CODEWITHSUNDEEP
c#filehashcopy
DarkShadow
DarkShadow

Reputation: 185

file copy that won't change file hash

I'm having trouble copying a file and then verifying the integrity of the file afterward. I've tried every file copying method I can think of (File.Copy, filestreams, trying to do a binary copy) but the file hash is always different after the copy. I've been searching around and I notice a lot of people saying that copying a file from a network share can cause this but I get the same results from shares as I do just straight from my hard drive.

//File hashing method:
private byte[] hashFile(string file)
{
    try
    {
        byte[] sourceFile = ASCIIEncoding.ASCII.GetBytes(file);
        byte[] hash = new MD5CryptoServiceProvider().ComputeHash(sourceFile);
        return hash;
...

Using this method the origional file and the copied file always produce the same hash (individually) through every run but the two hashes are not the same. Does anyone know of a way to copy files without changing the file hash?

Upvotes: 0

Views: 2781

Answers (2)

Sjoerd
Sjoerd

Reputation: 75599

It seems you are passing the filename instead of the file contents to the hash function.

Use something like this:

byte[] hash = md5.ComputeHash(File.ReadAllBytes(filename));

Or this:

using (var stream = File.Open(filename)) {
    byte[] hash = md5.ComputeHash(stream);
}

Upvotes: 3

Tomer W
Tomer W

Reputation: 3443

I Think you are Hashing the FileName .. and not Content !

so sure it wont compute as same!

check the Value and Length of file and byte[] sourceFile

Upvotes: 3

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