/**
* 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;
}
