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Same Files but Different Hashes

PostPosted: 01 Jun 2010 09:20
by siavoshkc
Take a look at the picture. I am 90% sure files are the same. But each of them has a different hash. One has a SHA1 but not eD hash and vice versa. Some of them have different eD hash although they are identical files.

Of course when the hash is different there is something different in the file. For example if one user adds artist to mp3 metadata it may change file hash.

Here I don't know what to say. But its a problem because one file with 10 sources will be shown 10 files each with one source.

Re: Same Files but Different Hashes

PostPosted: 03 Jun 2010 21:18
by roestvrijstaal
I couldn't see the image, so i had to base my answer on your text.

ED2K uses MD4-algorithm for hashing, which has been 'cracked'/ found out to be too weak.

As far as i know and read on wikipedia the SHA-1 is not 'really' cracked, but some weaknesses are detected.

It's difficult so solve, or we have to replace SHA-1 with it's longer variants such as SHA-224, SHA-256, SHA-384 en SHA-512, or with it's successors SHA2 or SHA3...

Or just only hash the video & music stream and not the metadata of the file, instead of the whole file.

Re: Same Files but Different Hashes

PostPosted: 04 Jun 2010 08:37
by siavoshkc
Picture was 5 files in download window with same name and size but different hash and source.

Re: Same Files but Different Hashes

PostPosted: 04 Jun 2010 17:37
by ailurophobe
I don't understand what the problem is... The hashes are what G2 and ED2K identify files with, if the hashes are different then for all practical purposes they are different files. Even if they actually were the same file, there would be nothing Shareaza could do about it. And if they have a different ED2K hash they really are different files; the reason the MD4 hash is considered weak is because it is theoretically possible to generate a different file that has the same hash. Identical files still always have the same hash. (Barring software bugs or hardware failures.)

Re: Same Files but Different Hashes

PostPosted: 04 Jun 2010 18:24
by old_death

Re: Same Files but Different Hashes

PostPosted: 02 Mar 2017 16:01
by wdc
Hello i found this topic @ google when i was looking for the answer to this question:
When i download file via shareaza and rename file + move to different directory, will file get different hash after i share it in Shareaza?

Re: Same Files but Different Hashes

PostPosted: 02 Mar 2017 19:25
by queuesclimber
No. The filename did not touch the hash. You can rename it what you want.
But you will really run into trouble if you search by hash, and getting different file names.

Please read the post before your question.