Question

所以这是我的烂摊子。它返回随机Unicode字符。我让它使用相同的密钥用于两种方法，以及相同的IV，并且我对它们使用相同的编码。是什么导致随机响应？

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

namespace FileFish
{
    class Program
    {
        public static void Main()
        {
            AesCryptoServiceProvider aes = new AesCryptoServiceProvider();
            aes.GenerateIV();
            Console.WriteLine(Decrypt(Encoding.UTF8.GetBytes("APPLEAPPLEAPPLEAPPLEAPPLEAPPLEAP"), aes.IV, Encrypt(Encoding.UTF8.GetBytes("APPLEAPPLEAPPLEAPPLEAPPLEAPPLEAP"), aes.IV, "cheese")));
            Console.ReadKey(true);
        }

        private static byte[] Encrypt(byte[] key, byte[] iv, string plaintext)
        {
            AesCryptoServiceProvider aes = new AesCryptoServiceProvider();
            aes.Key = key;
            aes.IV = iv;
            ICryptoTransform encryptor = aes.CreateEncryptor();
            MemoryStream ms = new MemoryStream();
            StreamWriter sw = new StreamWriter(new CryptoStream(ms, encryptor, CryptoStreamMode.Write));
            sw.Write(plaintext);
            return ms.ToArray();
        }

        private static string Decrypt(byte[] key, byte[] iv, byte[] ciphertext)
        {
            AesCryptoServiceProvider aes = new AesCryptoServiceProvider();
            aes.Key = key;
            aes.IV = iv;
            ICryptoTransform decryptor = aes.CreateEncryptor();
            MemoryStream ms = new MemoryStream(ciphertext);
            StreamReader sr = new StreamReader(new CryptoStream(ms, decryptor, CryptoStreamMode.Read));
            return sr.ReadToEnd();
        }
    }
}

Answer 1

您的代码示例失败，因为Encrypt方法返回一个空数组。而不是试图自己动手，你最好不要使用被证明有用的东西。

AesCryptoServiceProvider documentation中的示例代替示例代码中的Encrypt和Decrypt方法：

static byte[] EncryptStringToBytes_Aes(string plainText, byte[] Key, byte[] IV)
{
    // Check arguments.
    if (plainText == null || plainText.Length <= 0)
        throw new ArgumentNullException("plainText");
    if (Key == null || Key.Length <= 0)
        throw new ArgumentNullException("Key");
    if (IV == null || IV.Length <= 0)
        throw new ArgumentNullException("Key");
    byte[] encrypted;
    // Create an AesCryptoServiceProvider object
    // with the specified key and IV.
    using (AesCryptoServiceProvider aesAlg = new AesCryptoServiceProvider())
    {
        aesAlg.Key = Key;
        aesAlg.IV = IV;

        // Create a decrytor to perform the stream transform.
        ICryptoTransform encryptor = aesAlg.CreateEncryptor(aesAlg.Key, aesAlg.IV);

        // Create the streams used for encryption.
        using (MemoryStream msEncrypt = new MemoryStream())
        {
            using (CryptoStream csEncrypt = new CryptoStream(msEncrypt, encryptor, CryptoStreamMode.Write))
            {
                using (StreamWriter swEncrypt = new StreamWriter(csEncrypt))
                {
                    //Write all data to the stream.
                    swEncrypt.Write(plainText);
                }
                encrypted = msEncrypt.ToArray();
            }
        }
    }

    // Return the encrypted bytes from the memory stream.
    return encrypted;
}

static string DecryptStringFromBytes_Aes(byte[] cipherText, byte[] Key, byte[] IV)
{
    // Check arguments.
    if (cipherText == null || cipherText.Length <= 0)
        throw new ArgumentNullException("cipherText");
    if (Key == null || Key.Length <= 0)
        throw new ArgumentNullException("Key");
    if (IV == null || IV.Length <= 0)
        throw new ArgumentNullException("Key");

    // Declare the string used to hold
    // the decrypted text.
    string plaintext = null;

    // Create an AesCryptoServiceProvider object
    // with the specified key and IV.
    using (AesCryptoServiceProvider aesAlg = new AesCryptoServiceProvider())
    {
        aesAlg.Key = Key;
        aesAlg.IV = IV;

        // Create a decrytor to perform the stream transform.
        ICryptoTransform decryptor = aesAlg.CreateDecryptor(aesAlg.Key, aesAlg.IV);

        // Create the streams used for decryption.
        using (MemoryStream msDecrypt = new MemoryStream(cipherText))
        {
            using (CryptoStream csDecrypt = new CryptoStream(msDecrypt, decryptor, CryptoStreamMode.Read))
            {
                using (StreamReader srDecrypt = new StreamReader(csDecrypt))
                {

                    // Read the decrypted bytes from the decrypting stream
                    // and place them in a string.
                    plaintext = srDecrypt.ReadToEnd();
                }
            }
        }
    }

    return plaintext;
}

Answer 2

此外，并不是造成这个问题的原因，而是： http://blogs.msdn.com/b/shawnfa/archive/2005/11/10/491431.aspx

不要通过字符串编码往返传输密文

AES往返产生随机字符

2 个答案: