From 04241a5ccbf839dee953d7e47c894d5c8141f7ee Mon Sep 17 00:00:00 2001
From: Kevin Chabowski <kevin@kch42.de>
Date: Thu, 25 Aug 2011 00:03:31 +0200
Subject: Added a fairly secure password hashing method.

---
 ratatoeskr/sys/models.php |  6 ++--
 ratatoeskr/sys/pwhash.php | 74 +++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 77 insertions(+), 3 deletions(-)
 create mode 100644 ratatoeskr/sys/pwhash.php

diff --git a/ratatoeskr/sys/models.php b/ratatoeskr/sys/models.php
index 4448266..cd327e1 100644
--- a/ratatoeskr/sys/models.php
+++ b/ratatoeskr/sys/models.php
@@ -48,9 +48,9 @@ class User
 	/*
 	 * Variables: Public class properties
 	 * 
-	 * $username - The username
-	 * $pwhash   - SHA1-Hash of the password
-	 * $mail     - E-Mail-address
+	 * $username - The username.
+	 * $pwhash   - <PasswordHash> of the password.
+	 * $mail     - E-Mail-address.
 	 * $fullname - The full name of the user.
 	 * $language - Users language
 	 */
diff --git a/ratatoeskr/sys/pwhash.php b/ratatoeskr/sys/pwhash.php
new file mode 100644
index 0000000..69ec837
--- /dev/null
+++ b/ratatoeskr/sys/pwhash.php
@@ -0,0 +1,74 @@
+<?php
+/*
+ * File: ratatoeskr/sys/pwhash.php
+ * 
+ * Hashing passwords
+ * 
+ * License:
+ * This file is part of Ratatöskr.
+ * Ratatöskr is licensed unter the MIT / X11 License.
+ * See "ratatoeskr/licenses/ratatoeskr" for more information.
+ */
+
+/*
+ * Class:PasswordHash
+ * Contains static functions for password hashes.
+ * Is just used as a namespace, can not be created.
+ * 
+ * It should be fairly difficult to break these salted hashes via bruteforce attacks.
+ */
+class PasswordHash
+{
+	private function __construct() {} /* Prevent construction */
+	
+	private static $saltlen_min = 20;
+	private static $saltlen_max = 30;
+	private static $iterations_min = 5;
+	private static $iterations_max = 10;
+	
+	private static function hash($data, $salt, $iterations)
+	{
+		$hash = $data . $salt;
+		for($i = $iterations ;$i--;)
+			$hash = sha1($data . $hash . $salt, (bool) $i);
+		return $iterations . '$' . bin2hex($salt) . '$' . $hash;
+	}
+	
+	/*
+	 * Function: create
+	 * Create a password hash string.
+	 * 
+	 * Parameters:
+	 * 	$password - The password (or other data) to hash.
+	 * 
+	 * Returns:
+	 * 	The salted hash as a string.
+	 */
+	public static function create($password)
+	{
+		$salt = "";
+		$saltlen = mt_rand(self::$saltlen_min, self::$saltlen_max);
+		for($i = 0; $i < $saltlen; $i++)
+			$salt .= chr(mt_rand(0,255));
+		return self::hash($password, $salt, mt_rand(self::$iterations_min, self::$iterations_max));
+	}
+	
+	/*
+	 * Function: validate
+	 * Validate a salted hash.
+	 * 
+	 * Parameters:
+	 * 	$password - The password to test.
+	 * 	$pwhash   - The hash to test against.
+	 * 
+	 * Returns:
+	 * 	True, if $password was correct, False otherwise.
+	 */
+	public static function validate($password, $pwhash)
+	{
+		list($iterations, $hexsalt, $hash) = explode('$', $pwhash);
+		return self::hash($password, pack("H*", $hexsalt), $iterations) == $pwhash;
+	}
+}
+
+?>
-- 
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