Authentication.php

<?php

require './PasswordHash.php';

class Authentication {
    private $db;
    
    // Base-2 logarithm of the iteration count used for password stretching
    private $hash_cost_log2 = 8;
    
    // Do we require the hashes to be portable to older systems (less secure)?
    private $hash_portable = FALSE;
    
    public function __construct(PDO $db) {
        $this->db = $db;
        $db->setAttribute(PDO::ATTR_DEFAULT_FETCH_MODE, PDO::FETCH_ASSOC);
        $db->setAttribute(PDO::ATTR_EMULATE_PREPARES, true);
        $db->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
        $db->exec("CREATE TABLE IF NOT EXISTS users (Id INTEGER PRIMARY KEY, username TEXT NOT NULL UNIQUE, hash TEXT NOT NULL)");
        $this->hasher = new PasswordHash($this->hash_cost_log2, $this->hash_portable);
    }
    
    public function create($username, $password) {
        $hash = $this->hasher->HashPassword($password);
        if (strlen($hash) < 20)
	        fail('Failed to hash new password');

        $placeholders = array($username, $hash);
        $stmt = $this->db->prepare("INSERT OR IGNORE INTO users (username, hash) VALUES (?, ?)");
        $stmt->execute($placeholders);
        return $stmt->rowCount() == 1;
    }
    
    public function login($username, $password) {
        $placeholders = array($username);
        $stmt = $this->db->prepare("SELECT hash FROM users WHERE username = ?");
        $stmt->execute($placeholders);
        $row = $stmt->fetch();
        if ($this->hasher->CheckPassword($password, $row['hash'])) {
            return true;
	    } else {
	        return false;
	    }
    }
}

AuthenticationTest.php

<?php

require('./Authentication.php');

class AuthenticationTest extends PHPUnit_Framework_TestCase {
    protected $authentication;
    
    protected function setUp() {
        $db = new PDO('sqlite::memory:');
        $this->authentication = new Authentication($db);
    }
    
    public function testAddingAccountWhichDoesNotYetExist() {
        $ok = $this->authentication->create("alfred", "westerveld");
        $this->assertEquals(true, $ok);
    }
    
    public function testAddingAccountTwice() {
        $ok = $this->authentication->create("alfred", "westerveld");
        $this->assertEquals(true, $ok);
        $ok = $this->authentication->create("alfred", "westerveld");
        $this->assertEquals(false, $ok);
    }
    
    public function testLoginUserWhichDoesNotExist() {
        $ok = $this->authentication->login("alfred", "westerveld");
        $this->assertEquals(false, $ok);
    }
    
    public function testLoginUserWhichDoesExist() {
        $ok = $this->authentication->create("alfred", "westerveld");
        $ok = $this->authentication->login("alfred", "westerveld");
        $this->assertEquals(true, $ok);
    }
}

PasswordHash.php

<?php
#
# Portable PHP password hashing framework.
#
# Version 0.3 / genuine.
#
# Written by Solar Designer <solar at openwall.com> in 2004-2006 and placed in
# the public domain.  Revised in subsequent years, still public domain.
#
# There's absolutely no warranty.
#
# The homepage URL for this framework is:
#
#	http://www.openwall.com/phpass/
#
# Please be sure to update the Version line if you edit this file in any way.
# It is suggested that you leave the main version number intact, but indicate
# your project name (after the slash) and add your own revision information.
#
# Please do not change the "private" password hashing method implemented in
# here, thereby making your hashes incompatible.  However, if you must, please
# change the hash type identifier (the "$P$") to something different.
#
# Obviously, since this code is in the public domain, the above are not
# requirements (there can be none), but merely suggestions.
#
class PasswordHash {
	var $itoa64;
	var $iteration_count_log2;
	var $portable_hashes;
	var $random_state;

	function PasswordHash($iteration_count_log2, $portable_hashes)
	{
		$this->itoa64 = './0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz';

		if ($iteration_count_log2 < 4 || $iteration_count_log2 > 31)
			$iteration_count_log2 = 8;
		$this->iteration_count_log2 = $iteration_count_log2;

		$this->portable_hashes = $portable_hashes;

		$this->random_state = microtime();
		if (function_exists('getmypid'))
			$this->random_state .= getmypid();
	}

	function get_random_bytes($count)
	{
		$output = '';
		if (is_readable('/dev/urandom') &&
		    ($fh = @fopen('/dev/urandom', 'rb'))) {
			$output = fread($fh, $count);
			fclose($fh);
		}

		if (strlen($output) < $count) {
			$output = '';
			for ($i = 0; $i < $count; $i += 16) {
				$this->random_state =
				    md5(microtime() . $this->random_state);
				$output .=
				    pack('H*', md5($this->random_state));
			}
			$output = substr($output, 0, $count);
		}

		return $output;
	}

	function encode64($input, $count)
	{
		$output = '';
		$i = 0;
		do {
			$value = ord($input[$i++]);
			$output .= $this->itoa64[$value & 0x3f];
			if ($i < $count)
				$value |= ord($input[$i]) << 8;
			$output .= $this->itoa64[($value >> 6) & 0x3f];
			if ($i++ >= $count)
				break;
			if ($i < $count)
				$value |= ord($input[$i]) << 16;
			$output .= $this->itoa64[($value >> 12) & 0x3f];
			if ($i++ >= $count)
				break;
			$output .= $this->itoa64[($value >> 18) & 0x3f];
		} while ($i < $count);

		return $output;
	}

	function gensalt_private($input)
	{
		$output = '$P$';
		$output .= $this->itoa64[min($this->iteration_count_log2 +
			((PHP_VERSION >= '5') ? 5 : 3), 30)];
		$output .= $this->encode64($input, 6);

		return $output;
	}

	function crypt_private($password, $setting)
	{
		$output = '*0';
		if (substr($setting, 0, 2) == $output)
			$output = '*1';

		$id = substr($setting, 0, 3);
		# We use "$P$", phpBB3 uses "$H$" for the same thing
		if ($id != '$P$' && $id != '$H$')
			return $output;

		$count_log2 = strpos($this->itoa64, $setting[3]);
		if ($count_log2 < 7 || $count_log2 > 30)
			return $output;

		$count = 1 << $count_log2;

		$salt = substr($setting, 4, 8);
		if (strlen($salt) != 8)
			return $output;

		# We're kind of forced to use MD5 here since it's the only
		# cryptographic primitive available in all versions of PHP
		# currently in use.  To implement our own low-level crypto
		# in PHP would result in much worse performance and
		# consequently in lower iteration counts and hashes that are
		# quicker to crack (by non-PHP code).
		if (PHP_VERSION >= '5') {
			$hash = md5($salt . $password, TRUE);
			do {
				$hash = md5($hash . $password, TRUE);
			} while (--$count);
		} else {
			$hash = pack('H*', md5($salt . $password));
			do {
				$hash = pack('H*', md5($hash . $password));
			} while (--$count);
		}

		$output = substr($setting, 0, 12);
		$output .= $this->encode64($hash, 16);

		return $output;
	}

	function gensalt_extended($input)
	{
		$count_log2 = min($this->iteration_count_log2 + 8, 24);
		# This should be odd to not reveal weak DES keys, and the
		# maximum valid value is (2**24 - 1) which is odd anyway.
		$count = (1 << $count_log2) - 1;

		$output = '_';
		$output .= $this->itoa64[$count & 0x3f];
		$output .= $this->itoa64[($count >> 6) & 0x3f];
		$output .= $this->itoa64[($count >> 12) & 0x3f];
		$output .= $this->itoa64[($count >> 18) & 0x3f];

		$output .= $this->encode64($input, 3);

		return $output;
	}

	function gensalt_blowfish($input)
	{
		# This one needs to use a different order of characters and a
		# different encoding scheme from the one in encode64() above.
		# We care because the last character in our encoded string will
		# only represent 2 bits.  While two known implementations of
		# bcrypt will happily accept and correct a salt string which
		# has the 4 unused bits set to non-zero, we do not want to take
		# chances and we also do not want to waste an additional byte
		# of entropy.
		$itoa64 = './ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789';

		$output = '$2a$';
		$output .= chr(ord('0') + $this->iteration_count_log2 / 10);
		$output .= chr(ord('0') + $this->iteration_count_log2 % 10);
		$output .= '$';

		$i = 0;
		do {
			$c1 = ord($input[$i++]);
			$output .= $itoa64[$c1 >> 2];
			$c1 = ($c1 & 0x03) << 4;
			if ($i >= 16) {
				$output .= $itoa64[$c1];
				break;
			}

			$c2 = ord($input[$i++]);
			$c1 |= $c2 >> 4;
			$output .= $itoa64[$c1];
			$c1 = ($c2 & 0x0f) << 2;

			$c2 = ord($input[$i++]);
			$c1 |= $c2 >> 6;
			$output .= $itoa64[$c1];
			$output .= $itoa64[$c2 & 0x3f];
		} while (1);

		return $output;
	}

	function HashPassword($password)
	{
		$random = '';

		if (CRYPT_BLOWFISH == 1 && !$this->portable_hashes) {
			$random = $this->get_random_bytes(16);
			$hash =
			    crypt($password, $this->gensalt_blowfish($random));
			if (strlen($hash) == 60)
				return $hash;
		}

		if (CRYPT_EXT_DES == 1 && !$this->portable_hashes) {
			if (strlen($random) < 3)
				$random = $this->get_random_bytes(3);
			$hash =
			    crypt($password, $this->gensalt_extended($random));
			if (strlen($hash) == 20)
				return $hash;
		}

		if (strlen($random) < 6)
			$random = $this->get_random_bytes(6);
		$hash =
		    $this->crypt_private($password,
		    $this->gensalt_private($random));
		if (strlen($hash) == 34)
			return $hash;

		# Returning '*' on error is safe here, but would _not_ be safe
		# in a crypt(3)-like function used _both_ for generating new
		# hashes and for validating passwords against existing hashes.
		return '*';
	}

	function CheckPassword($password, $stored_hash)
	{
		$hash = $this->crypt_private($password, $stored_hash);
		if ($hash[0] == '*')
			$hash = crypt($password, $stored_hash);

		return $hash == $stored_hash;
	}
}

?>