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<?php
require_once "Crypt/RSA.php";
class Services_Signing_Openssl extends Services_Signing_Base {
/*
* Public key cache prevent us to acually decode and call OpenSSL
* to create an OpenSSL handle to the public key, saving CPU cycles
*/
private $_pubKeyCache = array();
/*
* Overwrite private constructor
*/
public function __construct() {
} # ctor
/*
* Actually validates the RSA signature
*/
protected function checkRsaSignature($toCheck, $signature, $rsaKey, $useCache) {
# First decode the signature
$signature = base64_decode($signature);
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, $openSslPubKey);
# Keep caching the resource?
if ($useCache) {
$this->_pubKeyCache[$rsaKey['modulo'] . $rsaKey['exponent']] = $openSslPubKey;
} else {
openssl_free_key($openSslPubKey);
} # else
} # else
return $verified;
} # checkRsaSignature
/*
* Creates a public and private key
*/
public function createPrivateKey($sslCnfPath) {
$rsa = new Crypt_RSA();
$rsa->setSignatureMode(CRYPT_RSA_SIGNATURE_PKCS1);
$opensslPrivKey = openssl_pkey_new(array('private_key_bits' => 1024, 'config' => $sslCnfPath));
openssl_pkey_export($opensslPrivKey, $privateKey, null, array('config' => $sslCnfPath));
$publicKey = openssl_pkey_get_details($opensslPrivKey);
$publicKey = $publicKey['key'];
openssl_free_key($opensslPrivKey);
return array('public' => $publicKey,
'private' => $privateKey);
} # createPrivateKey
/*
* Helper function for parsing ASN.1
*/
function _getOidElementLength($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 $i;
}
/*
* Helper function for parsing ASN.1
*/
function _encodeObjectId($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 $return;
} # _encodeObjectId
/*
* Helper function for parsing ASN.1
*/
function seclibToOpenSsl($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 ยง 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);
}
} # Services_Signing_Openssl
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