View Full Version : possible to get the string(file) from md5 hash
highfly
April 18th, 2004, 17:13
possible to get the string(file) from md5 hash
something like getting 1kb file from the 16 bytes md5 hash,this md5 has is calculated from that 1kb file,possible?
for example
Text is : woodmann
md5 hash for woodmann is : 1B C6 BD 2E C2 0A AC 23 4B 59 84 C4 48 74 41 97
now possible to get the text(woodmann) from that md5 hash
dELTA
April 18th, 2004, 17:32
No, the purpose of cryptographic hashes is to prevent just that (not to mention that for longer generic data strings like e.g. 1 kb it would be theoretically impossible to compress them to 16 bytes under most circumstances, just imagine how incredibly good data compression algorithms that could be derived if that would be possible).
The best you can do is to bruteforce all possible source strings inside a given length range.
highfly
April 18th, 2004, 17:44
the file loading strings are unencrypted in exe with foldername,filename,extention are in different location in exe,when the program is executed it joins foldername,filename,extention and creates md5 hash then it loads the file by checking the hash in the file,anyway to get foldername,filename,extention with the hash
dELTA
April 19th, 2004, 08:53
Surprisingly enough, as it happens, Windows file paths are not an exception to what I just said about hashes, no...

highfly
April 19th, 2004, 13:01
any idea how exe joins the file and folder names which is at different location in exe
dELTA
April 19th, 2004, 13:10
By copying them to a buffer in the memory?
highfly
April 19th, 2004, 13:23
to load a file it uses the path and filename in exe,btw the files loaded are from a pack file which does'nt have names,it identifies with hash
process
get the filename and folder name
join those and make a string
with the string it calculates md5
now it loads the correct file from the pack file with that md5 hash
any possible method to crack this function
dELTA
April 19th, 2004, 19:09
Exactly in what way would you like to "crack" this function, you must be much more specific and give much more details to get any real help. What are you trying to accomplish, and why? How did you get the information you currently have?
Also, if the files are extracted only based on these "md5 hashes", there can only be a finite number of predetermined static hashes (i.e. a lookup-table) for files to extract from that archive, since there is no way for the application to reverse that hash and determine the original path from it.
How do you know it's an md5 hash at all? Are you sure it's not just some sort of encrypted data?
Also, why don't you just capture any file you like when the program extracts them itself? Modify the input to that "hash" function during runtime if you can't get the program itself to request the files you want from that library.
And remember, MUCH more details now if you want any further help!
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