PHP进行3des加密

<?php

$str = '123456';

    $key = "Njqm8hxfGMWCPRo2VndmHCoP";
    $cipher = MCRYPT_TRIPLEDES;
    $mode = MCRYPT_MODE_CBC;
$data=utf8_encode($str);
    $iv = mcrypt_create_iv(mcrypt_get_iv_size($cipher,$mode),MCRYPT_RAND);
//$iv="5P5CoL4r";
    echo "原文：".utf8_encode($str)."<br>";
    $str_encrypt = mcrypt_encrypt($cipher,$key,$data,$mode,$iv);
    echo "加密后的内容是：".base64_encode($str_encrypt)."<br>";
 
    $str_decrypt = mcrypt_decrypt($cipher,$key,$str_encrypt,$mode,$iv);

    echo "解密后的内容：".$str_decrypt."<br>";

?>