/**
* Break a public or private key down into its constituant components
*
* @access private
* @see _convertPublicKey()
* @see _convertPrivateKey()
* @param String $key
* @param Integer $type
* @return Array
*/
function _parseKey($key, $type)
{
if ($type != self::PUBLIC_FORMAT_RAW && !is_string($key)) {
return false;
}
switch ($type) {
case self::PUBLIC_FORMAT_RAW:
if (!is_array($key)) {
return false;
}
$components = array();
switch (true) {
case isset($key['e']):
$components['publicExponent'] = $key['e']->copy();
break;
case isset($key['exponent']):
$components['publicExponent'] = $key['exponent']->copy();
break;
case isset($key['publicExponent']):
$components['publicExponent'] = $key['publicExponent']->copy();
break;
case isset($key[0]):
$components['publicExponent'] = $key[0]->copy();
}
switch (true) {
case isset($key['n']):
$components['modulus'] = $key['n']->copy();
break;
case isset($key['modulo']):
$components['modulus'] = $key['modulo']->copy();
break;
case isset($key['modulus']):
$components['modulus'] = $key['modulus']->copy();
break;
case isset($key[1]):
$components['modulus'] = $key[1]->copy();
}
return isset($components['modulus']) && isset($components['publicExponent']) ? $components : false;
case self::PRIVATE_FORMAT_PKCS1:
case self::PRIVATE_FORMAT_PKCS8:
case self::PUBLIC_FORMAT_PKCS1:
/* Although PKCS#1 proposes a format that public and private keys can use, encrypting them is
"outside the scope" of PKCS#1. PKCS#1 then refers you to PKCS#12 and PKCS#15 if you're wanting to
protect private keys, however, that's not what OpenSSL* does. OpenSSL protects private keys by adding
two new "fields" to the key - DEK-Info and Proc-Type. These fields are discussed here:
http://tools.ietf.org/html/rfc1421#section-4.6.1.1
http://tools.ietf.org/html/rfc1421#section-4.6.1.3
DES-EDE3-CBC as an algorithm, however, is not discussed anywhere, near as I can tell.
DES-CBC and DES-EDE are discussed in RFC1423, however, DES-EDE3-CBC isn't, nor is its key derivation
function. As is, the definitive authority on this encoding scheme isn't the IETF but rather OpenSSL's
own implementation. ie. the implementation *is* the standard and any bugs that may exist in that
implementation are part of the standard, as well.
* OpenSSL is the de facto standard. It's utilized by OpenSSH and other projects */
if (preg_match('#DEK-Info: (.+),(.+)#', $key, $matches)) {
$iv = pack('H*', trim($matches[2]));
$symkey = pack('H*', md5($this->password . substr($iv, 0, 8)));
// symkey is short for symmetric key
$symkey .= pack('H*', md5($symkey . $this->password . substr($iv, 0, 8)));
// remove the Proc-Type / DEK-Info sections as they're no longer needed
$key = preg_replace('#^(?:Proc-Type|DEK-Info): .*#m', '', $key);
$ciphertext = $this->_extractBER($key);
if ($ciphertext === false) {
$ciphertext = $key;
}
switch ($matches[1]) {
case 'AES-256-CBC':
$crypto = new AES();
break;
case 'AES-128-CBC':
$symkey = substr($symkey, 0, 16);
$crypto = new AES();
break;
case 'DES-EDE3-CFB':
$crypto = new TripleDES(Base::MODE_CFB);
break;
case 'DES-EDE3-CBC':
$symkey = substr($symkey, 0, 24);
$crypto = new TripleDES();
break;
case 'DES-CBC':
$crypto = new DES();
break;
default:
return false;
}
$crypto->setKey($symkey);
$crypto->setIV($iv);
$decoded = $crypto->decrypt($ciphertext);
} else {
$decoded = $this->_extractBER($key);
}
if ($decoded !== false) {
$key = $decoded;
}
$components = array();
if (ord($this->_string_shift($key)) != self::ASN1_SEQUENCE) {
return false;
}
if ($this->_decodeLength($key) != strlen($key)) {
return false;
}
$tag = ord($this->_string_shift($key));
/* intended for keys for which OpenSSL's asn1parse returns the following:
0:d=0 hl=4 l= 631 cons: SEQUENCE
4:d=1 hl=2 l= 1 prim: INTEGER :00
7:d=1 hl=2 l= 13 cons: SEQUENCE
9:d=2 hl=2 l= 9 prim: OBJECT :rsaEncryption
20:d=2 hl=2 l= 0 prim: NULL
22:d=1 hl=4 l= 609 prim: OCTET STRING
ie. PKCS8 keys*/
if ($tag == self::ASN1_INTEGER && substr($key, 0, 3) == "0") {
$this->_string_shift($key, 3);
$tag = self::ASN1_SEQUENCE;
}
if ($tag == self::ASN1_SEQUENCE) {
$temp = $this->_string_shift($key, $this->_decodeLength($key));
if (ord($this->_string_shift($temp)) != self::ASN1_OBJECT) {
return false;
}
$length = $this->_decodeLength($temp);
switch ($this->_string_shift($temp, $length)) {
case "*†H†÷\r":
// rsaEncryption
break;
case "*†H†÷\r":
// pbeWithMD5AndDES-CBC
/*
PBEParameter ::= SEQUENCE {
salt OCTET STRING (SIZE(8)),
iterationCount INTEGER }
*/
if (ord($this->_string_shift($temp)) != self::ASN1_SEQUENCE) {
return false;
}
if ($this->_decodeLength($temp) != strlen($temp)) {
return false;
}
$this->_string_shift($temp);
// assume it's an octet string
$salt = $this->_string_shift($temp, $this->_decodeLength($temp));
if (ord($this->_string_shift($temp)) != self::ASN1_INTEGER) {
return false;
}
$this->_decodeLength($temp);
list(, $iterationCount) = unpack('N', str_pad($temp, 4, chr(0), STR_PAD_LEFT));
$this->_string_shift($key);
// assume it's an octet string
$length = $this->_decodeLength($key);
if (strlen($key) != $length) {
return false;
}
$crypto = new DES();
$crypto->setPassword($this->password, 'pbkdf1', 'md5', $salt, $iterationCount);
$key = $crypto->decrypt($key);
if ($key === false) {
return false;
}
return $this->_parseKey($key, self::PRIVATE_FORMAT_PKCS1);
default:
return false;
}
/* intended for keys for which OpenSSL's asn1parse returns the following:
0:d=0 hl=4 l= 290 cons: SEQUENCE
4:d=1 hl=2 l= 13 cons: SEQUENCE
6:d=2 hl=2 l= 9 prim: OBJECT :rsaEncryption
17:d=2 hl=2 l= 0 prim: NULL
19:d=1 hl=4 l= 271 prim: BIT STRING */
$tag = ord($this->_string_shift($key));
// skip over the BIT STRING / OCTET STRING tag
$this->_decodeLength($key);
// skip over the BIT STRING / OCTET STRING length
// "The initial octet shall encode, as an unsigned binary integer wtih bit 1 as the least significant bit, the number of
// unused bits in the final subsequent octet. The number shall be in the range zero to seven."
// -- http://www.itu.int/ITU-T/studygroups/com17/languages/X.690-0207.pdf (section 8.6.2.2)
if ($tag == self::ASN1_BITSTRING) {
$this->_string_shift($key);
}
if (ord($this->_string_shift($key)) != self::ASN1_SEQUENCE) {
return false;
}
if ($this->_decodeLength($key) != strlen($key)) {
return false;
}
$tag = ord($this->_string_shift($key));
}
if ($tag != self::ASN1_INTEGER) {
return false;
}
$length = $this->_decodeLength($key);
$temp = $this->_string_shift($key, $length);
if (strlen($temp) != 1 || ord($temp) > 2) {
$components['modulus'] = new BigInteger($temp, 256);
$this->_string_shift($key);
// skip over self::ASN1_INTEGER
$length = $this->_decodeLength($key);
$components[$type == self::PUBLIC_FORMAT_PKCS1 ? 'publicExponent' : 'privateExponent'] = new BigInteger($this->_string_shift($key, $length), 256);
return $components;
}
if (ord($this->_string_shift($key)) != self::ASN1_INTEGER) {
return false;
}
$length = $this->_decodeLength($key);
$components['modulus'] = new BigInteger($this->_string_shift($key, $length), 256);
$this->_string_shift($key);
$length = $this->_decodeLength($key);
$components['publicExponent'] = new BigInteger($this->_string_shift($key, $length), 256);
$this->_string_shift($key);
$length = $this->_decodeLength($key);
$components['privateExponent'] = new BigInteger($this->_string_shift($key, $length), 256);
$this->_string_shift($key);
$length = $this->_decodeLength($key);
$components['primes'] = array(1 => new BigInteger($this->_string_shift($key, $length), 256));
$this->_string_shift($key);
$length = $this->_decodeLength($key);
$components['primes'][] = new BigInteger($this->_string_shift($key, $length), 256);
$this->_string_shift($key);
$length = $this->_decodeLength($key);
$components['exponents'] = array(1 => new BigInteger($this->_string_shift($key, $length), 256));
$this->_string_shift($key);
$length = $this->_decodeLength($key);
$components['exponents'][] = new BigInteger($this->_string_shift($key, $length), 256);
$this->_string_shift($key);
$length = $this->_decodeLength($key);
$components['coefficients'] = array(2 => new BigInteger($this->_string_shift($key, $length), 256));
if (!empty($key)) {
if (ord($this->_string_shift($key)) != self::ASN1_SEQUENCE) {
return false;
}
$this->_decodeLength($key);
while (!empty($key)) {
if (ord($this->_string_shift($key)) != self::ASN1_SEQUENCE) {
return false;
}
$this->_decodeLength($key);
$key = substr($key, 1);
$length = $this->_decodeLength($key);
$components['primes'][] = new BigInteger($this->_string_shift($key, $length), 256);
$this->_string_shift($key);
$length = $this->_decodeLength($key);
$components['exponents'][] = new BigInteger($this->_string_shift($key, $length), 256);
$this->_string_shift($key);
$length = $this->_decodeLength($key);
$components['coefficients'][] = new BigInteger($this->_string_shift($key, $length), 256);
}
}
return $components;
case self::PUBLIC_FORMAT_OPENSSH:
$parts = explode(' ', $key, 3);
$key = isset($parts[1]) ? base64_decode($parts[1]) : false;
if ($key === false) {
return false;
}
$comment = isset($parts[2]) ? $parts[2] : false;
$cleanup = substr($key, 0, 11) == "ssh-rsa";
if (strlen($key) <= 4) {
return false;
}
extract(unpack('Nlength', $this->_string_shift($key, 4)));
$publicExponent = new BigInteger($this->_string_shift($key, $length), -256);
if (strlen($key) <= 4) {
return false;
}
extract(unpack('Nlength', $this->_string_shift($key, 4)));
$modulus = new BigInteger($this->_string_shift($key, $length), -256);
if ($cleanup && strlen($key)) {
if (strlen($key) <= 4) {
return false;
}
extract(unpack('Nlength', $this->_string_shift($key, 4)));
$realModulus = new BigInteger($this->_string_shift($key, $length), -256);
return strlen($key) ? false : array('modulus' => $realModulus, 'publicExponent' => $modulus, 'comment' => $comment);
} else {
return strlen($key) ? false : array('modulus' => $modulus, 'publicExponent' => $publicExponent, 'comment' => $comment);
}
// http://www.w3.org/TR/xmldsig-core/#sec-RSAKeyValue
// http://en.wikipedia.org/wiki/XML_Signature
// http://www.w3.org/TR/xmldsig-core/#sec-RSAKeyValue
// http://en.wikipedia.org/wiki/XML_Signature
case self::PRIVATE_FORMAT_XML:
case self::PUBLIC_FORMAT_XML:
$this->components = array();
$xml = xml_parser_create('UTF-8');
xml_set_object($xml, $this);
xml_set_element_handler($xml, '_start_element_handler', '_stop_element_handler');
xml_set_character_data_handler($xml, '_data_handler');
// add <xml></xml> to account for "dangling" tags like <BitStrength>...</BitStrength> that are sometimes added
if (!xml_parse($xml, '<xml>' . $key . '</xml>')) {
return false;
}
return isset($this->components['modulus']) && isset($this->components['publicExponent']) ? $this->components : false;
// from PuTTY's SSHPUBK.C
// from PuTTY's SSHPUBK.C
case self::PRIVATE_FORMAT_PUTTY:
$components = array();
$key = preg_split('#\\r\\n|\\r|\\n#', $key);
$type = trim(preg_replace('#PuTTY-User-Key-File-2: (.+)#', '$1', $key[0]));
if ($type != 'ssh-rsa') {
return false;
}
$encryption = trim(preg_replace('#Encryption: (.+)#', '$1', $key[1]));
$comment = trim(preg_replace('#Comment: (.+)#', '$1', $key[2]));
$publicLength = trim(preg_replace('#Public-Lines: (\\d+)#', '$1', $key[3]));
$public = base64_decode(implode('', array_map('trim', array_slice($key, 4, $publicLength))));
$public = substr($public, 11);
extract(unpack('Nlength', $this->_string_shift($public, 4)));
$components['publicExponent'] = new BigInteger($this->_string_shift($public, $length), -256);
extract(unpack('Nlength', $this->_string_shift($public, 4)));
$components['modulus'] = new BigInteger($this->_string_shift($public, $length), -256);
$privateLength = trim(preg_replace('#Private-Lines: (\\d+)#', '$1', $key[$publicLength + 4]));
$private = base64_decode(implode('', array_map('trim', array_slice($key, $publicLength + 5, $privateLength))));
switch ($encryption) {
case 'aes256-cbc':
$symkey = '';
$sequence = 0;
while (strlen($symkey) < 32) {
$temp = pack('Na*', $sequence++, $this->password);
$symkey .= pack('H*', sha1($temp));
}
$symkey = substr($symkey, 0, 32);
$crypto = new AES();
}
if ($encryption != 'none') {
$crypto->setKey($symkey);
$crypto->disablePadding();
$private = $crypto->decrypt($private);
if ($private === false) {
return false;
}
}
extract(unpack('Nlength', $this->_string_shift($private, 4)));
if (strlen($private) < $length) {
return false;
}
$components['privateExponent'] = new BigInteger($this->_string_shift($private, $length), -256);
extract(unpack('Nlength', $this->_string_shift($private, 4)));
if (strlen($private) < $length) {
return false;
}
$components['primes'] = array(1 => new BigInteger($this->_string_shift($private, $length), -256));
extract(unpack('Nlength', $this->_string_shift($private, 4)));
if (strlen($private) < $length) {
return false;
}
$components['primes'][] = new BigInteger($this->_string_shift($private, $length), -256);
$temp = $components['primes'][1]->subtract($this->one);
$components['exponents'] = array(1 => $components['publicExponent']->modInverse($temp));
$temp = $components['primes'][2]->subtract($this->one);
$components['exponents'][] = $components['publicExponent']->modInverse($temp);
extract(unpack('Nlength', $this->_string_shift($private, 4)));
if (strlen($private) < $length) {
return false;
}
$components['coefficients'] = array(2 => new BigInteger($this->_string_shift($private, $length), -256));
return $components;
}
}
