Shannon's Journal Discussion Volume 3

[Raz]

Your filename doesn't match. Instead of bracets you have got %28 and %29 in the filename. This is because of different charset. If you replace %28 with "(" and %29 with ")" your MD5 should match again, as filenames are part of the whole MD5 sum. If it then still doesn't match then the files are broken.

Just for the sake of completeness: the filename is independent of the md5sum. Or to make this more correct: The md5sum of a file is not influenced by its filename.

Hmm...that's strange, because I got the correct hash after renaming the file on my phone in the way I described.

It is possible to include external metadata like filename, timestamp, permissions, etc. into the hash calculation using the MD5 algorithm per se. If calculated that way changing the filename (or other metadata) would change the calculated hash value.

BUT: Shannon is using the software md5sum (take a look at any hashvalue.txt for subliminals have near by - the content is a terminal printout showing the execution of a command with said software), which explicitly does not include external metadata of a file when calculating the hash value. Thus the hash values that Shannon provides us with don't change when we alter the metadata (filename, permissions, timestamps) of those files. Unless your software alters the file as well in some way. Which is why we get the hash values in the first place

edit: Container-specific metadata such as ID3 tags on the other hand are stored in the file itself, so I guess the hash values will change, when you edit this kind of metadata. But I haven't tested that myself, so this is more of an educated guess.