用PHP重写Rijndael 256 C#加密代码

Question

我有一个用C#编写的加密/解密算法 - 我需要能够在PHP中生成相同的加密,这样我就可以通过HTTP发送加密文本,在C#端解密.这是加密的C#代码.

this.m_plainText = string.Empty;
this.m_passPhrase = "passpharse";
this.m_saltValue = "saltvalue";
this.m_hashAlgorithm = "SHA1";
this.m_passwordIterations = 2;
this.m_initVector = "1a2b3c4d5e6f7g8h";
this.m_keySize = 256;

public string Encrypt()
{
    string plainText = this.m_plainText;
    string passPhrase = this.m_passPhrase;
    string saltValue = this.m_saltValue;
    string hashAlgorithm = this.m_hashAlgorithm;
    int passwordIterations = this.m_passwordIterations;
    string initVector = this.m_initVector;
    int keySize = this.m_keySize;

    // Convert strings into byte arrays.
    // Let us assume that strings only contain ASCII codes.
    // If strings include Unicode characters, use Unicode, UTF7, or UTF8 
    // encoding.
    byte[] initVectorBytes = Encoding.ASCII.GetBytes(initVector);
    byte[] saltValueBytes = Encoding.ASCII.GetBytes(saltValue);

    // Convert our plaintext into a byte array.
    // Let us assume that plaintext contains UTF8-encoded characters.
    byte[] plainTextBytes = Encoding.UTF8.GetBytes(plainText);

    // First, we must create a password, from which the key will be derived.
    // This password will be generated from the specified passphrase and 
    // salt value. The password will be created using the specified hash 
    // algorithm. Password creation can be done in several iterations.
    PasswordDeriveBytes password = new PasswordDeriveBytes(
                                                    passPhrase,
                                                    saltValueBytes,
                                                    hashAlgorithm,
                                                    passwordIterations);

    // Use the password to generate pseudo-random bytes for the encryption
    // key. Specify the size of the key in bytes (instead of bits).
    byte[] keyBytes = password.GetBytes(keySize / 8);

    // Create uninitialized Rijndael encryption object.
    RijndaelManaged symmetricKey = new RijndaelManaged();

    // It is reasonable to set encryption mode to Cipher Block Chaining
    // (CBC). Use default options for other symmetric key parameters.
    symmetricKey.Mode = CipherMode.CBC;

    // Generate encryptor from the existing key bytes and initialization 
    // vector. Key size will be defined based on the number of the key 
    // bytes.
    ICryptoTransform encryptor = symmetricKey.CreateEncryptor(
                                                     keyBytes,
                                                     initVectorBytes);

    // Define memory stream which will be used to hold encrypted data.
    MemoryStream memoryStream = new MemoryStream();

    // Define cryptographic stream (always use Write mode for encryption).
    CryptoStream cryptoStream = new CryptoStream(memoryStream,
                                                 encryptor,
                                                 CryptoStreamMode.Write);
    // Start encrypting.
    cryptoStream.Write(plainTextBytes, 0, plainTextBytes.Length);

    // Finish encrypting.
    cryptoStream.FlushFinalBlock();

    // Convert our encrypted data from a memory stream into a byte array.
    byte[] cipherTextBytes = memoryStream.ToArray();

    // Close both streams.
    memoryStream.Close();
    cryptoStream.Close();

    // Convert encrypted data into a base64-encoded string.
    string cipherText = Convert.ToBase64String(cipherTextBytes);

    // Return encrypted string.
    return cipherText;
}

我有一些类似的PHP代码可能有所帮助.它没有完全按照需要做,但我认为这可能是一个好的开始.

<?php

/*
 * DEFINE CONSTANTS
 */
$HashPassPhrase = "passpharse";
$HashSalt = "saltvalue";
$HashAlgorithm = "SHA1";
$HashIterations = "2";
$InitVector = "1a2b3c4d5e6f7g8h";        // Must be 16 bytes
$keySize = "256";

class Cipher {
    private $securekey, $iv;
    function __construct($textkey) {
        $this->securekey = hash($HashAlgorithm,$textkey,TRUE);
        $this->iv = $InitVector;
    }
    function encrypt($input) {
        return base64_encode(mcrypt_encrypt(MCRYPT_RIJNDAEL_256, $this->securekey, $input, MCRYPT_MODE_CBC, $this->iv));
    }
    function decrypt($input) {
        return trim(mcrypt_decrypt(MCRYPT_RIJNDAEL_256, $this->securekey, base64_decode($input), MCRYPT_MODE_CBC, $this->iv));
    }
}

$cipher = new Cipher($HashPassPhrase);

$encryptedtext = $cipher->encrypt("Text To Encrypt");
echo "->encrypt = $encryptedtext<br />";

$decryptedtext = $cipher->decrypt($encryptedtext);
echo "->decrypt = $decryptedtext<br />";

var_dump($cipher);

？>

Answer 1

您需要获得来自口令方式与C#代码相同确实在关键PasswordDeriveBytes.据记录,这可以根据RFC2898进行PBKDF1密钥派生:

此类使用PKCS#5 v2.0标准中定义的PBKDF1算法的扩展来派生适合用作密码的密钥材料的字节.该标准记录在IETF RRC 2898中.

有一些PHP库可以实现PBKDF1,但是基于RFC可以很容易地从头开始编写:

PBKDF1(P,S,c,dkLen)

选项:哈希
底层哈希函数

输入:P
密码,八位字节串S盐,八位八位字符串c迭代计数,正整数dkLen预期长度,以导出密钥的八位字节为单位,正整数,最多16为MD2或MD5,20为SHA-1

输出:DK派生密钥,dkLen-octet字符串

脚步:

  1. If dkLen > 16 for MD2 and MD5, or dkLen > 20 for SHA-1, output
     "derived key too long" and stop.

  2. Apply the underlying hash function Hash for c iterations to the
     concatenation of the password P and the salt S, then extract
     the first dkLen octets to produce a derived key DK:

               T_1 = Hash (P || S) ,
               T_2 = Hash (T_1) ,
               ...
               T_c = Hash (T_{c-1}) ,
               DK = Tc<0..dkLen-1>

  3. Output the derived key DK.

更新

当您在这种情况下发现自己时,通常会搜索一个示例实现,以显示每一步的值.例如http://www.di-mgt.com.au/cryptoKDFs.html#examplespbkdf上的那个:

Password = "password" 
         = (0x)70617373776F7264
Salt     = (0x)78578E5A5D63CB06
Count    = 1000
kLen     = 16
Key      = PBKDF1(Password, Salt, Count, kLen)
         = (0x)DC19847E05C64D2FAF10EBFB4A3D2A20

P || S = 70617373776F726478578E5A5D63CB06
T_1=     D1F94C4D447039B034494400F2E7DF9DCB67C308
T_2=     2BB479C1D369EA74BB976BBA2629744E8259C6F5
...
T_999=   6663F4611D61571068B5DA168974C6FF2C9775AC
T_1000=  DC19847E05C64D2FAF10EBFB4A3D2A20B4E35EFE
Key=     DC19847E05C64D2FAF10EBFB4A3D2A20

所以现在让我们编写一个执行此操作的PHP函数:

function PBKDF1($pass,$salt,$count,$dklen) { 
    $t = $pass.$salt;
    //echo 'S||P: '.bin2hex($t).'<br/>';
    $t = sha1($t, true); 
    //echo 'T1:' . bin2hex($t) . '<br/>';
    for($i=2; $i <= $count; $i++) { 
        $t = sha1($t, true); 
        //echo 'T'.$i.':' . bin2hex($t) . '<br/>';
    } 
    $t = substr($t,0,$dklen); 
    return $t;      
}

现在你可以看到你的方式的错误:你没有指定所有重要的raw=true参数sha1.让我们看看我们的功能输出是什么:

$HashPassPhrase = pack("H*","70617373776F7264");
$HashSalt = pack("H*","78578E5A5D63CB06"); 
$HashIterations = 1000; 
$devkeylength = 16; 
$devkey = PBKDF1($HashPassPhrase,$HashSalt,$HashIterations,$devkeylength);
echo 'Key:' . bin2hex(substr($devkey, 0, 8)) . '<br/>';
echo 'IV:' . bin2hex(substr($devkey, 8, 8)) .'<br/>';
echo 'Expected: DC19847E05C64D2FAF10EBFB4A3D2A20<br/>';

这个输出恰好是预期的结果:

Key:dc19847e05c64d2f
IV:af10ebfb4a3d2a20
Expected: DC19847E05C64D2FAF10EBFB4A3D2A20

接下来,我们可以验证C#函数是否执行相同的操作:

            byte[] password = Encoding.ASCII.GetBytes("password");
            byte[] salt = new byte[] { 0x78, 0x57, 0x8e, 0x5a, 0x5d, 0x63, 0xcb, 0x06};

            PasswordDeriveBytes pdb = new PasswordDeriveBytes(
                password, salt, "SHA1", 1000);

            byte[] key = pdb.GetBytes(8);
            byte[] iv = pdb.GetBytes(8);

            Console.Out.Write("Key: ");
            foreach (byte b in key)
            {
                Console.Out.Write("{0:x} ", b);
            }
            Console.Out.WriteLine();

            Console.Out.Write("IV: ");
            foreach (byte b in iv)
            {
                Console.Out.Write("{0:x} ", b);
            }
            Console.Out.WriteLine();

这会产生相同的输出:

Key: dc 19 84 7e 5 c6 4d 2f
IV: af 10 eb fb 4a 3d 2a 20

QED

奖金解释

请不要做加密,如果你不知道究竟你在做什么.即使你的PHP实现正确,你发布的C#代码也有一些严重的问题.你正在使用代表十六进制转储的stirng混合字节数组,你使用硬编码的IV而不是从密码和盐中导出它,这只是整体上的错误.请使用现成的加密方案,如SSL或S-MIME,不要重新创建自己的加密方案.你会弄错的.