PasswordHash.php

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<?php
#
# 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() . uniqid(rand(), TRUE); // removed getmypid() for compatibility reasons
        }

        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;
        }
}