RSA: move key format handling to plugins

phpseclib/Crypt/RSA/OpenSSH.php

@@ -0,0 +1,142 @@
+<?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 phpseclib\Math\BigInteger;
+
+/**
+ * XML 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 $comment
+     */
+    static function setEncryptionAlgorithm($comment)
+    {
+        self::$comment = $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 = '')
+    {
+       $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) == "\0\0\0\7ssh-rsa";
+
+       if (strlen($key) <= 4) {
+           return false;
+       }
+       extract(unpack('Nlength', self::_string_shift($key, 4)));
+       $publicExponent = new BigInteger(self::_string_shift($key, $length), -256);
+       if (strlen($key) <= 4) {
+           return false;
+       }
+       extract(unpack('Nlength', self::_string_shift($key, 4)));
+       $modulus = new BigInteger(self::_string_shift($key, $length), -256);
+
+       if ($cleanup && strlen($key)) {
+           if (strlen($key) <= 4) {
+               return false;
+           }
+           extract(unpack('Nlength', self::_string_shift($key, 4)));
+           $realModulus = new BigInteger(self::_string_shift($key, $length), -256);
+           return strlen($key) ? false : array(
+               'isPublicKey' => true,
+               'modulus' => $realModulus,
+               'publicExponent' => $modulus,
+               'comment' => $comment
+           );
+       } else {
+           return strlen($key) ? false : 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
+     */
+    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;
+    }
+}