ruby.rb

function encode_password($plain, $challenge, $secret) {
    if ((strlen($challenge) % 2) != 0 ||
        strlen($challenge) == 0)
        return FALSE;

    $hexchall = hex2bin($challenge);
    if ($hexchall === FALSE)
        return FALSE;

    if (strlen($secret) > 0) {
        $crypt_secret = md5($hexchall . $secret, TRUE);
        $len_secret = 16;
    } else {
        $crypt_secret = $hexchall;
        $len_secret = strlen($hexchall);
    }

    /* simulate C style \0 terminated string */
    $plain .= "\x00";
    $crypted = '';
    for ($i = 0; $i < strlen($plain); $i++)
        $crypted .= $plain[$i] ^ $crypt_secret[$i % $len_secret];

    $extra_bytes = 0;//rand(0, 16);
    for ($i = 0; $i < $extra_bytes; $i++)
        $crypted .= chr(rand(0, 255));

    return bin2hex($crypted);
}