TripleDES 加密和解密给出奇怪的结果

我有一个有效的实施TripleDESCng（针对一些测试向量进行测试），但会发生以下情况：

当我加密纯文本时This is a sample message（24 字节，因此这将是 3 个块）（十六进制为5468697320697320612073616D706C65206D657373616765）用一个示例键，我得到E81F113DD7C5D965E082F3D42EC1E2CA39BCDBCCBC0A2BD9。但是，当我使用相同的示例密钥解密它时，我得到5468697320697320612073616D706C650000000000000000，当转换回 ASCII 时，为：

This is a sample.

除了我的代码之外，还有什么原因会导致这种行为吗？为了加密和解密，我使用 24 字节密钥（ECB 模式）。

EDIT:

using (var tripleDES = new TripleDESCryptoServiceProvider())
{
   byte[] data = ASCIIEncoding.ASCII.GetBytes("This is a sample message");
   Console.WriteLine(BitConverter.ToString(data));
   tripleDES.IV = new byte[tripleDES.BlockSize / 8];
   var encryptor = tripleDES.CreateEncryptor();
   byte[] result = new byte[data.Length];
   encryptor.TransformBlock(data, 0, data.Length, result, 0);
   var decryptor = tripleDES.CreateDecryptor();
   byte[] result2 = new byte[result.Length];
   decryptor.TransformBlock(result, 0, result.Length, result2, 0);
   Console.WriteLine(BitConverter.ToString(result2));
}
Console.ReadLine();

With almost all modes¹, you should make sure that the final part of your data is pushed through TransformFinalBlock rather than TransformBlock², to make sure it knows that no more data is coming and to ensure final blocks are flushed/written.

一般来说，假设输出大小将与输入大小匹配是不好的形式。

模式不是问题，IV 都设置为 0

Yes, that'll mean that the first block was not affected by your choice of Mode. But all subsequent blocks will be, because they will use the chaining mode and the previous block, not the IV. So if you want ECB (you shouldn't³) you need to explicitly set that mode.

¹Your code is using CBC, not EBC as you claim in your narrative. CBC is the default mode for .NET encryption classes.

²And when using this second method, pay attention to it's return value, as mjwills commented.

³You've picked an outdated crypto algorithm, paired it with an outdated mode of operation, and your words I've quoted above mean that you don't understand modes. Added together, I would suggest that you're not well placed to be writing code that uses crypto currently. The .NET classes can make it seem easy to write crypto code but you still have to understand how to make good choices in using them. Better to spend more time on researching these things before writing code.