随机生成token

转自：http://blog.csdn.net/jallin2001/article/details/5560053

    function genToken( $len = 32, $md5 = true ) {             # Seed random number generator                # Only needed for PHP versions prior to 4.2                mt_srand( (double)microtime()*1000000 );                # Array of characters, adjust as desired                $chars = array(                    'Q', '@', '8', 'y', '%', '^', '5', 'Z', '(', 'G', '_', 'O', '`',                    'S', '-', 'N', '<', 'D', '{', '}', '[', ']', 'h', ';', 'W', '.',                    '/', '|', ':', '1', 'E', 'L', '4', '&', '6', '7', '#', '9', 'a',                    'A', 'b', 'B', '~', 'C', 'd', '>', 'e', '2', 'f', 'P', 'g', ')',                    '?', 'H', 'i', 'X', 'U', 'J', 'k', 'r', 'l', '3', 't', 'M', 'n',                    '=', 'o', '+', 'p', 'F', 'q', '!', 'K', 'R', 's', 'c', 'm', 'T',                    'v', 'j', 'u', 'V', 'w', ',', 'x', 'I', '$', 'Y', 'z', '*'                );                # Array indice friendly number of chars;                $numChars = count($chars) - 1; $token = '';                # Create random token at the specified length                for ( $i=0; $i<$len; $i++ )                    $token .= $chars[ mt_rand(0, $numChars) ];                # Should token be run through md5?                if ( $md5 ) {                    # Number of 32 char chunks                    $chunks = ceil( strlen($token) / 32 ); $md5token = '';                    # Run each chunk through md5                    for ( $i=1; $i<=$chunks; $i++ )                        $md5token .= md5( substr($token, $i * 32 - 32, 32) );                    # Trim the token                    $token = substr($md5token, 0, $len);                } return $token;            }