Question

我是C＃的新手，我真的需要帮助。我需要在C＃中用AES-256-CBC加密/解密一个字符串，我发现这个加密一个字符串：

    public static string EncryptString(string message, string KeyString, string IVString)
    {
        byte[] Key = ASCIIEncoding.UTF8.GetBytes(KeyString);
        byte[] IV = ASCIIEncoding.UTF8.GetBytes(IVString);

        string encrypted = null;
        RijndaelManaged rj = new RijndaelManaged();
        rj.Key = Key;
        rj.IV = IV;
        rj.Mode = CipherMode.CBC;

        try
        {
            MemoryStream ms = new MemoryStream();

            using (CryptoStream cs = new CryptoStream(ms, rj.CreateEncryptor(Key, IV), CryptoStreamMode.Write))
            {
                using (StreamWriter sw = new StreamWriter(cs))
                {
                    sw.Write(message);
                    sw.Close();
                }
                cs.Close();
            }
            byte[] encoded = ms.ToArray();
            encrypted = Convert.ToBase64String(encoded);

            ms.Close();
        }
        catch (CryptographicException e)
        {
            Console.WriteLine("A Cryptographic error occurred: {0}", e.Message);
            return null;
        }
        catch (UnauthorizedAccessException e)
        {
            Console.WriteLine("A file error occurred: {0}", e.Message);
            return null;
        }
        catch (Exception e)
        {
            Console.WriteLine("An error occurred: {0}", e.Message);
        }
        finally
        {
            rj.Clear();
        }
        return encrypted;
    }

我尝试根据上面的代码编写一个解密函数，下面的代码是我做的：

  // Decrypt a byte array into a byte array using a key and an IV 
        private byte[] Decrypt(byte[] cipherData, byte[] Key, byte[] IV)
        {
            byte[] decryptedData;
            //string plaintext = null;
            //MemoryStream ms = new MemoryStream(cipherData);

            RijndaelManaged alg = new RijndaelManaged();
   alg.KeySize = 256;
            alg.BlockSize = 128;
            alg.Key = Key;
            alg.IV = IV;
            alg.Mode = CipherMode.CBC;
            alg.Padding = PaddingMode.Zeros;

            //Array.Copy(Key, 0, IV, 0, IV.Length);

            ICryptoTransform decryptor = alg.CreateDecryptor(alg.Key, alg.IV);

            using(MemoryStream ms = new MemoryStream(cipherData))
            {
                using (CryptoStream csDecrypt = new CryptoStream(ms, decryptor, CryptoStreamMode.Read))
                {
                    using (StreamReader sw = new StreamReader(csDecrypt))
                    {
                        sw.ReadToEnd();
                        sw.Close();
                    }

                    csDecrypt.Close();
                    decryptedData = ms.ToArray();
                }
            }

            //byte[] decryptedData = System.Text.Encoding.Unicode.GetBytes(plaintext);
            return decryptedData; 
        }

但这是无稽之谈，它无法解密任何东西。我真的很困惑，需要帮助。谢谢你的帮助！

P / s：请不要给我其他类似的回答问题，我已经看过了。它们的加密功能与上述加密功能不具有相同的输出，而我需要解密必须由上述功能加密的字符串。我有两个用PHP编写解密函数的朋友和Objective-C，它与上面的加密函数相匹配，让他们再做一次是不好的。

Answer 1

查看加密，这样的事情应该这样做，从加密中传递结果字符串应该返回原始字符串;

// Decrypt a string into a string using a key and an IV 
public static string Decrypt(string cipherData, string keyString, string ivString)
{
    byte[] key = Encoding.UTF8.GetBytes(keyString);
    byte[] iv  = Encoding.UTF8.GetBytes(ivString);

    try
    {
        using (var rijndaelManaged =
               new RijndaelManaged {Key = key, IV = iv, Mode = CipherMode.CBC})
        using (var memoryStream = 
               new MemoryStream(Convert.FromBase64String(cipherData)))
        using (var cryptoStream =
               new CryptoStream(memoryStream,
                   rijndaelManaged.CreateDecryptor(key, iv),
                   CryptoStreamMode.Read))
        {
            return new StreamReader(cryptoStream).ReadToEnd();
        }
    }
    catch (CryptographicException e)
    {
        Console.WriteLine("A Cryptographic error occurred: {0}", e.Message);
        return null;
    }
    // You may want to catch more exceptions here...
}

小记;如果您使用密钥字符串中的UTF8编码获取密钥，UTF8编码可能会为国际字符提供多个字节，这可能会给密钥或IV加密/解密的长度错误。此外，使用8个字符和可打印字符的小范围密码/密钥不会给你非常安全的加密，你可能想要在使用它作为密钥之前运行字符串SHA1或类似的字符串（这可能会使它与它不兼容）当前加密）

如何解密AES-256-CBC加密字符串

1 个答案: