PHP md5_file hash is not the same as other online hash generators

Question

I am uploading a file using PHP which uses md5_hash to create a MD5 hash of the file.

When I upload that same file to other online MD5 hash generators they return something else.

Is there something I am doing wrong?

$MD5 = md5_file($_FILES['inputname']['tmp_name']);
var_dump($MD5);

string(32) "d41d8cd98f00b204e9800998ecf8427e"

https://md5file.com/calculator says:

MD5 3be70563560066c0751a8e9427949bbf

Have you tried `$MD5 = md5($_FILES['inputname']['tmp_name']);`? — Funk Forty Niner, May 29 '14 at 18:03
Yes, this gives another hash. If I just use md5() without getting the file contents I am simply hashing the temp filename. — JonathanBristow, May 29 '14 at 18:08
Maybe the other online hash generators are resampling the file (scanning for viruses, etc.), hard to say why it does that. — Funk Forty Niner, May 29 '14 at 18:10
I thought that too, but I tested 3 different hashers and they come up with the same hash. — JonathanBristow, May 29 '14 at 18:15
Maybe that online calculator uses `md5` instead of what you're using `md5_file` and uses different algos. That's all I can think of. — Funk Forty Niner, May 29 '14 at 18:25

score 0 · Accepted Answer · answered May 29 '14 at 18:28

0

d41d8cd98f00b204e9800998ecf8427e is the MD5-hash of the empty string. This means that the file that the filename $_FILES['inputname']['tmp_name'] points to is empty.

So, there is a major problem with the upload somewhere... maybe a server configuration error. It's impossible to say though, without further investigations.

answered May 29 '14 at 18:28

Michael

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You are correct. There was an issue with the PHP configuration which was clearing the cache before I could get to the posted file. – JonathanBristow May 29 '14 at 20:20

PHP md5_file hash is not the same as other online hash generators

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