Question

我正在与客户进行数据交换集成，他们发送给我的数据使用他们的C＃encrypt方法加密（如下）。

我的应用程序正在运行PHP 5.3，我需要一个等效的代码来解密他们发送的数据。我有PHP代码，但它没有正确解密客户端数据。

显然，我在加密/解密方法，IV键或其他方面犯了一些错误。谁能发现错误？

感谢。

C＃代码（来自我的客户）：

using System;
using System.Security.Cryptography;
using System.Text;
using System.IO;

public class Program
{
    public static void Main()
    {
        var text = "this is a plain string";
        var enc = Program.Encrypt(text);
        Console.WriteLine(enc);
        Console.WriteLine(Program.Decrypt(enc));
    }

    public static string Encrypt(string clearText)
    {
        var EncryptionKey = "1234567890123456";
        byte[] clearBytes = Encoding.Unicode.GetBytes(clearText);
        using (Aes encryptor = Aes.Create())
        {
            byte[] IV = new byte[15];
            var rand = new Random();
            rand.NextBytes(IV);
            Rfc2898DeriveBytes pdb = new Rfc2898DeriveBytes(EncryptionKey, IV);
            encryptor.Key = pdb.GetBytes(32);
            encryptor.IV = pdb.GetBytes(16);
            using (MemoryStream ms = new MemoryStream())
            {
                using (CryptoStream cs = new CryptoStream(ms, encryptor.CreateEncryptor(), CryptoStreamMode.Write))
                {
                    cs.Write(clearBytes, 0, clearBytes.Length);
                    cs.Close();
                }

                clearText = Convert.ToBase64String(IV) + Convert.ToBase64String(ms.ToArray());
            }
        }

        return clearText;
    }

    public static string Decrypt(string cipherText)
    {
        var EncryptionKey = "1234567890123456";
        byte[] IV = Convert.FromBase64String(cipherText.Substring(0, 20));
        cipherText = cipherText.Substring(20).Replace(" ", "+");
        byte[] cipherBytes = Convert.FromBase64String(cipherText);
        using (Aes encryptor = Aes.Create())
        {
            Rfc2898DeriveBytes pdb = new Rfc2898DeriveBytes(EncryptionKey, IV);
            encryptor.Key = pdb.GetBytes(32);
            encryptor.IV = pdb.GetBytes(16);
            using (MemoryStream ms = new MemoryStream())
            {
                using (CryptoStream cs = new CryptoStream(ms, encryptor.CreateDecryptor(), CryptoStreamMode.Write))
                {
                    cs.Write(cipherBytes, 0, cipherBytes.Length);
                    cs.Close();
                }

                cipherText = Encoding.Unicode.GetString(ms.ToArray());
            }
        }

        return cipherText;
    }
}

PHP代码我有：

public function encrypt($plainText)
{
    $secretKey = '1234567890123456';

    return rtrim(
        base64_encode(
            mcrypt_encrypt(
                MCRYPT_RIJNDAEL_256,
                $secretKey, $plainText,
                MCRYPT_MODE_ECB,
                mcrypt_create_iv(
                    mcrypt_get_iv_size(
                        MCRYPT_RIJNDAEL_256,
                        MCRYPT_MODE_ECB
                    ),
                    MCRYPT_RAND)
            )
        ), "\0"
    );
}

public function decrypt($encodedData)
{
    $secretKey = '1234567890123456';

    return rtrim(
        mcrypt_decrypt(
            MCRYPT_RIJNDAEL_256,
            $secretKey,
            base64_decode($encodedData),
            MCRYPT_MODE_ECB,
            mcrypt_create_iv(
                mcrypt_get_iv_size(
                    MCRYPT_RIJNDAEL_256,
                    MCRYPT_MODE_ECB
                ),
                MCRYPT_RAND
            )
        ), "\0"
    );
}

Answer 1

有人能发现错误吗？

是的，最重要的不是你的错：mcrypt's confusing API strikes again。

尽管如此，这里确实存在多处错误。

return rtrim( // unnecessary
    base64_encode(
        mcrypt_encrypt(
            MCRYPT_RIJNDAEL_256, // Not AES
            $secretKey, $plainText,
            MCRYPT_MODE_ECB, // BAD, use MCRYPT_MODE_CBC or 'ctr' instead
            mcrypt_create_iv(
                mcrypt_get_iv_size(      // unless you're going make this
                    MCRYPT_RIJNDAEL_256, // configurable, you should just
                    MCRYPT_MODE_ECB      // hard-code this as an integer
                ),
                MCRYPT_RAND) // BAD, use MCRYPT_DEV_URANDOM
        )
    ), "\0"
);

如果您要生成IV，则应进行通信，以便您的收件人可以成功解密相同的第一个块。 C＃代码执行此操作，而PHP则不这样做。

从加密工程的角度来看，您应该考虑在C＃land和PHP中部署Encrypt然后Authenticate协议。见this blog post on encryption and authentication。另外，all the crypto code you've ever written is probably broken。

Answer 2

似乎PHP脚本使用了错误的模式：
https://msdn.microsoft.com/en-us/library/system.security.cryptography.symmetricalgorithm.mode%28v=vs.110%29.aspx
C＃功能不设置任何模式，因此默认为CBC PHP部分使用的是ECB，这不仅错误，而且不安全。

PHP相当于.net AES加密

2 个答案: