如何解密PHP中的md5字符串 [英] How to decrypt an md5 string in PHP

问题描述

我已经用 md5（）编码了一个字符串，我想要解密相同的字符串。

I have encoded a string with md5() and I want to decrypt the same string.

我写了以下代码：

<?php 

$rr = md5(utf8_encode('hello'));
echo $rr;

$rr1 = md5(utf8_decode('5d41402abc4b2a76b9719d911017c592'));
echo '<br/>' .$rr1;
?>

现在我可以加密字符串。但现在，我想解密字符串。我试过：

Now I am able to encrypt the string. But now, I want to decrypt the string. I have tried:

md5(utf_decode('string'));

但它不工作。如何解密使用 md5（）加密的字符串？

But it is not working. How can I decrypt the string which is encrypted with md5()?

推荐答案

你不能！ MD5是单向散列，不加密。总之，应该是不可能扭转的。你使用它是例如存储密码。你不需要知道密码是什么;您只需要输入密码字段中的 md5（），并查看它是否与存储的 md5（）用户密码的值。

You can't! MD5 is a one-way hash, not encryption. The whole point is that it's supposed to be impossible to reverse. What you'd use it for is, for example, storing a password. You don't need to know what the password is; you just need to md5() whatever the user typed into the password field, and see if it matches the stored md5() value of the user's password.

如果您想要加密和解密，请查看 AES / Twofish / Blowfish。 MCrypt模块将有助于您。

If you want to be able to encrypt and decrypt, look into something like AES / Twofish / Blowfish. The MCrypt module will help you quite a bit.

这个问题为PHP中加密和解密提供了一些额外的资源。

This question provides some additional resources for how to encrypt and decrypt in PHP.

我还应该指出， md5（）是一个弱的，容易出错的哈希算法，不应该被高安全性应用信任。我最少使用sha256，或sha512。

I should also point out that md5() is a weak, collision-prone hashing algorithm, and shouldn't be trusted for high-security applications. I would use sha256 at minimum, or sha512.

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