PHP - Hash contents of uploaded file

Question

I would like to hash the contents of an uploaded file in MD5. The file will not be saved locally so it only exists in a tmp directory.

How can I do this? Thanks.

think there is `md5_file()`? See this [question](http://stackoverflow.com/questions/2304081/php-get-the-md5-of-remote-file) Also you may want to use a stronger hash like SHA that will have less possibilities of collisions. — gideon, Apr 06 '11 at 19:47
See the second answer here. : http://stackoverflow.com/questions/770900/is-md5-less-secure-than-sha-et-al-in-a-practical-sense — gideon, Apr 06 '11 at 19:48
This is just for debugging. Only up to 3 files will be stored so I don't need to worry about collisions. I different hashing function will be used in the final, I just need to make sure the rest of it works. — A Clockwork Orange, Apr 06 '11 at 19:50
Just as a note, hashing a file in md5 does not provide storage ability - its use is more for file verification. You cannot 'decode' the md5 hash to create a usable file. — 65Fbef05, Apr 06 '11 at 19:51
65Fbef05, Thank you but I understand how hashing functions work :] — A Clockwork Orange, Apr 06 '11 at 20:22

score 21 · Accepted Answer · edited May 23 '19 at 07:45

21

You can use md5_file() or sha1_file() function. For example, if your post variable is filevar:

$myhash = md5_file($_FILES['filevar']['tmp_name']);

edited May 23 '19 at 07:45

Muhammad Hassaan

answered Apr 06 '11 at 19:47

Charles Brunet

score 3 · Answer 2 · answered Apr 06 '11 at 19:46

3

You can use md5_file(), even on your temporary file.

answered Apr 06 '11 at 19:46

Pascal MARTIN

score 2 · Answer 3 · answered Apr 03 '13 at 19:48

2

MD5() for string and md5_file() for files

answered Apr 03 '13 at 19:48

Thoman

3 Answers3