/lib/SpotSeclibToOpenSsl.php

<?php

/*

 * Utility classe om RSA signatures te laten verifieeren door OpenSSL ipv

 * Crypt/RSA, dit is een keer of 100 sneller

 */

class SpotSeclibToOpenSsl {

	/*

	 * Geinitialiseerde public key cache gebruiken? Is enkel beschikbaar voor

	 * de OpenSSL library

	 */

	private $_pubKeyCache = array();



	function verify($rsaKey, $toCheck, $signature, $useCache) {

		if (isset($this->_pubKeyCache[$rsaKey['modulo'] . $rsaKey['exponent']])) {

			$openSslPubKey = $this->_pubKeyCache[$rsaKey['modulo'] . $rsaKey['exponent']];

			$verified = openssl_verify($toCheck, $signature, $openSslPubKey);

		} else {

			# Initialize the public key to verify with

			$pubKey['n'] = base64_decode($rsaKey['modulo']);

			$pubKey['e'] = base64_decode($rsaKey['exponent']);



			$openSslPubKey = openssl_get_publickey($this->seclibToOpenSsl($pubKey));

			$verified = openssl_verify($toCheck, $signature, $openSslPubKey);

			

			# Moeten we de resource cachen ipv vrijgeven?

			if ($useCache) {

				$this->_pubKeyCache[$rsaKey['modulo'] . $rsaKey['exponent']] = $openSslPubKey;

			} else {

				openssl_free_key($openSslPubKey);

			} # else

		} # else

		

		return $verified;

	} # verify



	function _getOidElementLength($component) {

		# Code copied from

		#   http://chaosinmotion.com/wiki/index.php?title=ASN.1_Library

        if ($component < 0) return 10;               // Full 64 bits takes 10*7 bits to encode

        $l = 1;

        for ($i = 1; $i < 9; ++$i) {

            $l <<= 7;

            if ($component < $l) break;

        }

        return $i;

	} 

	

	function _encodeObjectId($vals) {

		$return = array();

		

		$return[] = 40 * $vals[0] + $vals[1];

		$valCount = count($vals);

		for($i = 2; $i < $valCount; $i++) {

			# Code copied from

			#   http://chaosinmotion.com/wiki/index.php?title=ASN.1_Library

			$v = $vals[$i];

			$len = $this->_getOIDElementLength($v);

			

			for ($j = $len-1; $j > 0; --$j) {

				$m = 0x0080 | (0x007F & ($v >> ($j * 7)));

				$return[] = (int) $m;

			}

			$return[] = (int)(0x007F & $v);

		}



		return $return;

	} # _encodeObjectId





	function seclibToOpenSsl($pubKey) {

		/* 

		 * Structuur van de OpenSSL publickey is als volgt:

		 *

		 * - Sequence

		 * +- Sequence

		 * ++- Object identifier die de RSA key weergeeft (1.2.840.113549.1.1.1)

		 * ++- NULL

		 * +- Bit String

		 * ++- Sequence

		 * +++- Integer

		 * +++- Integer

		 *

		 * Dit willen we nabootsen met deze encoding

		 */

		$publicExponent = $pubKey['e'];

		$modulus = $pubKey['n'];

		$components = array(

			'modulus' => pack('Ca*a*', CRYPT_RSA_ASN1_INTEGER, $this->_encodeLength(strlen($modulus)), $modulus),

			'publicExponent' => pack('Ca*a*', CRYPT_RSA_ASN1_INTEGER, $this->_encodeLength(strlen($publicExponent)), $publicExponent)

		);



		/* 

		 * First encoden we de keys in een bitstring 

		 */		 

		$encodedKeys = pack('Ca*a*a*',

					CRYPT_RSA_ASN1_SEQUENCE, 		 # Sequence

					$this->_encodeLength(strlen($components['modulus']) + strlen($components['publicExponent'])),

					$components['modulus'], 

					$components['publicExponent']

        );

		$encodedKeys = pack('Ca*Ca*',

					0x03, 		# 0x03 means BIT STRING

					$this->_encodeLength(strlen($encodedKeys) + 1), # add 1 voor de 0 unused bits

					0,

					$encodedKeys

		);

		

		/*

		 * Nu creeeren we de type header

		 *

		 * We kunnen de rsaIdentifier berekenen, maar omdat dat toch nooit verandert, 

		 * zetten we de berekening klaar. 

		 * Code om te berekenen:

		 *      $rsaIdentifier = $this->_encodeObjectId(array(1,2,840,113549,1,1,1)); 	// Magic value of RSA

		 *

		 *		$encryptionType = pack('Ca*',

		 *				0x06,		# ASN.1 OBJECT IDENTIFIER

		 *				$this->_encodeLength(count($rsaIdentifier))

		 *		);

		 *		$rsaIdentifierCount = count($rsaIdentifier);

		 *		for($i = 0; $i < $rsaIdentifierCount; $i++) {	

		 *			$encryptionType .= chr($rsaIdentifier[$i]);

		 *		} # foreach

		 *

		 *

		 *		# de encryption type header wordt geappend met een ASN.1 NULL

		 * 		$encryptionType .= pack('CC',

		 *					0x05,			# ASN.1 NULL

		 *					0

		 *		);

		 *

		 *		# en de encryptiontype pakken we in in een sequence

		 *		$encryptionType = pack('Ca*a*',

		 *			CRYPT_RSA_ASN1_SEQUENCE, 		 # Sequence

		 *			$this->_encodeLength(strlen($encryptionType)),

		 *			$encryptionType

		 *		);

		 */

		$encryptionType = "\x30\xd\x6\x9\x2a\x86\x48\x86\xf7\xd\x1\x1\x1\x5\x0";

		

		# en ook dit alles pakken we in een sequence in

		$endResult = pack('Ca*a*',

					CRYPT_RSA_ASN1_SEQUENCE, 		 # Sequence

					$this->_encodeLength(15 + strlen($encodedKeys)), # 15 == strlen($encryptionType)

					$encryptionType . $encodedKeys

		);

		

		return "-----BEGIN PUBLIC KEY-----\n" . 

				chunk_split(base64_encode($endResult), 64) .

				"-----END PUBLIC KEY-----\n";

	} # seclibToOpenSsl



    /**

	 *

	 * From phpSeclib library

	 *

     * 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 ?? 8.1.3} for more information.

     *

     * @access private

     * @param Integer $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);

    }

	

} # SpotSeclibToOpenSsl