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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:Decrypt PHP encrypted string in C#

这是我正在加密的文本(JSON)(删除了敏感信息):

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

所以我登录到 C# 应用程序,该应用程序从存储的密钥和 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,结果如下:

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

更新:我已经走得更远了,这就是现在的结果

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......

当解密字符串时它是正确的(带有填充,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,我会再次得到垃圾:

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:

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

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。

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:

    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, "\0\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,否则我会收到错误密钥和 IV 的长度不正确。

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 端工作的键并在 RijndaelManaged C# 端使用它们。

如果我遗漏了任何相关信息,请告诉我。蒂亚!

4

2 回答 2

19

为了后代,我将完整的解决方案放在这里。

C# 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,
        };

        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,
        };

        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,
        };
        rj.GenerateKey();
        rj.GenerateIV();

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

PHP解密片段

<?php
function decryptRJ256($key,$iv,$encrypted)
{
    //PHP strips "+" and replaces with " ", but we need "+" so add it back in...
    $encrypted = str_replace(' ', '+', $encrypted);

    //get all the bits
    $key = base64_decode($key);
    $iv = base64_decode($iv);
    $encrypted = base64_decode($encrypted);

    $rtn = mcrypt_decrypt(MCRYPT_RIJNDAEL_256, $key, $encrypted, MCRYPT_MODE_CBC, $iv);
    $rtn = unpad($rtn);
    return($rtn);
}

//removes PKCS7 padding
function unpad($value)
{
    $blockSize = mcrypt_get_block_size(MCRYPT_RIJNDAEL_256, MCRYPT_MODE_CBC);
    $packing = ord($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;
            }
        }
    }

    return substr($value, 0, strlen($value) - $packing); 
}
?>
<pre>
<?php

$enc = $_COOKIE["MyCookie"];

$ky = ""; //INSERT THE KEY GENERATED BY THE C# CLASS HERE
$iv = ""; //INSERT THE IV GENERATED BY THE C# CLASS HERE

$json_user = json_decode(decryptRJ256($ky, $iv, $enc), true);

var_dump($json_user);

?>
于 2012-08-10T21:38:33.470 回答
5

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,需要精确的 256 字节块。我建议将填充设置为PKCS7 (PaddingMode.PKCS7) 而不是 C# 端的Zeros,PHP 可以毫无问题地理解(因为它是该解析器的默认模式)。

编辑:糟糕,我没有注意到您的 PHP 中有以下内容:

$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。

编辑2:

通过添加以下内容,将 cookie 中的空格转换为缺少的 + 字符:

str_replace(' ', '+', $enc);
于 2012-08-10T19:35:53.123 回答