Hi,
it might sound weird,
but i need help reversing an algi i've coded,
someone that saw the algo
told me its reversable,
but i dont know how to reverse it..

if anyone can help me,
it would be great..

i've added the algo..

if anyone want to use it, you're welcome,
just say you're using it ;)

thanks,
ParaBytes
Posted on 2002-04-20 06:26:57 by ParaBytes
X,

I had a look at your algo but I don't have a clue at what it does, could you explain what its doing so someone can see if they can answer the question ?

Regards,

hutch@movsd.com
Posted on 2002-04-21 07:14:38 by hutch--
He is asking if his hash code is injective function.
In other words - if it is able knowing how the hash code (used to
create hash from data) works to recreate data having the hash.
Posted on 2002-04-21 07:24:00 by The Svin
The code takes a memory address,
and its size
and hash it into a weird thing,
i wanna know if its possible, and if it does, how,
to reverse the algo, so it would get the hash'ed
data,
and return the non-hashed data...

now, let me explain shortly the algo :

loop 1 :
get byte of data,
hash into dword

loop2 :
get dword,
hash into a new dword

loop3 :
checksum of data
into dword

i need to reverse the algo..
(loop1-loop2)
and keep the checksum..

so, if anyone can...
tell me.
Posted on 2002-04-21 07:54:52 by ParaBytes
ParaBytes,

are you trying to make the board help you with crackmes? ;)

or worse, in cracking a commercial prog? ;) ;)

ancev
Posted on 2002-04-21 10:22:45 by ancev
The algo is MY coded,
i've coded it for some program i'm making
and i need to decrypt it,
the only problem is i dont know how.

so, i came to a board with people who MIGHT have
a clue about what to do...

if i was needed to get a serial i'd bruteforce it.

its a pure MY code for a PURE FREEWARE code.

thanks for "support"
Posted on 2002-04-21 14:29:49 by ParaBytes
ancev,
don't make me laugh :)
injectivety is subject of interest on any serious mathimatics or programmers.
Go to math or programming book store and you can see 100s legal books discussion the subject. Where in 1000s exercizes you can see as a task to solve problem about checking if some function (hash or someting alike) is partialy or complitely injective.

If you are talking of cryptografy, then you must know that with open key cryptografy it is only for professional hackers to HIDE some discoveries about reentrance or injectivity of some hashing
of crypt function. Any who working in protection field tried immidially publish of known injectivity discovery in RSA or different functions. Only for real hackers (not that bullish boys but for those
pros who make money on it) is in their interest so that nobody knows of holes they found.

Open worldwide known AOP by D.Knuth (that any pro programmer read) - you can find 100s pages of hashing and injectivity.

Yet the US proud to have such a genius as D.Knuth and nodody has a stupid idea to call his book illegal. ;)
Posted on 2002-04-21 15:27:27 by The Svin
Svin, parabytes' code looks very much like something ripped out of
a crackme. Furthermore I think it's a bit weird he's written a
"hashing" function and knows it can be reversed but doesn't know
how to do it. Since PB also hangs out in cracking channels, well,
vecna's assumption wasn't exactly without reason ;).

While there's nothing wrong in reversing the algorithm, neither
morally or by the rules of this board, it *would* be wrong if it
was a piece of code ripped from an application, as we'd then have
reverse engineering.

But let's trust ParaBytes that it's his own code, the style is
messy enough that I believe it ;)
Posted on 2002-04-21 15:43:43 by f0dder
dude,
its my code, if i wanted it cracked why not brute/patch ?
anyway,
i THINK its reversable because soemone
that took a quick look told me it is,
but he dont has the time to reverse it,
and its beyond my abilities to reverse it.

so i came to a form of people who SUPPOSE to know good
enough asm and coding to reverse that algo.

and as f0dder said, it is pretty messy, therefore,
can be mine, and if it was a crackme code
why would i change the address to the original
var names ??

so it is my code.

please stop arguing and start reversing..
:)

ParaBytes
Posted on 2002-04-21 15:50:33 by ParaBytes
Guys,

I would not worry too much about the content, I downloaded X-Ware's (Parabytes) algo and it has nothing illegal in it and it is his own code so he has every right to post a cryptological question here if he wishes.

X,

When you post in this forum, just be careful about your terminology, when we hear "REVERSING" in here we tend to think of people "CRACKING" commercial software and that is not allowed here at all. This is why some of our members have asked you these questions.

Regards,

hutch@movsd.com
Posted on 2002-04-21 16:29:44 by hutch--
i don't know if this question is allowed or not, but would someone please explain what a "crackme" is? is it trying to get ppl to test your own code for free or somf?
Posted on 2002-04-21 20:54:21 by jademtech
crackme (= Crack Me) is a puzzle to test RE/cracking skills.
Posted on 2002-04-21 20:59:29 by bitRAKE

if i wanted it cracked why not brute/patch ?


maybe you want code a keygen ;)

heheh... just kidding

if this isnt a problem to the moderators, surely isnt a problem for me ;)

ancev
Posted on 2002-04-21 21:36:18 by ancev

crackme (= Crack Me) is a puzzle to test RE/cracking skills.


ah... thanks... i wonder if that's what happened to humpty dumpty?
Posted on 2002-04-21 21:37:48 by jademtech
The only reference to "CRACK ME" that may survive in this forum is one that has something to do with one person asking another to strike them. (Down market deviation of masochism) but if it is this type of topic, it will have to be placed in the heap and only if its fully wholesome squeaky clean reference. :grin:

Any other form of "CRACKME" will be seriously frowned upon and may end up magically disappearing. :mad:

The forum will allow discussion on encryption related design issues as information security is a valid form of programming but it will not be allowed to degenerate into thinly disguised cracking related issues. :alright:

Regards,

hutch@movsd.com
Posted on 2002-04-21 21:48:59 by hutch--
hutch--,
you CRACK ME up :grin:
Posted on 2002-04-21 21:52:27 by jademtech
ok,
lets stop that,
and help me ?

i just want to know if that 1 way hash
or 2 ways crypto.
and if it is 2 ways crypto, how to make decryption
routine...

that all.

ParaBytes
Posted on 2002-04-22 04:00:29 by ParaBytes
Your problem is a known problem - people see something working and say: stop, it's all wrong. Fullstop. Then they go... and you're here to struggle and fight, and what's even worse, you're going to doubt into yourself.

If you believe your algo is not revertable, try to create a challenge, put your code together and keep the source challenge. Then you go and ask people like us if we would be able to revert the result code. I am pretty sure the one who told you it would be revertable will not even try a single number. An algo is not revertable as long as no-one showed how.

Giovanni
Posted on 2002-05-06 17:32:22 by sch.jnn