gnu-social/extlib/phpseclib/Crypt/RSA/OpenSSH.php

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<?php
/**
* OpenSSH Formatted RSA Key Handler
*
* PHP version 5
*
* Place in $HOME/.ssh/authorized_keys
*
* @category Crypt
* @package RSA
* @author Jim Wigginton <terrafrost@php.net>
* @copyright 2015 Jim Wigginton
* @license http://www.opensource.org/licenses/mit-license.html MIT License
* @link http://phpseclib.sourceforge.net
*/
namespace phpseclib\Crypt\RSA;
use ParagonIE\ConstantTime\Base64;
use phpseclib\Math\BigInteger;
/**
* OpenSSH Formatted RSA Key Handler
*
* @package RSA
* @author Jim Wigginton <terrafrost@php.net>
* @access public
*/
class OpenSSH
{
/**
* Default comment
*
* @var string
* @access private
*/
static $comment = 'phpseclib-generated-key';
/**
* Sets the default comment
*
* @access public
* @param string $comment
*/
static function setComment($comment)
{
self::$comment = str_replace(array("\r", "\n"), '', $comment);
}
/**
* Break a public or private key down into its constituent components
*
* @access public
* @param string $key
* @param string $password optional
* @return array
*/
static function load($key, $password = '')
{
if (!is_string($key)) {
return false;
}
$parts = explode(' ', $key, 3);
$key = isset($parts[1]) ? Base64::decode($parts[1]) : Base64::decode($parts[0]);
if ($key === false) {
return false;
}
$comment = isset($parts[2]) ? $parts[2] : false;
if (substr($key, 0, 11) != "\0\0\0\7ssh-rsa") {
return false;
}
self::_string_shift($key, 11);
if (strlen($key) <= 4) {
return false;
}
extract(unpack('Nlength', self::_string_shift($key, 4)));
if (strlen($key) <= $length) {
return false;
}
$publicExponent = new BigInteger(self::_string_shift($key, $length), -256);
if (strlen($key) <= 4) {
return false;
}
extract(unpack('Nlength', self::_string_shift($key, 4)));
if (strlen($key) != $length) {
return false;
}
$modulus = new BigInteger(self::_string_shift($key, $length), -256);
return array(
'isPublicKey' => true,
'modulus' => $modulus,
'publicExponent' => $publicExponent,
'comment' => $comment
);
}
/**
* Convert a public key to the appropriate format
*
* @access public
* @param \phpseclib\Math\BigInteger $n
* @param \phpseclib\Math\BigInteger $e
* @return string
*/
static function savePublicKey(BigInteger $n, BigInteger $e)
{
$publicExponent = $e->toBytes(true);
$modulus = $n->toBytes(true);
// from <http://tools.ietf.org/html/rfc4253#page-15>:
// string "ssh-rsa"
// mpint e
// mpint n
$RSAPublicKey = pack('Na*Na*Na*', strlen('ssh-rsa'), 'ssh-rsa', strlen($publicExponent), $publicExponent, strlen($modulus), $modulus);
$RSAPublicKey = 'ssh-rsa ' . Base64::encode($RSAPublicKey) . ' ' . self::$comment;
return $RSAPublicKey;
}
/**
* String Shift
*
* Inspired by array_shift
*
* @param string $string
* @param int $index
* @return string
* @access private
*/
static function _string_shift(&$string, $index = 1)
{
$substr = substr($string, 0, $index);
$string = substr($string, $index);
return $substr;
}
}