c# - 使用校验和验证收到的文件

Question

我需要使用 Web 服务传递文件（我可以控制 Web 服务）。为了满足安全要求，我需要确保传递的文件没有被修改或损坏。我打算像下面那样做。

1. 将我的文件转换为byte[]

2. 计算哈希，

   System.Security.Cryptography.MD5.Create().ComputeHash(stream);

3. 传递文件

当我将文件（字节数组）传递给 Web 服务时，传递我的哈希值是一个好习惯吗？

还是我需要按照其他流程来检查文件？处理这个问题的最佳方法是什么？

Answer 1

If it's a security requirement, sending the MD5 sum along with the file is probably not what you want to do: anyone who can intercept the file can also rewrite the checksum as well.

I use CRCs, instead: they are somewhat more sensitive to small changes in a file (or stream's) contents, and they are more compact and easier to compare. .NET doesn't appear to have a CRC implementation, but I found a nice one online that appears to work well, Calculating CRC-32 in C# and .NET.

Does your client have the capability of computing the checksum independently on its side as well?