c# - 在不同的运行期间解密加密的字符串

问题描述

下面的代码工作正常并加密：

hello world

至：

BgGUY2eR7GfumjbQr58tBQ==

跑步。下次这可能会有所不同，例如：

CYIM7V/h3iXu5PYzwmQ33g==

我认为这是这个算法的重点。如何解密不久前加密的字符串？

如果我做：

static void Main(string[] args)
{
    var key = @"abcdefghijklmnopqrstuvw==";

    using (var aesAlg = Aes.Create())
    {
    aesAlg.Mode = CipherMode.CBC;
    aesAlg.Padding = PaddingMode.PKCS7;
    aesAlg.Key = Convert.FromBase64String(key);
    aesAlg.GenerateIV();

    var decryptor = aesAlg.CreateDecryptor(aesAlg.Key, aesAlg.IV);
    var helloWorld = DecryptProperty(decryptor, "CYIM7V/h3iXu5PYzwmQ33g==");
    }

}

我得到：

System.Security.Cryptography.CryptographicException
  HResult=0x80131430
  Message=Padding is invalid and cannot be removed.
  Source=System.Core
  StackTrace:
   at System.Security.Cryptography.CapiSymmetricAlgorithm.DepadBlock(Byte[] block, Int32 offset, Int32 count)
   at System.Security.Cryptography.CapiSymmetricAlgorithm.TransformFinalBlock(Byte[] inputBuffer, Int32 inputOffset, Int32 inputCount)
   at System.Security.Cryptography.CryptoStream.Read(Byte[] buffer, Int32 offset, Int32 count)
   at System.IO.StreamReader.ReadBuffer()
   at System.IO.StreamReader.ReadToEnd()
   at crypt.Program.DecryptProperty(ICryptoTransform decryptor, String valueToDecrypt)

有任何想法吗？如何解密过去使用密钥加密的字符串？谢谢！

工作代码：

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

namespace crypt
{
    class Program
    {
        static void Main(string[] args)
        {
            var key = @"abcdefghijklmnopqrstuvw==";

            using (var aesAlg = Aes.Create())
            {
                aesAlg.Mode = CipherMode.CBC;
                aesAlg.Padding = PaddingMode.PKCS7;
                aesAlg.Key = Convert.FromBase64String(key);
                aesAlg.GenerateIV();

                var encryptor = aesAlg.CreateEncryptor(aesAlg.Key, aesAlg.IV);
                var encHelloWorld = EncryptProperty(encryptor, "hello world");

                var decryptor = aesAlg.CreateDecryptor(aesAlg.Key, aesAlg.IV);
                var helloWorld = DecryptProperty(decryptor, encHelloWorld);
            }

        }
        private static string EncryptProperty(ICryptoTransform encryptor, string valueToEncrypt)
        {
            byte[] encrypted;
            using (var msEncrypt = new MemoryStream())
            {
                using (var csEncrypt = new CryptoStream(msEncrypt, encryptor, CryptoStreamMode.Write))
                {
                    using (var swEncrypt = new StreamWriter(csEncrypt))
                    {
                        swEncrypt.Write(valueToEncrypt);
                    }
                    encrypted = msEncrypt.ToArray();
                }
            }
            return Convert.ToBase64String(encrypted);
        }

        private static string DecryptProperty(ICryptoTransform decryptor, string valueToDecrypt)
        {
            string decrypted;

            using (var msDecrypt = new MemoryStream(Convert.FromBase64String(valueToDecrypt)))
            {
                using (var csDecrypt = new CryptoStream(msDecrypt, decryptor, CryptoStreamMode.Read))
                {
                    using (var srDecrypt = new StreamReader(csDecrypt))
                    {
                        decrypted = srDecrypt.ReadToEnd();
                    }
                }
            }
            return decrypted;
        }
    }
}

标签： c#encryption

c# - 在不同的运行期间解密加密的字符串

问题描述

解决方案

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