Add 'mod/openid_server/' from commit 'b6c722ac63d250972fea066b30e58026d00ab3e2'

git-subtree-dir: mod/openid_server
git-subtree-mainline: 2161e2335c9c650b8e44a56f6c9b0bd37546ae1f
git-subtree-split: b6c722ac63d250972fea066b30e58026d00ab3e2

1 files changed, 804 insertions, 0 deletions

diff --git a/mod/openid_server/Crypt/RSA/KeyPair.php b/mod/openid_server/Crypt/RSA/KeyPair.php
new file mode 100644
index 000000000..ecc0b7dc7
--- /dev/null
+++ b/mod/openid_server/Crypt/RSA/KeyPair.php
@@ -0,0 +1,804 @@
+<?php
+/**
+ * Crypt_RSA allows to do following operations:
+ *     - key pair generation
+ *     - encryption and decryption
+ *     - signing and sign validation
+ *
+ * PHP versions 4 and 5
+ *
+ * LICENSE: This source file is subject to version 3.0 of the PHP license
+ * that is available through the world-wide-web at the following URI:
+ * http://www.php.net/license/3_0.txt.  If you did not receive a copy of
+ * the PHP License and are unable to obtain it through the web, please
+ * send a note to license@php.net so we can mail you a copy immediately.
+ *
+ * @category  Encryption
+ * @package   Crypt_RSA
+ * @author    Alexander Valyalkin <valyala@gmail.com>
+ * @copyright 2005 Alexander Valyalkin
+ * @license   http://www.php.net/license/3_0.txt  PHP License 3.0
+ * @version   CVS: $Id: KeyPair.php,v 1.7 2009/01/05 08:30:29 clockwerx Exp $
+ * @link      http://pear.php.net/package/Crypt_RSA
+ */
+
+/**
+ * RSA error handling facilities
+ */
+require_once 'Crypt/RSA/ErrorHandler.php';
+
+/**
+ * loader for RSA math wrappers
+ */
+require_once 'Crypt/RSA/MathLoader.php';
+
+/**
+ * helper class for single key managing
+ */
+require_once 'Crypt/RSA/Key.php';
+
+/**
+ * Crypt_RSA_KeyPair class, derived from Crypt_RSA_ErrorHandler
+ *
+ * Provides the following functions:
+ *  - generate($key) - generates new key pair
+ *  - getPublicKey() - returns public key
+ *  - getPrivateKey() - returns private key
+ *  - getKeyLength() - returns bit key length
+ *  - setRandomGenerator($func_name) - sets random generator to $func_name
+ *  - fromPEMString($str) - retrieves keypair from PEM-encoded string
+ *  - toPEMString() - stores keypair to PEM-encoded string
+ *  - isEqual($keypair2) - compares current keypair to $keypair2
+ *
+ * Example usage:
+ *    // create new 1024-bit key pair
+ *    $key_pair = new Crypt_RSA_KeyPair(1024);
+ *
+ *    // error check
+ *    if ($key_pair->isError()) {
+ *        echo "error while initializing Crypt_RSA_KeyPair object:\n";
+ *        $erorr = $key_pair->getLastError();
+ *        echo $error->getMessage(), "\n";
+ *    }
+ *
+ *    // get public key
+ *    $public_key = $key_pair->getPublicKey();
+ * 
+ *    // get private key
+ *    $private_key = $key_pair->getPrivateKey();
+ * 
+ *    // generate new 512-bit key pair
+ *    $key_pair->generate(512);
+ *
+ *    // error check
+ *    if ($key_pair->isError()) {
+ *        echo "error while generating key pair:\n";
+ *        $erorr = $key_pair->getLastError();
+ *        echo $error->getMessage(), "\n";
+ *    }
+ *
+ *    // get key pair length
+ *    $length = $key_pair->getKeyLength();
+ *
+ *    // set random generator to $func_name, where $func_name
+ *    // consists name of random generator function. See comments
+ *    // before setRandomGenerator() method for details
+ *    $key_pair->setRandomGenerator($func_name);
+ *
+ *    // error check
+ *    if ($key_pair->isError()) {
+ *        echo "error while changing random generator:\n";
+ *        $erorr = $key_pair->getLastError();
+ *        echo $error->getMessage(), "\n";
+ *    }
+ *
+ *    // using factory() method instead of constructor (it returns PEAR_Error object on failure)
+ *    $rsa_obj = &Crypt_RSA_KeyPair::factory($key_len);
+ *    if (PEAR::isError($rsa_obj)) {
+ *        echo "error: ", $rsa_obj->getMessage(), "\n";
+ *    }
+ *
+ *    // read key pair from PEM-encoded string:
+ *    $str = "-----BEGIN RSA PRIVATE KEY-----"
+ *         . "MCsCAQACBHr5LDkCAwEAAQIEBc6jbQIDAOCfAgMAjCcCAk3pAgJMawIDAL41"
+ *         . "-----END RSA PRIVATE KEY-----";
+ *    $keypair = Crypt_RSA_KeyPair::fromPEMString($str);
+ *
+ *    // read key pair from .pem file 'private.pem':
+ *    $str = file_get_contents('private.pem');
+ *    $keypair = Crypt_RSA_KeyPair::fromPEMString($str);
+ *
+ *    // generate and write 1024-bit key pair to .pem file 'private_new.pem'
+ *    $keypair = new Crypt_RSA_KeyPair(1024);
+ *    $str = $keypair->toPEMString();
+ *    file_put_contents('private_new.pem', $str);
+ *
+ *    // compare $keypair1 to $keypair2
+ *    if ($keypair1->isEqual($keypair2)) {
+ *        echo "keypair1 = keypair2\n";
+ *    }
+ *    else {
+ *        echo "keypair1 != keypair2\n";
+ *    }
+ *
+ * @category  Encryption
+ * @package   Crypt_RSA
+ * @author    Alexander Valyalkin <valyala@gmail.com>
+ * @copyright 2005 Alexander Valyalkin
+ * @license   http://www.php.net/license/3_0.txt  PHP License 3.0
+ * @version   Release: @package_version@
+ * @link      http://pear.php.net/package/Crypt_RSA
+ * @access    public
+ */
+class Crypt_RSA_KeyPair extends Crypt_RSA_ErrorHandler
+{
+    /**
+     * Reference to math wrapper object, which is used to
+     * manipulate large integers in RSA algorithm.
+     *
+     * @var object of Crypt_RSA_Math_* class
+     * @access private
+     */
+    var $_math_obj;
+
+    /**
+     * length of each key in the key pair
+     *
+     * @var int
+     * @access private
+     */
+    var $_key_len;
+
+    /**
+     * public key
+     *
+     * @var object of Crypt_RSA_KEY class
+     * @access private
+     */
+    var $_public_key;
+
+    /**
+     * private key
+     *
+     * @var object of Crypt_RSA_KEY class
+     * @access private
+     */
+    var $_private_key;
+
+    /**
+     * name of function, which is used as random generator
+     *
+     * @var string
+     * @access private
+     */
+    var $_random_generator;
+
+    /**
+     * RSA keypair attributes [version, n, e, d, p, q, dmp1, dmq1, iqmp] as associative array
+     *
+     * @var array
+     * @access private
+     */
+    var $_attrs;
+
+    /**
+     * Returns names of keypair attributes from $this->_attrs array
+     *
+     * @return array  Array of keypair attributes names
+     * @access private
+     */
+    function _get_attr_names() 
+    {
+        return array('version', 'n', 'e', 'd', 'p', 'q', 'dmp1', 'dmq1', 'iqmp');
+    }
+
+    /**
+     * Parses ASN.1 string [$str] starting form position [$pos].
+     * Returns tag and string value of parsed object.
+     *
+     * @param string                 $str
+     * @param int                    &$pos
+     * @param Crypt_RSA_ErrorHandler &$err_handler
+     *
+     * @return mixed    Array('tag' => ..., 'str' => ...) on success, false on error
+     * @access private
+     */
+    function _ASN1Parse($str, &$pos, &$err_handler)
+    {
+        $max_pos = strlen($str);
+        if ($max_pos < 2) {
+            $err_handler->pushError("ASN.1 string too short");
+            return false;
+        }
+
+        // get ASN.1 tag value
+        $tag = ord($str[$pos++]) & 0x1f;
+        if ($tag == 0x1f) {
+            $tag = 0;
+            do {
+                $n = ord($str[$pos++]);
+                $tag <<= 7;
+                $tag |= $n & 0x7f;
+            } while (($n & 0x80) && $pos < $max_pos);
+        }
+        if ($pos >= $max_pos) {
+            $err_handler->pushError("ASN.1 string too short");
+            return false;
+        }
+
+        // get ASN.1 object length
+        $len = ord($str[$pos++]);
+        if ($len & 0x80) {
+            $n = $len & 0x1f;
+            $len = 0;
+            while ($n-- && $pos < $max_pos) {
+                $len <<= 8;
+                $len |= ord($str[$pos++]);
+            }
+        }
+        if ($pos >= $max_pos || $len > $max_pos - $pos) {
+            $err_handler->pushError("ASN.1 string too short");
+            return false;
+        }
+
+        // get string value of ASN.1 object
+        $str = substr($str, $pos, $len);
+
+        return array(
+            'tag' => $tag,
+            'str' => $str,
+        );
+    }
+
+    /**
+     * Parses ASN.1 sting [$str] starting from position [$pos].
+     * Returns string representation of number, which can be passed
+     * in bin2int() function of math wrapper.
+     *
+     * @param string                 $str
+     * @param int                    &$pos
+     * @param Crypt_RSA_ErrorHandler &$err_handler
+     *
+     * @return mixed   string representation of parsed number on success, false on error
+     * @access private
+     */
+    function _ASN1ParseInt($str, &$pos, &$err_handler)
+    {
+        $tmp = Crypt_RSA_KeyPair::_ASN1Parse($str, $pos, $err_handler);
+        if ($err_handler->isError()) {
+            return false;
+        }
+        if ($tmp['tag'] != 0x02) {
+            $errstr = sprintf("wrong ASN tag value: 0x%02x. Expected 0x02 (INTEGER)", $tmp['tag']);
+            $err_handler->pushError($errstr);
+            return false;
+        }
+        $pos += strlen($tmp['str']);
+
+        return strrev($tmp['str']);
+    }
+
+    /**
+     * Constructs ASN.1 string from tag $tag and object $str
+     *
+     * @param string $str            ASN.1 object string
+     * @param int    $tag            ASN.1 tag value
+     * @param bool   $is_constructed 
+     * @param bool   $is_private 
+     *
+     * @return ASN.1-encoded string
+     * @access private
+     */
+    function _ASN1Store($str, $tag, $is_constructed = false, $is_private = false)
+    {
+        $out = '';
+
+        // encode ASN.1 tag value
+        $tag_ext = ($is_constructed ? 0x20 : 0) | ($is_private ? 0xc0 : 0);
+        if ($tag < 0x1f) {
+            $out .= chr($tag | $tag_ext);
+        } else {
+            $out .= chr($tag_ext | 0x1f);
+            $tmp = chr($tag & 0x7f);
+            $tag >>= 7;
+            while ($tag) {
+                $tmp .= chr(($tag & 0x7f) | 0x80);
+                $tag >>= 7;
+            }
+            $out .= strrev($tmp);
+        }
+
+        // encode ASN.1 object length
+        $len = strlen($str);
+        if ($len < 0x7f) {
+            $out .= chr($len);
+        } else {
+            $tmp = '';
+            $n = 0;
+            while ($len) {
+                $tmp .= chr($len & 0xff);
+                $len >>= 8;
+                $n++;
+            }
+            $out .= chr($n | 0x80);
+            $out .= strrev($tmp);
+        }
+
+        return $out . $str;
+    }
+
+    /**
+     * Constructs ASN.1 string from binary representation of big integer
+     *
+     * @param string $str binary representation of big integer
+     *
+     * @return ASN.1-encoded string
+     * @access private
+     */
+    function _ASN1StoreInt($str)
+    {
+        $str = strrev($str);
+        return Crypt_RSA_KeyPair::_ASN1Store($str, 0x02);
+    }
+
+    /**
+     * Crypt_RSA_KeyPair constructor.
+     *
+     * Wrapper: name of math wrapper, which will be used to
+     *        perform different operations with big integers.
+     *        See contents of Crypt/RSA/Math folder for examples of wrappers.
+     *        Read docs/Crypt_RSA/docs/math_wrappers.txt for details.
+     *
+     * @param int      $key_len          bit length of key pair, which will be generated in constructor
+     * @param string   $wrapper_name     wrapper name
+     * @param string   $error_handler    name of error handler function
+     * @param callback $random_generator function which will be used as random generator
+     *
+     * @access public
+     */
+    function Crypt_RSA_KeyPair($key_len, $wrapper_name = 'default', $error_handler = '', $random_generator = null)
+    {
+        // set error handler
+        $this->setErrorHandler($error_handler);
+        // try to load math wrapper
+        $obj = &Crypt_RSA_MathLoader::loadWrapper($wrapper_name);
+        if ($this->isError($obj)) {
+            // error during loading of math wrapper
+            $this->pushError($obj);
+            return;
+        }
+        $this->_math_obj = &$obj;
+
+        // set random generator
+        if (!$this->setRandomGenerator($random_generator)) {
+            // error in setRandomGenerator() function
+            return;
+        }
+
+        if (is_array($key_len)) {
+            // ugly BC hack - it is possible to pass RSA private key attributes [version, n, e, d, p, q, dmp1, dmq1, iqmp]
+            // as associative array instead of key length to Crypt_RSA_KeyPair constructor
+            $rsa_attrs = $key_len;
+
+            // convert attributes to big integers
+            $attr_names = $this->_get_attr_names();
+            foreach ($attr_names as $attr) {
+                if (!isset($rsa_attrs[$attr])) {
+                    $this->pushError("missing required RSA attribute [$attr]");
+                    return;
+                }
+                ${$attr} = $this->_math_obj->bin2int($rsa_attrs[$attr]);
+            }
+
+            // check primality of p and q
+            if (!$this->_math_obj->isPrime($p)) {
+                $this->pushError("[p] must be prime");
+                return;
+            }
+            if (!$this->_math_obj->isPrime($q)) {
+                $this->pushError("[q] must be prime");
+                return;
+            }
+
+            // check n = p * q
+            $n1 = $this->_math_obj->mul($p, $q);
+            if ($this->_math_obj->cmpAbs($n, $n1)) {
+                $this->pushError("n != p * q");
+                return;
+            }
+
+            // check e * d = 1 mod (p-1) * (q-1)
+            $p1 = $this->_math_obj->dec($p);
+            $q1 = $this->_math_obj->dec($q);
+            $p1q1 = $this->_math_obj->mul($p1, $q1);
+            $ed = $this->_math_obj->mul($e, $d);
+            $one = $this->_math_obj->mod($ed, $p1q1);
+            if (!$this->_math_obj->isOne($one)) {
+                $this->pushError("e * d != 1 mod (p-1)*(q-1)");
+                return;
+            }
+
+            // check dmp1 = d mod (p-1)
+            $dmp = $this->_math_obj->mod($d, $p1);
+            if ($this->_math_obj->cmpAbs($dmp, $dmp1)) {
+                $this->pushError("dmp1 != d mod (p-1)");
+                return;
+            }
+
+            // check dmq1 = d mod (q-1)
+            $dmq = $this->_math_obj->mod($d, $q1);
+            if ($this->_math_obj->cmpAbs($dmq, $dmq1)) {
+                $this->pushError("dmq1 != d mod (q-1)");
+                return;
+            }
+
+            // check iqmp = 1/q mod p
+            $q1 = $this->_math_obj->invmod($iqmp, $p);
+            if ($this->_math_obj->cmpAbs($q, $q1)) {
+                $this->pushError("iqmp != 1/q mod p");
+                return;
+            }
+
+            // try to create public key object
+            $public_key = &new Crypt_RSA_Key($rsa_attrs['n'], $rsa_attrs['e'], 'public', $wrapper_name, $error_handler);
+            if ($public_key->isError()) {
+                // error during creating public object
+                $this->pushError($public_key->getLastError());
+                return;
+            }
+
+            // try to create private key object
+            $private_key = &new Crypt_RSA_Key($rsa_attrs['n'], $rsa_attrs['d'], 'private', $wrapper_name, $error_handler);
+            if ($private_key->isError()) {
+                // error during creating private key object
+                $this->pushError($private_key->getLastError());
+                return;
+            }
+
+            $this->_public_key = $public_key;
+            $this->_private_key = $private_key;
+            $this->_key_len = $public_key->getKeyLength();
+            $this->_attrs = $rsa_attrs;
+        } else {
+            // generate key pair
+            if (!$this->generate($key_len)) {
+                // error during generating key pair
+                return;
+            }
+        }
+    }
+
+    /**
+     * Crypt_RSA_KeyPair factory.
+     *
+     * Wrapper - Name of math wrapper, which will be used to
+     *        perform different operations with big integers.
+     *        See contents of Crypt/RSA/Math folder for examples of wrappers.
+     *        Read docs/Crypt_RSA/docs/math_wrappers.txt for details.
+     *
+     * @param int      $key_len          bit length of key pair, which will be generated in constructor
+     * @param string   $wrapper_name     wrapper name
+     * @param string   $error_handler    name of error handler function
+     * @param callback $random_generator function which will be used as random generator
+     *
+     * @return object   new Crypt_RSA_KeyPair object on success or PEAR_Error object on failure
+     * @access public
+     */
+    function &factory($key_len, $wrapper_name = 'default', $error_handler = '', $random_generator = null)
+    {
+        $obj = &new Crypt_RSA_KeyPair($key_len, $wrapper_name, $error_handler, $random_generator);
+        if ($obj->isError()) {
+            // error during creating a new object. Return PEAR_Error object
+            return $obj->getLastError();
+        }
+        // object created successfully. Return it
+        return $obj;
+    }
+
+    /**
+     * Generates new Crypt_RSA key pair with length $key_len.
+     * If $key_len is missed, use an old key length from $this->_key_len
+     *
+     * @param int $key_len bit length of key pair, which will be generated
+     *
+     * @return bool         true on success or false on error
+     * @access public
+     */
+    function generate($key_len = null)
+    {
+        if (is_null($key_len)) {
+            // use an old key length
+            $key_len = $this->_key_len;
+            if (is_null($key_len)) {
+                $this->pushError('missing key_len parameter', CRYPT_RSA_ERROR_MISSING_KEY_LEN);
+                return false;
+            }
+        }
+
+        // minimal key length is 8 bit ;)
+        if ($key_len < 8) {
+            $key_len = 8;
+        }
+        // store key length in the _key_len property
+        $this->_key_len = $key_len;
+
+        // set [e] to 0x10001 (65537)
+        $e = $this->_math_obj->bin2int("\x01\x00\x01");
+
+        // generate [p], [q] and [n]
+        $p_len = intval(($key_len + 1) / 2);
+        $q_len = $key_len - $p_len;
+        $p1 = $q1 = 0;
+        do {
+            // generate prime number [$p] with length [$p_len] with the following condition:
+            // GCD($e, $p - 1) = 1
+            do {
+                $p = $this->_math_obj->getPrime($p_len, $this->_random_generator);
+                $p1 = $this->_math_obj->dec($p);
+                $tmp = $this->_math_obj->GCD($e, $p1);
+            } while (!$this->_math_obj->isOne($tmp));
+            // generate prime number [$q] with length [$q_len] with the following conditions:
+            // GCD($e, $q - 1) = 1
+            // $q != $p
+            do {
+                $q = $this->_math_obj->getPrime($q_len, $this->_random_generator);
+                $q1 = $this->_math_obj->dec($q);
+                $tmp = $this->_math_obj->GCD($e, $q1);
+            } while (!$this->_math_obj->isOne($tmp) && !$this->_math_obj->cmpAbs($q, $p));
+            // if (p < q), then exchange them
+            if ($this->_math_obj->cmpAbs($p, $q) < 0) {
+                $tmp = $p;
+                $p = $q;
+                $q = $tmp;
+                $tmp = $p1;
+                $p1 = $q1;
+                $q1 = $tmp;
+            }
+            // calculate n = p * q
+            $n = $this->_math_obj->mul($p, $q);
+        } while ($this->_math_obj->bitLen($n) != $key_len);
+
+        // calculate d = 1/e mod (p - 1) * (q - 1)
+        $pq = $this->_math_obj->mul($p1, $q1);
+        $d = $this->_math_obj->invmod($e, $pq);
+
+        // calculate dmp1 = d mod (p - 1)
+        $dmp1 = $this->_math_obj->mod($d, $p1);
+
+        // calculate dmq1 = d mod (q - 1)
+        $dmq1 = $this->_math_obj->mod($d, $q1);
+
+        // calculate iqmp = 1/q mod p
+        $iqmp = $this->_math_obj->invmod($q, $p);
+
+        // store RSA keypair attributes
+        $this->_attrs = array(
+            'version' => "\x00",
+            'n' => $this->_math_obj->int2bin($n),
+            'e' => $this->_math_obj->int2bin($e),
+            'd' => $this->_math_obj->int2bin($d),
+            'p' => $this->_math_obj->int2bin($p),
+            'q' => $this->_math_obj->int2bin($q),
+            'dmp1' => $this->_math_obj->int2bin($dmp1),
+            'dmq1' => $this->_math_obj->int2bin($dmq1),
+            'iqmp' => $this->_math_obj->int2bin($iqmp),
+        );
+
+        $n = $this->_attrs['n'];
+        $e = $this->_attrs['e'];
+        $d = $this->_attrs['d'];
+
+        // try to create public key object
+        $obj = &new Crypt_RSA_Key($n, $e, 'public', $this->_math_obj->getWrapperName(), $this->_error_handler);
+        if ($obj->isError()) {
+            // error during creating public object
+            $this->pushError($obj->getLastError());
+            return false;
+        }
+        $this->_public_key = &$obj;
+
+        // try to create private key object
+        $obj = &new Crypt_RSA_Key($n, $d, 'private', $this->_math_obj->getWrapperName(), $this->_error_handler);
+        if ($obj->isError()) {
+            // error during creating private key object
+            $this->pushError($obj->getLastError());
+            return false;
+        }
+        $this->_private_key = &$obj;
+
+        return true; // key pair successfully generated
+    }
+
+    /**
+     * Returns public key from the pair
+     *
+     * @return object  public key object of class Crypt_RSA_Key
+     * @access public
+     */
+    function getPublicKey()
+    {
+        return $this->_public_key;
+    }
+
+    /**
+     * Returns private key from the pair
+     *
+     * @return object   private key object of class Crypt_RSA_Key
+     * @access public
+     */
+    function getPrivateKey()
+    {
+        return $this->_private_key;
+    }
+
+    /**
+     * Sets name of random generator function for key generation.
+     * If parameter is skipped, then sets to default random generator.
+     *
+     * Random generator function must return integer with at least 8 lower
+     * significant bits, which will be used as random values.
+     *
+     * @param string $random_generator name of random generator function
+     *
+     * @return bool                     true on success or false on error
+     * @access public
+     */
+    function setRandomGenerator($random_generator = null)
+    {
+        static $default_random_generator = null;
+
+        if (is_string($random_generator)) {
+            // set user's random generator
+            if (!function_exists($random_generator)) {
+                $this->pushError("can't find random generator function with name [{$random_generator}]");
+                return false;
+            }
+            $this->_random_generator = $random_generator;
+        } else {
+            // set default random generator
+            $this->_random_generator = is_null($default_random_generator) ?
+                ($default_random_generator = create_function('', '$a=explode(" ",microtime());return(int)($a[0]*1000000);')) :
+                $default_random_generator;
+        }
+        return true;
+    }
+
+    /**
+     * Returns length of each key in the key pair
+     *
+     * @return int  bit length of each key in key pair
+     * @access public
+     */
+    function getKeyLength()
+    {
+        return $this->_key_len;
+    }
+
+    /**
+     * Retrieves RSA keypair from PEM-encoded string, containing RSA private key.
+     * Example of such string:
+     * -----BEGIN RSA PRIVATE KEY-----
+     * MCsCAQACBHtvbSECAwEAAQIEeYrk3QIDAOF3AgMAjCcCAmdnAgJMawIDALEk
+     * -----END RSA PRIVATE KEY-----
+     *
+     * Wrapper: Name of math wrapper, which will be used to
+     * perform different operations with big integers.
+     * See contents of Crypt/RSA/Math folder for examples of wrappers.
+     * Read docs/Crypt_RSA/docs/math_wrappers.txt for details.
+     *
+     * @param string $str           PEM-encoded string
+     * @param string $wrapper_name  Wrapper name
+     * @param string $error_handler name of error handler function
+     *
+     * @return Crypt_RSA_KeyPair object on success, PEAR_Error object on error
+     * @access public
+     * @static
+     */
+    function &fromPEMString($str, $wrapper_name = 'default', $error_handler = '')
+    {
+        if (isset($this)) {
+            if ($wrapper_name == 'default') {
+                $wrapper_name = $this->_math_obj->getWrapperName();
+            }
+            if ($error_handler == '') {
+                $error_handler = $this->_error_handler;
+            }
+        }
+        $err_handler = &new Crypt_RSA_ErrorHandler;
+        $err_handler->setErrorHandler($error_handler);
+
+        // search for base64-encoded private key
+        if (!preg_match('/-----BEGIN RSA PRIVATE KEY-----([^-]+)-----END RSA PRIVATE KEY-----/', $str, $matches)) {
+            $err_handler->pushError("can't find RSA private key in the string [{$str}]");
+            return $err_handler->getLastError();
+        }
+
+        // parse private key. It is ASN.1-encoded
+        $str = base64_decode($matches[1]);
+        $pos = 0;
+        $tmp = Crypt_RSA_KeyPair::_ASN1Parse($str, $pos, $err_handler);
+        if ($err_handler->isError()) {
+            return $err_handler->getLastError();
+        }
+        if ($tmp['tag'] != 0x10) {
+            $errstr = sprintf("wrong ASN tag value: 0x%02x. Expected 0x10 (SEQUENCE)", $tmp['tag']);
+            $err_handler->pushError($errstr);
+            return $err_handler->getLastError();
+        }
+
+        // parse ASN.1 SEQUENCE for RSA private key
+        $attr_names = Crypt_RSA_KeyPair::_get_attr_names();
+        $n = sizeof($attr_names);
+        $rsa_attrs = array();
+        for ($i = 0; $i < $n; $i++) {
+            $tmp = Crypt_RSA_KeyPair::_ASN1ParseInt($str, $pos, $err_handler);
+            if ($err_handler->isError()) {
+                return $err_handler->getLastError();
+            }
+            $attr = $attr_names[$i];
+            $rsa_attrs[$attr] = $tmp;
+        }
+
+        // create Crypt_RSA_KeyPair object.
+        $keypair = &new Crypt_RSA_KeyPair($rsa_attrs, $wrapper_name, $error_handler);
+        if ($keypair->isError()) {
+            return $keypair->getLastError();
+        }
+
+        return $keypair;
+    }
+
+    /**
+     * converts keypair to PEM-encoded string, which can be stroed in 
+     * .pem compatible files, contianing RSA private key.
+     *
+     * @return string PEM-encoded keypair on success, false on error
+     * @access public
+     */
+    function toPEMString()
+    {
+        // store RSA private key attributes into ASN.1 string
+        $str = '';
+        $attr_names = $this->_get_attr_names();
+        $n = sizeof($attr_names);
+        $rsa_attrs = $this->_attrs;
+        for ($i = 0; $i < $n; $i++) {
+            $attr = $attr_names[$i];
+            if (!isset($rsa_attrs[$attr])) {
+                $this->pushError("Cannot find value for ASN.1 attribute [$attr]");
+                return false;
+            }
+            $tmp = $rsa_attrs[$attr];
+            $str .= Crypt_RSA_KeyPair::_ASN1StoreInt($tmp);
+        }
+
+        // prepend $str by ASN.1 SEQUENCE (0x10) header
+        $str = Crypt_RSA_KeyPair::_ASN1Store($str, 0x10, true);
+
+        // encode and format PEM string
+        $str = base64_encode($str);
+        $str = chunk_split($str, 64, "\n");
+        return "-----BEGIN RSA PRIVATE KEY-----\n$str-----END RSA PRIVATE KEY-----\n";
+    }
+
+    /**
+     * Compares keypairs in Crypt_RSA_KeyPair objects $this and $key_pair
+     *
+     * @param Crypt_RSA_KeyPair $key_pair  keypair to compare
+     *
+     * @return bool  true, if keypair stored in $this equal to keypair stored in $key_pair
+     * @access public
+     */
+    function isEqual($key_pair)
+    {
+        $attr_names = $this->_get_attr_names();
+        foreach ($attr_names as $attr) {
+            if ($this->_attrs[$attr] != $key_pair->_attrs[$attr]) {
+                return false;
+            }
+        }
+        return true;
+    }
+}
+
+?>