPT
     *
     * See {@link http://tools.ietf.org/html/rfc3447#section-7.2.2 RFC3447#section-7.2.2}.
     *
     * For compatibility purposes, this function departs slightly from the description given in RFC3447.
     * The reason being that RFC2313#section-8.1 (PKCS#1 v1.5) states that ciphertext's encrypted by the
     * private key should have the second byte set to either 0 or 1 and that ciphertext's encrypted by the
     * public key should have the second byte set to 2.  In RFC3447 (PKCS#1 v2.1), the second byte is supposed
     * to be 2 regardless of which key is used.  For compatibility purposes, we'll just check to make sure the
     * second byte is 2 or less.  If it is, we'll accept the decrypted string as valid.
     *
     * As a consequence of this, a private key encrypted ciphertext produced with \phpseclib\Crypt\RSA may not decrypt
     * with a strictly PKCS#1 v1.5 compliant RSA implementation.  Public key encrypted ciphertext's should but
     * not private key encrypted ciphertext's.
     *
     * @access private
     * @param string $c
     * @return string
     */
    function _rsaes_pkcs1_v1_5_decrypt($c)
    {
        // Length checking

if (strlen($c) != $this->k) { // or if k < 11
            user_error('Decryption error');
            return false;
        }

// RSA decryption

$c = $this->_os2ip($c);
        $m = $this->_rsadp($c);

if ($m === false) {
            user_error('Decryption error');
            return false;
        }
        $em = $this->_i2osp($m, $this->k);

// EME-PKCS1-v1_5 decoding

if (ord($em[0]) != 0 || ord($em[1]) > 2) {
            user_error('Decryption error');
            return false;
        }

$ps = substr($em, 2, strpos($em, chr(0), 2) - 2);
        $m = substr($em, strlen($ps) + 3);

if (strlen($ps) < 8) {
            user_error('Decryption error');
            return false;
        }

// Output M

return $m;
    }

/**
     * EMSA-PSS-ENCODE
     *
     * See {@link http://tools.ietf.org/html/rfc3447#section-9.1.1 RFC3447#section-9.1.1}.
     *
     * @access private
     * @param string $m
     * @param int $emBits
     */
    function _emsa_pss_encode($m, $emBits)
    {
        // if $m is larger than two million terrabytes and you're using sha1, PKCS#1 suggests a "Label too long" error
        // be output.

$emLen = ($emBits + 1) >> 3; // ie. ceil($emBits / 8)
        $sLen = $this->sLen !== null ? $this->sLen : $this->hLen;

$mHash = $this->hash->hash($m);
        if ($emLen < $this->hLen + $sLen + 2) {
            user_error('Encoding error');
            return false;
        }

$salt = Random::string($sLen);
        $m2 = "\0\0\0\0\0\0\0\0" . $mHash . $salt;
        $h = $this->hash->hash($m2);
        $ps = str_repeat(chr(0), $emLen - $sLen - $this->hLen - 2);
        $db = $ps . chr(1) . $salt;
        $dbMask = $this->_mgf1($h, $emLen - $this->hLen - 1);
        $maskedDB = $db ^ $dbMask;
        $maskedDB[0] = ~chr(0xFF << ($emBits & 7)) & $maskedDB[0];
        $em = $maskedDB . $h . chr(0xBC);

return $em;
    }

/**
     * EMSA-PSS-VERIFY
     *
     * See {@link http://tools.ietf.org/html/rfc3447#section-9.1.2 RFC3447#section-9.1.2}.
     *
     * @access private
     * @param string $m
     * @param string $em
     * @param int $emBits
     * @return string
     */
    function _emsa_pss_verify($m, $em, $emBits)
    {
        // if $m is larger than two million terrabytes and you're using sha1, PKCS#1 suggests a "Label too long" error
        // be output.

$emLen = ($emBits + 7) >> 3; // ie. ceil($emBits / 8);
        $sLen = $this->sLen !== null ? $this->sLen : $this->hLen;

$mHash = $this->hash->hash($m);
        if ($emLen < $this->hLen + $sLen + 2) {
            return false;
        }

if ($em[strlen($em) - 1] != chr(0xBC)) {
            return false;
        }

$maskedDB = substr($em, 0, -$this->hLen - 1);
        $h = substr($em, -$this->hLen - 1, $this->hLen);
        $temp = chr(0xFF << ($emBits & 7));
        if ((~$maskedDB[0] & $temp) != $temp) {
            return false;
        }
        $dbMask = $this->_mgf1($h, $emLen - $this->hLen - 1);
        $db = $maskedDB ^ $dbMask;
        $db[0] = ~chr(0xFF << ($emBits & 7)) & $db[0];
        $temp = $emLen - $this->hLen - $sLen - 2;
        if (substr($db, 0, $temp) != str_repeat(chr(0), $temp) || ord($db[$temp]) != 1) {
            return false;
        }
        $salt = substr($db, $temp + 1); // should be $sLen long
        $m2 = "\0\0\0\0\0\0\0\0" . $mHash . $salt;
        $h2 = $this->hash->hash($m2);
        return $this->_equals($h, $h2);
    }

/**
     * RSASSA-PSS-SIGN
     *
     * See {@link http://tools.ietf.org/html/rfc3447#section-8.1.1 RFC3447#section-8.1.1}.
     *
     * @access private
     * @param string $m
     * @return string
     */
    function _rsassa_pss_sign($m)
    {
        // EMSA-PSS encoding

$em = $this->_emsa_pss_encode($m, 8 * $this->k - 1);

// RSA signature

$m = $this->_os2ip($em);
        $s = $this->_rsasp1($m);
        $s = $this->_i2osp($s, $this->k);

// Output the signature S

return $s;
    }

/**
     * RSASSA-PSS-VERIFY
     *
     * See {@link http://tools.ietf.org/html/rfc3447#section-8.1.2 RFC3447#section-8.1.2}.
     *
     * @access private
     * @param string $m
     * @param string $s
     * @return string
     */
    function _rsassa_pss_verify($m, $s)
    {
        // Length checking

if (strlen($s) != $this->k) {
            user_error('Invalid signature');
            return false;
        }

// RSA verification

$modBits = strlen($this->modulus->toBits());

$s2 = $this->_os2ip($s);
        $m2 = $this->_rsavp1($s2);
        if ($m2 === false) {
            user_error('Invalid signature');
            return false;
        }
        $em = $this->_i2osp($m2, $this->k);
        if ($em === false) {
            user_error('Invalid signature');
            return false;
        }

// EMSA-PSS verification

return $this->_emsa_pss_verify($m, $em, $modBits - 1);
    }

/**
     * EMSA-PKCS1-V1_5-ENCODE
     *
     * See {@link http://tools.ietf.org/html/rfc3447#section-9.2 RFC3447#section-9.2}.
     *
     * @access private
     * @param string $m
     * @param int $emLen
     * @return string
     */
    function _emsa_pkcs1_v1_5_encode($m, $emLen)
    {
        $h = $this->hash->hash($m);
        if ($h === false) {
            return false;
        }

// see http://tools.ietf.org/html/rfc3447#page-43
        switch ($this->hashName) {
            case 'md2':
                $t = pack('H*', '3020300c06082a864886f70d020205000410');
                break;
            case 'md5':
                $t = pack('H*', '3020300c06082a864886f70d020505000410');
                break;
            case 'sha1':
                $t = pack('H*', '3021300906052b0e03021a05000414');
                break;
            case 'sha256':
                $t = pack('H*', '3031300d060960864801650304020105000420');
                break;
            case 'sha384':
                $t = pack('H*', '3041300d060960864801650304020205000430');
                break;
            case 'sha512':
                $t = pack('H*', '3051300d060960864801650304020305000440');
        }
        $t.= $h;
        $tLen = strlen($t);

if ($emLen < $tLen + 11) {
            user_error('Intended encoded message length too short');
            return false;
        }

$ps = str_repeat(chr(0xFF), $emLen - $tLen - 3);

$em = "\0\1$ps\0$t";

return $em;
    }

/**
     * EMSA-PKCS1-V1_5-ENCODE (without NULL)
     *
     * Quoting https://tools.ietf.org/html/rfc8017#page-65,
     *
     * "The parameters field associated with id-sha1, id-sha224, id-sha256,
     *  id-sha384, id-sha512, id-sha512/224, and id-sha512/256 should
     *  generally be omitted, but if present, it shall have a value of type
     *  NULL"
     *
     * @access private
     * @param string $m
     * @param int $emLen
     * @return string
     */
    function _emsa_pkcs1_v1_5_encode_without_null($m, $emLen)
    {
        $h = $this->hash->hash($m);
        if ($h === false) {
            return false;
        }

switch ($this->hashName) {
            case 'sha1':
                $t = pack('H*', '301f300706052b0e03021a0414');
                break;
            case 'sha256':
                $t = pack('H*', '302f300b06096086480165030402010420');
                break;
            case 'sha384':
                $t = pack('H*', '303f300b06096086480165030402020430');
                break;
            case 'sha512':
                $t = pack('H*', '304f300b06096086480165030402030440');
                break;
            default:
                return false;
        }
        $t.= $h;
        $tLen = strlen($t);

if ($emLen < $tLen + 11) {
            user_error('Intended encoded message length too short');
            return false;
        }

$ps = str_repeat(chr(0xFF), $emLen - $tLen - 3);

$em = "\0\1$ps\0$t";

return $em;
    }

/**
     * RSASSA-PKCS1-V1_5-SIGN
     *
     * See {@link http://tools.ietf.org/html/rfc3447#section-8.2.1 RFC3447#section-8.2.1}.
     *
     * @access private
     * @param string $m
     * @return string
     */
    function _rsassa_pkcs1_v1_5_sign($m)
    {
        // EMSA-PKCS1-v1_5 encoding

$em = $this->_emsa_pkcs1_v1_5_encode($m, $this->k);
        if ($em === false) {
            user_error('RSA modulus too short');
            return false;
        }

// RSA signature

$m = $this->_os2ip($em);
        $s = $this->_rsasp1($m);
        $s = $this->_i2osp($s, $this->k);

// Output the signature S

return $s;
    }

/**
     * RSASSA-PKCS1-V1_5-VERIFY
     *
     * See {@link http://tools.ietf.org/html/rfc3447#section-8.2.2 RFC3447#section-8.2.2}.
     *
     * @access private
     * @param string $m
     * @param string $s
     * @return string
     */
    function _rsassa_pkcs1_v1_5_verify($m, $s)
    {
        // Length checking

if (strlen($s) != $this->k) {
            user_error('Invalid signature');
            return false;
        }

// RSA verification

$s = $this->_os2ip($s);
        $m2 = $this->_rsavp1($s);
        if ($m2 === false) {
            user_error('Invalid signature');
            return false;
        }
        $em = $this->_i2osp($m2, $this->k);
        if ($em === false) {
            user_error('Invalid signature');
            return false;
        }

// EMSA-PKCS1-v1_5 encoding

$em2 = $this->_emsa_pkcs1_v1_5_encode($m, $this->k);
        $em3 = $this->_emsa_pkcs1_v1_5_encode_without_null($m, $this->k);

if ($em2 === false && $em3 === false) {
            user_error('RSA modulus too short');
            return false;
        }

// Compare

return ($em2 !== false && $this->_equals($em, $em2)) ||
               ($em3 !== false && $this->_equals($em, $em3));
    }

/**
     * Set Encryption Mode
     *
     * Valid values include self::ENCRYPTION_OAEP and self::ENCRYPTION_PKCS1.
     *
     * @access public
     * @param int $mode
     */
    function setEncryptionMode($mode)
    {
        $this->encryptionMode = $mode;
    }

/**
     * Set Signature Mode
     *
     * Valid values include self::SIGNATURE_PSS and self::SIGNATURE_PKCS1
     *
     * @access public
     * @param int $mode
     */
    function setSignatureMode($mode)
    {
        $this->signatureMode = $mode;
    }

/**
     * Set public key comment.
     *
     * @access public
     * @param string $comment
     */
    function setComment($comment)
    {
        $this->comment = $comment;
    }

/**
     * Get public key comment.
     *
     * @access public
     * @return string
     */
    function getComment()
    {
        return $this->comment;
    }

/**
     * Encryption
     *
     * Both self::ENCRYPTION_OAEP and self::ENCRYPTION_PKCS1 both place limits on how long $plaintext can be.
     * If $plaintext exceeds those limits it will be broken up so that it does and the resultant ciphertext's will
     * be concatenated together.
     *
     * @see self::decrypt()
     * @access public
     * @param string $plaintext
     * @return string
     */
    function encrypt($plaintext)
    {
        switch ($this->encryptionMode) {
            case self::ENCRYPTION_NONE:
                $plaintext = str_split($plaintext, $this->k);
                $ciphertext = '';
                foreach ($plaintext as $m) {
                    $ciphertext.= $this->_raw_encrypt($m);
                }
                return $ciphertext;
            case self::ENCRYPTION_PKCS1:
                $length = $this->k - 11;
                if ($length <= 0) {
                    return false;
                }

$plaintext = str_split($plaintext, $length);
                $ciphertext = '';
                foreach ($plaintext as $m) {
                    $ciphertext.= $this->_rsaes_pkcs1_v1_5_encrypt($m);
                }
                return $ciphertext;
            //case self::ENCRYPTION_OAEP:
            default:
                $length = $this->k - 2 * $this->hLen - 2;
                if ($length <= 0) {
                    return false;
                }

$plaintext = str_split($plaintext, $length);
                $ciphertext = '';
                foreach ($plaintext as $m) {
                    $ciphertext.= $this->_rsaes_oaep_encrypt($m);
                }
                return $ciphertext;
        }
    }

/**
     * Decryption
     *
     * @see self::encrypt()
     * @access public
     * @param string $ciphertext
     * @return string
     */
    function decrypt($ciphertext)
    {
        if ($this->k <= 0) {
            return false;
        }

$ciphertext = str_split($ciphertext, $this->k);
        $ciphertext[count($ciphertext) - 1] = str_pad($ciphertext[count($ciphertext) - 1], $this->k, chr(0), STR_PAD_LEFT);

$plaintext = '';

switch ($this->encryptionMode) {
            case self::ENCRYPTION_NONE:
                $decrypt = '_raw_encrypt';
                break;
            case self::ENCRYPTION_PKCS1:
                $decrypt = '_rsaes_pkcs1_v1_5_decrypt';
                break;
            //case self::ENCRYPTION_OAEP:
            default:
                $decrypt = '_rsaes_oaep_decrypt';
        }

foreach ($ciphertext as $c) {
            $temp = $this->$decrypt($c);
            if ($temp === false) {
                return false;
            }
            $plaintext.= $temp;
        }

return $plaintext;
    }

/**
     * Create a signature
     *
     * @see self::verify()
     * @access public
     * @param string $message
     * @return string
     */
    function sign($message)
    {
        if (empty($this->modulus) || empty($this->exponent)) {
            return false;
        }

switch ($this->signatureMode) {
            case self::SIGNATURE_PKCS1:
                return $this->_rsassa_pkcs1_v1_5_sign($message);
            //case self::SIGNATURE_PSS:
            default:
                return $this->_rsassa_pss_sign($message);
        }
    }

/**
     * Verifies a signature
     *
     * @see self::sign()
     * @access public
     * @param string $message
     * @param string $signature
     * @return bool
     */
    function verify($message, $signature)
    {
        if (empty($this->modulus) || empty($this->exponent)) {
            return false;
        }

switch ($this->signatureMode) {
            case self::SIGNATURE_PKCS1:
                return $this->_rsassa_pkcs1_v1_5_verify($message, $signature);
            //case self::SIGNATURE_PSS:
            default:
                return $this->_rsassa_pss_verify($message, $signature);
        }
    }

/**
     * Extract raw BER from Base64 encoding
     *
     * @access private
     * @param string $str
     * @return string
     */
    function _extractBER($str)
    {
        /* X.509 certs are assumed to be base64 encoded but sometimes they'll have additional things in them
         * above and beyond the ceritificate.
         * ie. some may have the following preceding the -----BEGIN CERTIFICATE----- line:
         *
         * Bag Attributes
         *     localKeyID: 01 00 00 00
         * subject=/O=organization/OU=org unit/CN=common name
         * issuer=/O=organization/CN=common name
         */
        $temp = preg_replace('#.*?^-+[^-]+-+[\r\n ]*$#ms', '', $str, 1);
        // remove the -----BEGIN CERTIFICATE----- and -----END CERTIFICATE----- stuff
        $temp = preg_replace('#-+[^-]+-+#', '', $temp);
        // remove new lines
        $temp = str_replace(array("\r", "\n", ' '), '', $temp);
        $temp = preg_match('#^[a-zA-Z\d/+]*={0,2}$#', $temp) ? base64_decode($temp) : false;
        return $temp != false ? $temp : $str;
    }
}

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