C#加密转PHP解密

2021-12-20 00:00:00 encryption encryption-symmetric cookies php c#

我正在尝试在 C# 中加密一些(cookie)数据，然后在 PHP 中对其进行解密.我选择使用 Rijndael 加密.我几乎让它工作了，除了只有部分文本被解密！我从这个例子开始工作:在 C# 中解密 PHP 加密字符串

I'm trying to encrypt some (cookie) data in C# and then decrypt it in PHP. I have chosen to use Rijndael encryption. I've almost got it working, except only part of the text is decrypted! I started working from this example: Decrypt PHP encrypted string in C#

这是我正在加密的文本 (JSON)(已删除敏感信息):

Here's the text (JSON) that I am encrypting (sensitive information removed):

{"DisplayName":"xxx", "Username": "yyy", "EmailAddress":"zzz"}

所以我登录到 C# 应用程序，它从存储的密钥和 IV 创建/编码 cookie，然后重定向到应该解密/读取 cookie 的 PHP 应用程序.当我解密cookie时，它是这样的:<罢工>

So I login to the C# app which creates/encodes the cookie from stored Key and IV and then redirects to the PHP app which is supposed to decrypt/read the cookie. When I decrypt the cookie, it comes out like this: 

{"DisplayName":"xxx","F�A ;��HP=D�������4��z����ť���k�#E���R�j�5��t. t�D��"

更新:我已经更进一步了，这是现在的结果

UPDATE: i've gotten a little bit further and this is now the result

string(96) "{"DisplayName":"xxx","Username":"yyy","EmailAddress"�)ق��-�J��k/VV-v� �9�B`7^"

如您所见，它开始解密它，但随后变得一团糟......

As you can see, it starts decrypting it, but then gets messed up...

当解密字符串时，它是正确的(带填充，我有一个删除填充的功能)，但是如果我将测试字符串更改一个字符，我又得到了垃圾:

When Decrypt the string it comes out correct (with padding, which I have a function to remove padding), but if I change the test string by one character I get garbage again:

B�nHL�Ek    �¿?�UΣlO����OЏ�M��NO/�f.M���Lƾ�CC�Y>F��~�qd�+

这是我用来生成随机密钥和 IV 的 c# 代码:

更新:我现在只使用静态密钥/IV，它们是:

UPDATE: I'm just using static key/IV for now, here they are:

Key: lkirwf897+22#bbtrm8814z5qq=498j5
IV: 741952hheeyy66#cs!9hjv887mxx7@8y

<打击>

RijndaelManaged symmetricKey = new RijndaelManaged();
symmetricKey.BlockSize = 256;
symmetricKey.KeySize = 256;
symmetricKey.Padding = PaddingMode.Zeros;
symmetricKey.Mode = CipherMode.CBC;
string key = Convert.ToBase64String(symmetricKey.Key);
string IV = Convert.ToBase64String(symmetricKey.IV);

然后我将密钥和 IV 保存到数据库中，以便稍后检索以进行编码/解码.

I then save the key and IV to a database to be retrieved later for encoding/decoding.

这是完整的加密类:

public static class Encryption
    {
        public static string Encrypt(string prm_text_to_encrypt, string prm_key, string prm_iv)
        {
            var sToEncrypt = prm_text_to_encrypt;

            var rj = new RijndaelManaged()
            {
                Padding = PaddingMode.PKCS7,
                Mode = CipherMode.CBC,
                KeySize = 256,
                BlockSize = 256,
                //FeedbackSize = 256
            };

            var key = Encoding.ASCII.GetBytes(prm_key);
            var IV = Encoding.ASCII.GetBytes(prm_iv);
            //var key = Convert.FromBase64String(prm_key);
            //var IV = Convert.FromBase64String(prm_iv);

            var encryptor = rj.CreateEncryptor(key, IV);

            var msEncrypt = new MemoryStream();
            var csEncrypt = new CryptoStream(msEncrypt, encryptor, CryptoStreamMode.Write);

            var toEncrypt = Encoding.ASCII.GetBytes(sToEncrypt);

            csEncrypt.Write(toEncrypt, 0, toEncrypt.Length);
            csEncrypt.FlushFinalBlock();

            var encrypted = msEncrypt.ToArray();

            return (Convert.ToBase64String(encrypted));
        }

        public static string Decrypt(string prm_text_to_decrypt, string prm_key, string prm_iv)
        {

            var sEncryptedString = prm_text_to_decrypt;

            var rj = new RijndaelManaged()
            {
                Padding = PaddingMode.PKCS7,
                Mode = CipherMode.CBC,
                KeySize = 256,
                BlockSize = 256,
                //FeedbackSize = 256
            };

            var key = Encoding.ASCII.GetBytes(prm_key);
            var IV = Encoding.ASCII.GetBytes(prm_iv);
            //var key = Convert.FromBase64String(prm_key);
            //var IV = Convert.FromBase64String(prm_iv);

            var decryptor = rj.CreateDecryptor(key, IV);

            var sEncrypted = Convert.FromBase64String(sEncryptedString);

            var fromEncrypt = new byte[sEncrypted.Length];

            var msDecrypt = new MemoryStream(sEncrypted);
            var csDecrypt = new CryptoStream(msDecrypt, decryptor, CryptoStreamMode.Read);

            csDecrypt.Read(fromEncrypt, 0, fromEncrypt.Length);

            return (Encoding.ASCII.GetString(fromEncrypt));
        }

        public static void GenerateKeyIV(out string key, out string IV)
        {
            var rj = new RijndaelManaged()
            {
                Padding = PaddingMode.PKCS7,
                Mode = CipherMode.CBC,
                KeySize = 256,
                BlockSize = 256,
                //FeedbackSize = 256
            };
            rj.GenerateKey();
            rj.GenerateIV();

            key = Convert.ToBase64String(rj.Key);
            IV = Convert.ToBase64String(rj.IV);
        }
    }

这是我用来解密数据的 PHP 代码:

Here's the PHP code I am using to decrypt the data:

    function decryptRJ256($key,$iv,$string_to_decrypt)
{
    $string_to_decrypt = base64_decode($string_to_decrypt);
    $rtn = mcrypt_decrypt(MCRYPT_RIJNDAEL_256, $key, $string_to_decrypt, MCRYPT_MODE_CBC, $iv);
    //$rtn = rtrim($rtn, "4");
    $rtn = unpad($rtn);
    return($rtn);
}

function unpad($value)
{
    $blockSize = mcrypt_get_block_size(MCRYPT_RIJNDAEL_256, MCRYPT_MODE_CBC);
    //apply pkcs7 padding removal
    $packing = ord($value[strlen($value) - 1]);
    if($packing && $packing < $blockSize){
        for($P = strlen($value) - 1; $P >= strlen($value) - $packing; $P--){
            if(ord($value{$P}) != $packing){
                $packing = 0;
            }//end if
        }//end for
    }//end if 

    return substr($value, 0, strlen($value) - $packing); 
}

$ky = 'lkirwf897+22#bbtrm8814z5qq=498j5'; // 32 * 8 = 256 bit key
$iv = '741952hheeyy66#cs!9hjv887mxx7@8y'; // 32 * 8 = 256 bit iv

$enc = $_COOKIE["MyCookie"];

$dtext = decryptRJ256($ky, $iv, $enc);
var_dump($dtext);

我对这部分有点不确定，因为我看到的所有示例代码都只是将 base64 编码的字符串直接传递给解密器，但在我的示例中，我必须在传递之前对其进行 base64_decode否则我会得到密钥和 IV 长度不正确的错误.

更新:我正在使用 PHP 所需格式的 ASCII 键.如果我从 RijndaelManaged 类生成密钥，它们在 PHP 端不起作用，但我可以使用已知在 PHP 端工作的密钥，并在 RijndaelManaged C# 端使用它们.

UPDATE: I'm using ASCII keys in the format needed by PHP. If I generate keys from the RijndaelManaged class they dont work on the PHP side, but I can use keys that are known to work on PHP side and use them in the RijndaelManaged C# side.

如果我遗漏了任何相关信息，请告诉我.TIA！

Please let me know if I left out any pertinent information. TIA!

推荐答案

由于字符串部分正常，但最后有乱码，这表明加密中存在填充问题，该加密需要精确的 256 字节块.我建议在 C# 端将填充设置为 PKCS7 (PaddingMode.PKCS7) 而不是 Zeros，PHP 可以毫无问题地理解(因为它是该解析器的默认模式).

Since the string is partially OK, but there is gibberish at the end it would suggest a padding problem within the encryption which expects exact blocks of 256 bytes. I suggest setting the padding as PKCS7 (PaddingMode.PKCS7) instead of Zeros on the C# side which PHP will understand without issues (as it's the default mode on that parser).

糟糕，我没有注意到您的 PHP 中有以下内容:

Oops, I did not notice that you had the following in your PHP:

$enc = $_COOKIE["MyCookie"];

这是警告.PHP 可能无法按原样获取加密数据，并且正在运行一些 urldecode 清理.您应该打印此变量以查看它是否真正匹配从 C# 代码发送的内容.

This is the caveat. PHP is likely not getting the encrypted data as-is and is running some urldecode sanitizing. You should print this variable to see that it really matches what is being sent from the C# code.

编辑 2:

通过添加以下内容将空格转换为 cookie 中缺失的 + 字符:

Convert the whitespaces to missing + characters from the cookie by adding this:

str_replace(' ', '+', $enc);

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