Question

我会尽量保持这个简短。

请保持良好，我一般不会写C＃，最初写这个类的开发人员也不会。

无论如何简单的概念，用字符串和密钥调用EncryptString静态方法。然后使用加密的字符串和密钥调用DecryptString（与之前相同）。

这用于输出保存在文件系统上的文件，然后获取内容（通过另一个类）。

我遇到的问题是加密工作得非常好，但在解密时，我得到一个关于密钥的例外。在另一位开发人员也搔了几个小时之后，现在已经在我的头上刮了几个小时。

负责类：

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

namespace MySoftwarePackage.Pakages
{
    public class Encrypt
    {

        public static string DecryptString(string cipherText, string encryptionKey)
        {

            Console.WriteLine("ENCRYPTION KEY: " + encryptionKey);

            var fullCipher = Convert.FromBase64String(cipherText);

            var iv = new byte[16];
            var cipher = new byte[32];

            Buffer.BlockCopy(fullCipher, 0, iv, 0, iv.Length);
            Buffer.BlockCopy(fullCipher, iv.Length, cipher, 0, iv.Length);
            var key = Encoding.UTF8.GetBytes(encryptionKey);

            Console.WriteLine("ENCODED: " + key);

            using (var aesAlg = Aes.Create())
            {
                using (var decryptor = aesAlg.CreateDecryptor(key, iv))
                {
                    string result;
                    using (var msDecrypt = new MemoryStream(cipher))
                    {
                        using (var csDecrypt = new CryptoStream(msDecrypt, decryptor, CryptoStreamMode.Read))
                        {
                            using (var srDecrypt = new StreamReader(csDecrypt))
                            {
                                result = srDecrypt.ReadToEnd();
                            }
                        }
                    }

                    return result;
                }
            }
        }
    }
}

例外：

fail: Microsoft.AspNetCore.Server.Kestrel[13]
      Connection id "0HL83721K735O": An unhandled exception was thrown by the application.
System.Security.Cryptography.CryptographicException: Specified padding mode is not valid for this algorithm.
   at Internal.Cryptography.UniversalCryptoDecryptor.DepadBlock(Byte[] block, Int32 offset, Int32 count)
   at Internal.Cryptography.UniversalCryptoDecryptor.UncheckedTransformFinalBlock(Byte[] inputBuffer, Int32 inputOffset, Int32 inputCount)
   at Internal.Cryptography.UniversalCryptoTransform.TransformFinalBlock(Byte[] inputBuffer, Int32 inputOffset, Int32 inputCount)
   at System.Security.Cryptography.CryptoStream.FlushFinalBlock()
   at System.Security.Cryptography.CryptoStream.Dispose(Boolean disposing)
   at System.IO.Stream.Close()
   at System.IO.StreamReader.Dispose(Boolean disposing)
   at System.IO.TextReader.Dispose()
   at MySoftwarePackage.Pakages.Encrypt.DecryptString(String cipherText, String encryptionKey) in /Users/matt/SoftwarePackage-desktop/src/api/Pakages/Encrypt.cs:line 39
   at MySoftwarePackage.Pakages.DataRetriever.UnencryptData() in /Users/matt/SoftwarePackage-desktop/src/api/Pakages/DataRetriever.cs:line 39
   at MySoftwarePackage.Pakages.DataRetriever..ctor(String entityType, String entityId) in /Users/matt/SoftwarePackage-desktop/src/api/Pakages/DataRetriever.cs:line 24
   at MySoftwarePackage.Controllers.BusinessController.TestGet() in /Users/matt/SoftwarePackage-desktop/src/api/Controllers/BusinessController.cs:line 292
   at lambda_method(Closure , Object , Object[] )
   at Microsoft.AspNetCore.Mvc.Internal.ControllerActionInvoker.<InvokeActionMethodAsync>d__27.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at Microsoft.AspNetCore.Mvc.Internal.ControllerActionInvoker.<InvokeNextActionFilterAsync>d__25.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at Microsoft.AspNetCore.Mvc.Internal.ControllerActionInvoker.Rethrow(ActionExecutedContext context)
   at Microsoft.AspNetCore.Mvc.Internal.ControllerActionInvoker.Next(State& next, Scope& scope, Object& state, Boolean& isCompleted)
   at Microsoft.AspNetCore.Mvc.Internal.ControllerActionInvoker.<InvokeNextResourceFilter>d__22.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at Microsoft.AspNetCore.Mvc.Internal.ControllerActionInvoker.Rethrow(ResourceExecutedContext context)
   at Microsoft.AspNetCore.Mvc.Internal.ControllerActionInvoker.Next(State& next, Scope& scope, Object& state, Boolean& isCompleted)
   at Microsoft.AspNetCore.Mvc.Internal.ControllerActionInvoker.<InvokeAsync>d__20.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at Microsoft.AspNetCore.Builder.RouterMiddleware.<Invoke>d__4.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at Microsoft.AspNetCore.Hosting.Internal.RequestServicesContainerMiddleware.<Invoke>d__3.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at Microsoft.AspNetCore.Server.Kestrel.Internal.Http.Frame`1.<RequestProcessingAsync>d__2.MoveNext()

Answer 1

Rijndael / AES是一个块密码。

以128位（16个字符）块加密数据。加密填充用于确保消息的最后一个块始终是正确的大小。

您需要通过设置PaddingMode

显式设置加密和解密的填充

尝试将PaddingMode设置为PaddingMode.PKCS7

此外，将您的密钥设为16个字符的块（16,32等）

Answer 2

我认为该行

     Buffer.BlockCopy(fullCipher, iv.Length, cipher, 0, iv.Length);

实际应该是

     Buffer.BlockCopy(fullCipher, iv.Length, cipher, 0, cipher.Length);

您并未设置所有密码。

编辑以取悦学童：

这假定您通过提取前16个字节用作初始化向量并使用下一个32作为密钥来创建加密密钥。

如果你在两种情况下对称地使用了16，那么我还没有找到它为什么不起作用的线索。

Answer 3

由于您似乎在尝试使用AES加密/解密，因此您应该在Nuget存储库（nuget.org）中查找现有库。有很多。

仅举几个受欢迎的名称：

SimpleAesEncryption https://github.com/ArtisanCode/SimpleAesEncryption

csharp-aes https://gitlab.com/czubehead/csharp-aes

每个README文件中都有一些使用示例。

Answer 4

使用相同的代码遇到同样的问题，感激地从http://mikaelkoskinen.net/post/encrypt-decrypt-string-asp-net-core借来。我发现如果原始明文超过16个字符（字节？），这将抛出上述异常。无论如何，修复是：这一行：

var cipher = new byte[32];

应该是：

var cipher = new byte[fullCipher.Length - iv.Length];

然后，这一行：

Buffer.BlockCopy(fullCipher, iv.Length, cipher, 0, iv.Length);

应该是：

Buffer.BlockCopy(fullCipher, iv.Length, cipher, 0, cipher.Length);

正如凯文先前所说。

C＃加密成功，不会解密

4 个答案: