/** * Generate a random string. * * Although microoptimizations are generally discouraged as they impair * readability this function is ripe with * microoptimizations because this function has the potential of being * called a huge number of times. * eg. for RSA key generation. * * @param Integer $length * @return String * @access public */ function crypt_random_string($length) { if (CRYPT_RANDOM_IS_WINDOWS) { // method 1. prior to PHP 5.3 this would call rand() on windows // hence the function_exists('class_alias') call. // ie. class_alias is a function that was introduced in PHP 5.3 if (function_exists('mcrypt_create_iv') && function_exists('class_alias')) { return mcrypt_create_iv($length); } // method 2. openssl_random_pseudo_bytes was introduced in PHP 5.3.0 // but prior to PHP 5.3.4 there was, // to quote <http://php.net/ChangeLog-5.php#5.3.4>, "possible // blocking behavior". as of 5.3.4 // openssl_random_pseudo_bytes and mcrypt_create_iv do the exact // same thing on Windows. ie. they both // call php_win32_get_random_bytes(): // // https://github.com/php/php-src/blob/7014a0eb6d1611151a286c0ff4f2238f92c120d6/ext/openssl/openssl.c#L5008 // https://github.com/php/php-src/blob/7014a0eb6d1611151a286c0ff4f2238f92c120d6/ext/mcrypt/mcrypt.c#L1392 // // php_win32_get_random_bytes() is defined thusly: // // https://github.com/php/php-src/blob/7014a0eb6d1611151a286c0ff4f2238f92c120d6/win32/winutil.c#L80 // // we're calling it, all the same, in the off chance that the mcrypt // extension is not available if (function_exists('openssl_random_pseudo_bytes') && version_compare(PHP_VERSION, '5.3.4', '>=')) { return openssl_random_pseudo_bytes($length); } } else { // method 1. the fastest if (function_exists('openssl_random_pseudo_bytes')) { return openssl_random_pseudo_bytes($length); } // method 2 static $fp = true; if ($fp === true) { // warning's will be output unles the error suppression operator // is used. errors such as // "open_basedir restriction in effect", "Permission denied", // "No such file or directory", etc. $fp = @fopen('/dev/urandom', 'rb'); } if ($fp !== true && $fp !== false) { // surprisingly faster than // !is_bool() or is_resource() return fread($fp, $length); } // method 3. pretty much does the same thing as method 2 per the // following url: // https://github.com/php/php-src/blob/7014a0eb6d1611151a286c0ff4f2238f92c120d6/ext/mcrypt/mcrypt.c#L1391 // surprisingly slower than method 2. maybe that's because // mcrypt_create_iv does a bunch of error checking that we're // not doing. regardless, this'll only be called if this PHP script // couldn't open /dev/urandom due to open_basedir // restrictions or some such if (function_exists('mcrypt_create_iv')) { return mcrypt_create_iv($length, MCRYPT_DEV_URANDOM); } } // at this point we have no choice but to use a pure-PHP CSPRNG // cascade entropy across multiple PHP instances by fixing the session // and collecting all // environmental variables, including the previous session data and the // current session // data. // // mt_rand seeds itself by looking at the PID and the time, both of // which are (relatively) // easy to guess at. linux uses mouse clicks, keyboard timings, etc, as // entropy sources, but // PHP isn't low level to be able to use those as sources and on a web // server there's not likely // going to be a ton of keyboard or mouse action. web servers do have // one thing that we can use // however, a ton of people visiting the website. obviously you don't // want to base your seeding // soley on parameters a potential attacker sends but (1) not everything // in $_SERVER is controlled // by the user and (2) this isn't just looking at the data sent by the // current user - it's based // on the data sent by all users. one user requests the page and a hash // of their info is saved. // another user visits the page and the serialization of their data is // utilized along with the // server envirnment stuff and a hash of the previous http request data // (which itself utilizes // a hash of the session data before that). certainly an attacker should // be assumed to have // full control over his own http requests. he, however, is not going to // have control over // everyone's http requests. static $crypto = false, $v; if ($crypto === false) { // save old session data $old_session_id = session_id(); $old_use_cookies = ini_get('session.use_cookies'); $old_session_cache_limiter = session_cache_limiter(); $_OLD_SESSION = isset($_SESSION) ? $_SESSION : false; if ($old_session_id != '') { session_write_close(); } session_id(1); ini_set('session.use_cookies', 0); session_cache_limiter(''); session_start(); $v = $seed = $_SESSION['seed'] = pack('H*', sha1(serialize($_SERVER) . serialize($_POST) . serialize($_GET) . serialize($_COOKIE) . serialize($GLOBALS) . serialize($_SESSION) . serialize($_OLD_SESSION))); if (!isset($_SESSION['count'])) { $_SESSION['count'] = 0; } $_SESSION['count']++; session_write_close(); // restore old session data if ($old_session_id != '') { session_id($old_session_id); session_start(); ini_set('session.use_cookies', $old_use_cookies); session_cache_limiter($old_session_cache_limiter); } else { if ($_OLD_SESSION !== false) { $_SESSION = $_OLD_SESSION; unset($_OLD_SESSION); } else { unset($_SESSION); } } // in SSH2 a shared secret and an exchange hash are generated // through the key exchange process. // the IV client to server is the hash of that "nonce" with the // letter A and for the encryption key it's the letter C. // if the hash doesn't produce enough a key or an IV that's long // enough concat successive hashes of the // original hash and the current hash. we'll be emulating that. for // more info see the following URL: // // http://tools.ietf.org/html/rfc4253#section-7.2 // // see the is_string($crypto) part for an example of how to expand // the keys $key = pack('H*', sha1($seed . 'A')); $iv = pack('H*', sha1($seed . 'C')); // ciphers are used as per the nist.gov link below. also, see this // link: // // http://en.wikipedia.org/wiki/Cryptographically_secure_pseudorandom_number_generator#Designs_based_on_cryptographic_primitives switch (true) { case phpseclib_resolve_include_path('Crypt/AES.php'): if (!class_exists('Crypt_AES')) { include_once 'AES.php'; } $crypto = new Crypt_AES(CRYPT_AES_MODE_CTR); break; case phpseclib_resolve_include_path('Crypt/Twofish.php'): if (!class_exists('Crypt_Twofish')) { include_once 'Twofish.php'; } $crypto = new Crypt_Twofish(CRYPT_TWOFISH_MODE_CTR); break; case phpseclib_resolve_include_path('Crypt/Blowfish.php'): if (!class_exists('Crypt_Blowfish')) { include_once 'Blowfish.php'; } $crypto = new Crypt_Blowfish(CRYPT_BLOWFISH_MODE_CTR); break; case phpseclib_resolve_include_path('Crypt/TripleDES.php'): if (!class_exists('Crypt_TripleDES')) { include_once 'TripleDES.php'; } $crypto = new Crypt_TripleDES(CRYPT_DES_MODE_CTR); break; case phpseclib_resolve_include_path('Crypt/DES.php'): if (!class_exists('Crypt_DES')) { include_once 'DES.php'; } $crypto = new Crypt_DES(CRYPT_DES_MODE_CTR); break; case phpseclib_resolve_include_path('Crypt/RC4.php'): if (!class_exists('Crypt_RC4')) { include_once 'RC4.php'; } $crypto = new Crypt_RC4(); break; default: user_error('crypt_random_string requires at least one symmetric cipher be loaded'); return false; } $crypto->setKey($key); $crypto->setIV($iv); $crypto->enableContinuousBuffer(); } // return $crypto->encrypt(str_repeat("\0", $length)); // the following is based off of ANSI X9.31: // // http://csrc.nist.gov/groups/STM/cavp/documents/rng/931rngext.pdf // // OpenSSL uses that same standard for it's random numbers: // // http://www.opensource.apple.com/source/OpenSSL/OpenSSL-38/openssl/fips-1.0/rand/fips_rand.c // (do a search for "ANS X9.31 A.2.4") $result = ''; while (strlen($result) < $length) { $i = $crypto->encrypt(microtime()); // strlen(microtime()) == 21 $r = $crypto->encrypt($i ^ $v); // strlen($v) == 20 $v = $crypto->encrypt($r ^ $i); // strlen($r) == 20 $result .= $r; } return substr($result, 0, $length); }
/** * Generate a random value. * * On 32-bit machines, the largest distance that can exist between $min and $max is 2**31. * If $min and $max are farther apart than that then the last ($max - range) numbers. * * Depending on how this is being used, it may be worth while to write a replacement. For example, * a PHP-based web app that stores its data in an SQL database can collect more entropy than this function * can. * * @param optional Integer $min * @param optional Integer $max * @return Integer * @access public */ function crypt_random($min = 0, $max = 0x7fffffff) { if ($min == $max) { return $min; } // see http://en.wikipedia.org/wiki//dev/random // if open_basedir is enabled file_exists() will ouput an "open_basedir restriction in effect" warning, // so we suppress it. if (@file_exists('/dev/urandom')) { static $fp; if (!$fp) { $fp = fopen('/dev/urandom', 'rb'); } extract(unpack('Nrandom', fread($fp, 4))); // say $min = 0 and $max = 3. if we didn't do abs() then we could have stuff like this: // -4 % 3 + 0 = -1, even though -1 < $min return abs($random) % ($max - $min) + $min; } /* Prior to PHP 4.2.0, mt_srand() had to be called before mt_rand() could be called. Prior to PHP 5.2.6, mt_rand()'s automatic seeding was subpar, as elaborated here: http://www.suspekt.org/2008/08/17/mt_srand-and-not-so-random-numbers/ The seeding routine is pretty much ripped from PHP's own internal GENERATE_SEED() macro: http://svn.php.net/viewvc/php/php-src/branches/PHP_5_3_2/ext/standard/php_rand.h?view=markup */ if (version_compare(PHP_VERSION, '5.2.5', '<=')) { static $seeded; if (!isset($seeded)) { $seeded = true; mt_srand(fmod(time() * getmypid(), 0x7fffffff) ^ fmod(1000000 * lcg_value(), 0x7fffffff)); } } static $crypto; // The CSPRNG's Yarrow and Fortuna periodically reseed. This function can be reseeded by hitting F5 // in the browser and reloading the page. if (!isset($crypto)) { $key = $iv = ''; for ($i = 0; $i < 8; $i++) { $key .= pack('n', mt_rand(0, 0xffff)); $iv .= pack('n', mt_rand(0, 0xffff)); } switch (true) { case class_exists('Crypt_AES'): $crypto = new Crypt_AES(CRYPT_AES_MODE_CTR); break; case class_exists('Crypt_TripleDES'): $crypto = new Crypt_TripleDES(CRYPT_DES_MODE_CTR); break; case class_exists('Crypt_DES'): $crypto = new Crypt_DES(CRYPT_DES_MODE_CTR); break; case class_exists('Crypt_RC4'): $crypto = new Crypt_RC4(); break; default: extract(unpack('Nrandom', pack('H*', sha1(mt_rand(0, 0x7fffffff))))); return abs($random) % ($max - $min) + $min; } $crypto->setKey($key); $crypto->setIV($iv); $crypto->enableContinuousBuffer(); } extract(unpack('Nrandom', $crypto->encrypt(""))); return abs($random) % ($max - $min) + $min; }
/** * Generate a random value. * * On 32-bit machines, the largest distance that can exist between $min and $max is 2**31. * If $min and $max are farther apart than that then the last ($max - range) numbers. * * Depending on how this is being used, it may be worth while to write a replacement. For example, * a PHP-based web app that stores its data in an SQL database can collect more entropy than this function * can. * * @param optional Integer $min * @param optional Integer $max * @return Integer * @access public */ function crypt_random($min = 0, $max = 0x7fffffff) { if ($min == $max) { return $min; } if (function_exists('openssl_random_pseudo_bytes')) { // openssl_random_pseudo_bytes() is slow on windows per the following: // http://stackoverflow.com/questions/1940168/openssl-random-pseudo-bytes-is-slow-php if ((PHP_OS & "ßßß") !== 'WIN') { // PHP_OS & "\xDF\xDF\xDF" == strtoupper(substr(PHP_OS, 0, 3)), but a lot faster extract(unpack('Nrandom', openssl_random_pseudo_bytes(4))); return abs($random) % ($max - $min) + $min; } } // see http://en.wikipedia.org/wiki//dev/random static $urandom = true; if ($urandom === true) { // Warning's will be output unles the error suppression operator is used. Errors such as // "open_basedir restriction in effect", "Permission denied", "No such file or directory", etc. $urandom = @fopen('/dev/urandom', 'rb'); } if (!is_bool($urandom)) { extract(unpack('Nrandom', fread($urandom, 4))); // say $min = 0 and $max = 3. if we didn't do abs() then we could have stuff like this: // -4 % 3 + 0 = -1, even though -1 < $min return abs($random) % ($max - $min) + $min; } /* Prior to PHP 4.2.0, mt_srand() had to be called before mt_rand() could be called. Prior to PHP 5.2.6, mt_rand()'s automatic seeding was subpar, as elaborated here: http://www.suspekt.org/2008/08/17/mt_srand-and-not-so-random-numbers/ The seeding routine is pretty much ripped from PHP's own internal GENERATE_SEED() macro: http://svn.php.net/viewvc/php/php-src/tags/php_5_3_2/ext/standard/php_rand.h?view=markup */ if (version_compare(PHP_VERSION, '5.2.5', '<=')) { static $seeded; if (!isset($seeded)) { $seeded = true; mt_srand(fmod(time() * getmypid(), 0x7fffffff) ^ fmod(1000000 * lcg_value(), 0x7fffffff)); } } static $crypto; // The CSPRNG's Yarrow and Fortuna periodically reseed. This function can be reseeded by hitting F5 // in the browser and reloading the page. if (!isset($crypto)) { $key = $iv = ''; for ($i = 0; $i < 8; $i++) { $key .= pack('n', mt_rand(0, 0xffff)); $iv .= pack('n', mt_rand(0, 0xffff)); } switch (true) { case class_exists('Crypt_AES'): $crypto = new Crypt_AES(CRYPT_AES_MODE_CTR); break; case class_exists('Crypt_TripleDES'): $crypto = new Crypt_TripleDES(CRYPT_DES_MODE_CTR); break; case class_exists('Crypt_DES'): $crypto = new Crypt_DES(CRYPT_DES_MODE_CTR); break; case class_exists('Crypt_RC4'): $crypto = new Crypt_RC4(); break; default: extract(unpack('Nrandom', pack('H*', sha1(mt_rand(0, 0x7fffffff))))); return abs($random) % ($max - $min) + $min; } $crypto->setKey($key); $crypto->setIV($iv); $crypto->enableContinuousBuffer(); } extract(unpack('Nrandom', $crypto->encrypt(""))); return abs($random) % ($max - $min) + $min; }