XMLSecurityKey.php

<?php

class XMLSecurityKey
{
    const TRIPLEDES_CBC = 'http://www.w3.org/2001/04/xmlenc#tripledes-cbc';
    const AES128_CBC = 'http://www.w3.org/2001/04/xmlenc#aes128-cbc';
    const AES192_CBC = 'http://www.w3.org/2001/04/xmlenc#aes192-cbc';
    const AES256_CBC = 'http://www.w3.org/2001/04/xmlenc#aes256-cbc';
    const RSA_1_5 = 'http://www.w3.org/2001/04/xmlenc#rsa-1_5';
    const RSA_OAEP_MGF1P = 'http://www.w3.org/2001/04/xmlenc#rsa-oaep-mgf1p';
    const DSA_SHA1 = 'http://www.w3.org/2000/09/xmldsig#dsa-sha1';
    const RSA_SHA1 = 'http://www.w3.org/2000/09/xmldsig#rsa-sha1';
    const RSA_SHA256 = 'http://www.w3.org/2001/04/xmldsig-more#rsa-sha256';
    const RSA_SHA384 = 'http://www.w3.org/2001/04/xmldsig-more#rsa-sha384';
    const RSA_SHA512 = 'http://www.w3.org/2001/04/xmldsig-more#rsa-sha512';

    private $cryptParams = array();
    public $type = 0;
    public $key = NULL;
    public $passphrase = "";
    public $iv = NULL;
    public $name = NULL;
    public $keyChain = NULL;
    public $isEncrypted = FALSE;
    public $encryptedCtx = NULL;
    public $guid = NULL;

    /**
     * This variable contains the certificate as a string if this key represents an X509-certificate.
     * If this key doesn't represent a certificate, this will be NULL.
     */
    private $x509Certificate = NULL;

    /* This variable contains the certificate thunbprint if we have loaded an X509-certificate. */
    private $X509Thumbprint = NULL;

    public function __construct($type, $params=NULL) {
        srand();
        switch ($type) {
            case (XMLSecurityKey::TRIPLEDES_CBC):
                $this->cryptParams['library'] = 'mcrypt';
                $this->cryptParams['cipher'] = MCRYPT_TRIPLEDES;
                $this->cryptParams['mode'] = MCRYPT_MODE_CBC;
                $this->cryptParams['method'] = 'http://www.w3.org/2001/04/xmlenc#tripledes-cbc';
                $this->cryptParams['keysize'] = 24;
                break;
            case (XMLSecurityKey::AES128_CBC):
                $this->cryptParams['library'] = 'mcrypt';
                $this->cryptParams['cipher'] = MCRYPT_RIJNDAEL_128;
                $this->cryptParams['mode'] = MCRYPT_MODE_CBC;
                $this->cryptParams['method'] = 'http://www.w3.org/2001/04/xmlenc#aes128-cbc';
                $this->cryptParams['keysize'] = 16;
                break;
            case (XMLSecurityKey::AES192_CBC):
                $this->cryptParams['library'] = 'mcrypt';
                $this->cryptParams['cipher'] = MCRYPT_RIJNDAEL_128;
                $this->cryptParams['mode'] = MCRYPT_MODE_CBC;
                $this->cryptParams['method'] = 'http://www.w3.org/2001/04/xmlenc#aes192-cbc';
                $this->cryptParams['keysize'] = 24;
                break;
            case (XMLSecurityKey::AES256_CBC):
                $this->cryptParams['library'] = 'mcrypt';
                $this->cryptParams['cipher'] = MCRYPT_RIJNDAEL_128;
                $this->cryptParams['mode'] = MCRYPT_MODE_CBC;
                $this->cryptParams['method'] = 'http://www.w3.org/2001/04/xmlenc#aes256-cbc';
                $this->cryptParams['keysize'] = 32;
                break;
            case (XMLSecurityKey::RSA_1_5):
                $this->cryptParams['library'] = 'openssl';
                $this->cryptParams['padding'] = OPENSSL_PKCS1_PADDING;
                $this->cryptParams['method'] = 'http://www.w3.org/2001/04/xmlenc#rsa-1_5';
                if (is_array($params) && ! empty($params['type'])) {
                    if ($params['type'] == 'public' || $params['type'] == 'private') {
                        $this->cryptParams['type'] = $params['type'];
                        break;
                    }
                }
                throw new Exception('Certificate "type" (private/public) must be passed via parameters');
                return;
            case (XMLSecurityKey::RSA_OAEP_MGF1P):
                $this->cryptParams['library'] = 'openssl';
                $this->cryptParams['padding'] = OPENSSL_PKCS1_OAEP_PADDING;
                $this->cryptParams['method'] = 'http://www.w3.org/2001/04/xmlenc#rsa-oaep-mgf1p';
                $this->cryptParams['hash'] = NULL;
                if (is_array($params) && ! empty($params['type'])) {
                    if ($params['type'] == 'public' || $params['type'] == 'private') {
                        $this->cryptParams['type'] = $params['type'];
                        break;
                    }
                }
                throw new Exception('Certificate "type" (private/public) must be passed via parameters');
                return;
            case (XMLSecurityKey::RSA_SHA1):
                $this->cryptParams['library'] = 'openssl';
                $this->cryptParams['method'] = 'http://www.w3.org/2000/09/xmldsig#rsa-sha1';
                $this->cryptParams['padding'] = OPENSSL_PKCS1_PADDING;
                if (is_array($params) && ! empty($params['type'])) {
                    if ($params['type'] == 'public' || $params['type'] == 'private') {
                        $this->cryptParams['type'] = $params['type'];
                        break;
                    }
                }
                throw new Exception('Certificate "type" (private/public) must be passed via parameters');
                break;
            case (XMLSecurityKey::RSA_SHA256):
                $this->cryptParams['library'] = 'openssl';
                $this->cryptParams['method'] = 'http://www.w3.org/2001/04/xmldsig-more#rsa-sha256';
                $this->cryptParams['padding'] = OPENSSL_PKCS1_PADDING;
                $this->cryptParams['digest'] = 'SHA256';
                if (is_array($params) && ! empty($params['type'])) {
                    if ($params['type'] == 'public' || $params['type'] == 'private') {
                        $this->cryptParams['type'] = $params['type'];
                        break;
                    }
                }
                throw new Exception('Certificate "type" (private/public) must be passed via parameters');
                break;
            case (XMLSecurityKey::RSA_SHA384):
                $this->cryptParams['library'] = 'openssl';
                $this->cryptParams['method'] = 'http://www.w3.org/2001/04/xmldsig-more#rsa-sha384';
                $this->cryptParams['padding'] = OPENSSL_PKCS1_PADDING;
                $this->cryptParams['digest'] = 'SHA384';
                if (is_array($params) && ! empty($params['type'])) {
                    if ($params['type'] == 'public' || $params['type'] == 'private') {
                        $this->cryptParams['type'] = $params['type'];
                        break;
                    }
                }
            case (XMLSecurityKey::RSA_SHA512):
                $this->cryptParams['library'] = 'openssl';
                $this->cryptParams['method'] = 'http://www.w3.org/2001/04/xmldsig-more#rsa-sha512';
                $this->cryptParams['padding'] = OPENSSL_PKCS1_PADDING;
                $this->cryptParams['digest'] = 'SHA512';
                if (is_array($params) && ! empty($params['type'])) {
                    if ($params['type'] == 'public' || $params['type'] == 'private') {
                        $this->cryptParams['type'] = $params['type'];
                        break;
                    }
                }
            default:
                throw new Exception('Invalid Key Type');
                return;
        }
        $this->type = $type;
    }

    /**
     * Retrieve the key size for the symmetric encryption algorithm..
     *
     * If the key size is unknown, or this isn't a symmetric encryption algorithm,
     * NULL is returned.
     *
     * @return int|NULL  The number of bytes in the key.
     */
    public function getSymmetricKeySize() {
        if (! isset($this->cryptParams['keysize'])) {
            return NULL;
        }
        return $this->cryptParams['keysize'];
    }

    public function generateSessionKey() {
        if (!isset($this->cryptParams['keysize'])) {
            throw new Exception('Unknown key size for type "' . $this->type . '".');
        }
        $keysize = $this->cryptParams['keysize'];

        if (function_exists('openssl_random_pseudo_bytes')) {
            /* We have PHP >= 5.3 - use openssl to generate session key. */
            $key = openssl_random_pseudo_bytes($keysize);
        } else {
            /* Generating random key using iv generation routines */
            $key = mcrypt_create_iv($keysize, MCRYPT_RAND);
        }

        if ($this->type === XMLSecurityKey::TRIPLEDES_CBC) {
            /* Make sure that the generated key has the proper parity bits set.
             * Mcrypt doesn't care about the parity bits, but others may care.
            */
            for ($i = 0; $i < strlen($key); $i++) {
                $byte = ord($key[$i]) & 0xfe;
                $parity = 1;
                for ($j = 1; $j < 8; $j++) {
                    $parity ^= ($byte >> $j) & 1;
                }
                $byte |= $parity;
                $key[$i] = chr($byte);
            }
        }

        $this->key = $key;
        return $key;
    }

    public static function getRawThumbprint($cert) {

        $arCert = explode("\n", $cert);
        $data = '';
        $inData = FALSE;

        foreach ($arCert AS $curData) {
            if (! $inData) {
                if (strncmp($curData, '-----BEGIN CERTIFICATE', 22) == 0) {
                    $inData = TRUE;
                }
            } else {
                if (strncmp($curData, '-----END CERTIFICATE', 20) == 0) {
                    $inData = FALSE;
                    break;
                }
                $data .= trim($curData);
            }
        }

        if (! empty($data)) {
            return strtolower(sha1(base64_decode($data)));
        }

        return NULL;
    }

    public function loadKey($key, $isFile=FALSE, $isCert = FALSE) {
        if ($isFile) {
            $this->key = file_get_contents($key);
        } else {
            $this->key = $key;
        }
        if ($isCert) {
            $this->key = openssl_x509_read($this->key);
            openssl_x509_export($this->key, $str_cert);
            $this->x509Certificate = $str_cert;
            $this->key = $str_cert;
        } else {
            $this->x509Certificate = NULL;
        }
        if ($this->cryptParams['library'] == 'openssl') {
            if ($this->cryptParams['type'] == 'public') {
                if ($isCert) {
                    /* Load the thumbprint if this is an X509 certificate. */
                    $this->X509Thumbprint = self::getRawThumbprint($this->key);
                }
                $this->key = openssl_get_publickey($this->key);
            } else {
                $this->key = openssl_get_privatekey($this->key, $this->passphrase);
            }
        } else if ($this->cryptParams['cipher'] == MCRYPT_RIJNDAEL_128) {
            /* Check key length */
            switch ($this->type) {
                case (XMLSecurityKey::AES256_CBC):
                    if (strlen($this->key) < 25) {
                        throw new Exception('Key must contain at least 25 characters for this cipher');
                    }
                    break;
                case (XMLSecurityKey::AES192_CBC):
                    if (strlen($this->key) < 17) {
                        throw new Exception('Key must contain at least 17 characters for this cipher');
                    }
                    break;
            }
        }
    }

    private function encryptMcrypt($data) {
        $td = mcrypt_module_open($this->cryptParams['cipher'], '', $this->cryptParams['mode'], '');
        $this->iv = mcrypt_create_iv (mcrypt_enc_get_iv_size($td), MCRYPT_RAND);
        mcrypt_generic_init($td, $this->key, $this->iv);
        if ($this->cryptParams['mode'] == MCRYPT_MODE_CBC) {
            $bs = mcrypt_enc_get_block_size($td);
            for ($datalen0=$datalen=strlen($data); (($datalen%$bs)!=($bs-1)); $datalen++)
                $data.=chr(rand(1, 127));
            $data.=chr($datalen-$datalen0+1);
        }
        $encrypted_data = $this->iv.mcrypt_generic($td, $data);
        mcrypt_generic_deinit($td);
        mcrypt_module_close($td);
        return $encrypted_data;
    }

    private function decryptMcrypt($data) {
        $td = mcrypt_module_open($this->cryptParams['cipher'], '', $this->cryptParams['mode'], '');
        $iv_length = mcrypt_enc_get_iv_size($td);

        $this->iv = substr($data, 0, $iv_length);
        $data = substr($data, $iv_length);

        mcrypt_generic_init($td, $this->key, $this->iv);
        $decrypted_data = mdecrypt_generic($td, $data);
        mcrypt_generic_deinit($td);
        mcrypt_module_close($td);
        if ($this->cryptParams['mode'] == MCRYPT_MODE_CBC) {
            $dataLen = strlen($decrypted_data);
            $paddingLength = substr($decrypted_data, $dataLen - 1, 1);
            $decrypted_data = substr($decrypted_data, 0, $dataLen - ord($paddingLength));
        }
        return $decrypted_data;
    }

    private function encryptOpenSSL($data) {
        if ($this->cryptParams['type'] == 'public') {
            if (! openssl_public_encrypt($data, $encrypted_data, $this->key, $this->cryptParams['padding'])) {
                throw new Exception('Failure encrypting Data');
                return;
            }
        } else {
            if (! openssl_private_encrypt($data, $encrypted_data, $this->key, $this->cryptParams['padding'])) {
                throw new Exception('Failure encrypting Data');
                return;
            }
        }
        return $encrypted_data;
    }

    private function decryptOpenSSL($data) {
        if ($this->cryptParams['type'] == 'public') {
            if (! openssl_public_decrypt($data, $decrypted, $this->key, $this->cryptParams['padding'])) {
                throw new Exception('Failure decrypting Data');
                return;
            }
        } else {
            if (! openssl_private_decrypt($data, $decrypted, $this->key, $this->cryptParams['padding'])) {
                throw new Exception('Failure decrypting Data');
                return;
            }
        }
        return $decrypted;
    }

    private function signOpenSSL($data) {
        $algo = OPENSSL_ALGO_SHA1;
        if (! empty($this->cryptParams['digest'])) {
            $algo = $this->cryptParams['digest'];
        }
        if (! openssl_sign ($data, $signature, $this->key, $algo)) {
            throw new Exception('Failure Signing Data: ' . openssl_error_string() . ' - ' . $algo);
            return;
        }
        return $signature;
    }

    private function verifyOpenSSL($data, $signature) {
        $algo = OPENSSL_ALGO_SHA1;
        if (! empty($this->cryptParams['digest'])) {
            $algo = $this->cryptParams['digest'];
        }
        return openssl_verify ($data, $signature, $this->key, $algo);
    }

    public function encryptData($data) {
        switch ($this->cryptParams['library']) {
            case 'mcrypt':
                return $this->encryptMcrypt($data);
                break;
            case 'openssl':
                return $this->encryptOpenSSL($data);
                break;
        }
    }

    public function decryptData($data) {
        switch ($this->cryptParams['library']) {
            case 'mcrypt':
                return $this->decryptMcrypt($data);
                break;
            case 'openssl':
                return $this->decryptOpenSSL($data);
                break;
        }
    }

    public function signData($data) {
        switch ($this->cryptParams['library']) {
            case 'openssl':
                return $this->signOpenSSL($data);
                break;
        }
    }

    public function verifySignature($data, $signature) {
        switch ($this->cryptParams['library']) {
            case 'openssl':
                return $this->verifyOpenSSL($data, $signature);
                break;
        }
    }

    public function getAlgorith() {
        return $this->cryptParams['method'];
    }

    static function makeAsnSegment($type, $string) {
        switch ($type){
            case 0x02:
                if (ord($string) > 0x7f)
                    $string = chr(0).$string;
                break;
            case 0x03:
                $string = chr(0).$string;
                break;
        }

        $length = strlen($string);

        if ($length < 128){
            $output = sprintf("%c%c%s", $type, $length, $string);
        } else if ($length < 0x0100){
            $output = sprintf("%c%c%c%s", $type, 0x81, $length, $string);
        } else if ($length < 0x010000) {
            $output = sprintf("%c%c%c%c%s", $type, 0x82, $length/0x0100, $length%0x0100, $string);
        } else {
            $output = NULL;
        }
        return($output);
    }

    /* Modulus and Exponent must already be base64 decoded */
    static function convertRSA($modulus, $exponent) {
        /* make an ASN publicKeyInfo */
        $exponentEncoding = XMLSecurityKey::makeAsnSegment(0x02, $exponent);
        $modulusEncoding = XMLSecurityKey::makeAsnSegment(0x02, $modulus);
        $sequenceEncoding = XMLSecurityKey:: makeAsnSegment(0x30, $modulusEncoding.$exponentEncoding);
        $bitstringEncoding = XMLSecurityKey::makeAsnSegment(0x03, $sequenceEncoding);
        $rsaAlgorithmIdentifier = pack("H*", "300D06092A864886F70D0101010500");
        $publicKeyInfo = XMLSecurityKey::makeAsnSegment (0x30, $rsaAlgorithmIdentifier.$bitstringEncoding);

        /* encode the publicKeyInfo in base64 and add PEM brackets */
        $publicKeyInfoBase64 = base64_encode($publicKeyInfo);
        $encoding = "-----BEGIN PUBLIC KEY-----\n";
        $offset = 0;
        while ($segment=substr($publicKeyInfoBase64, $offset, 64)){
            $encoding = $encoding.$segment."\n";
            $offset += 64;
        }
        return $encoding."-----END PUBLIC KEY-----\n";
    }

    public function serializeKey($parent) {

    }



    /**
     * Retrieve the X509 certificate this key represents.
     *
     * Will return the X509 certificate in PEM-format if this key represents
     * an X509 certificate.
     *
     * @return  The X509 certificate or NULL if this key doesn't represent an X509-certificate.
     */
    public function getX509Certificate() {
        return $this->x509Certificate;
    }

    /* Get the thumbprint of this X509 certificate.
     *
     * Returns:
     *  The thumbprint as a lowercase 40-character hexadecimal number, or NULL
     *  if this isn't a X509 certificate.
     */
    public function getX509Thumbprint() {
        return $this->X509Thumbprint;
    }


    /**
     * Create key from an EncryptedKey-element.
     *
     * @param DOMElement $element  The EncryptedKey-element.
     * @return XMLSecurityKey  The new key.
     */
    public static function fromEncryptedKeyElement(DOMElement $element) {

        $objenc = new XMLSecEnc();
        $objenc->setNode($element);
        if (! $objKey = $objenc->locateKey()) {
            throw new Exception("Unable to locate algorithm for this Encrypted Key");
        }
        $objKey->isEncrypted = TRUE;
        $objKey->encryptedCtx = $objenc;
        XMLSecEnc::staticLocateKeyInfo($objKey, $element);
        return $objKey;
    }

}