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[keygenme] Alive


HMX0101

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  • 1 month later...

Is this ElGamal Signature Scheme? It looks like it.

Anyway, attempting to solve DLP to get the private key

gives me: "Can't solve that sh*t!" :(

Never solved ElGamal (or DLP) before, so I'm a newbie in that area.

I've identified all the FGInt calls and stuff and know what it's doing,

but don't know how to reverse it.

First thought was to generate first 2 parts of serial randomly and

then solve 9F76B9617C4B04782B89 ^ X mod E50D80BB9284DF3F23D3 = Y to

get the 3rd part, where X is the 3rd part of serial and Y is calculated

based on 1st and 2nd part of serial and name. But solving DLP every time is unfeasible.

-- EDIT --

Been trying to get the private key by solving the DLP (using another DLP solver)

for 3 hours now and still nothing. I must be doing something wrong.

Guess I'm not the only one having difficulties with this one, considering it's still unsolved.

-- EDIT --

If this is indeed ElGamal, then am I correct with the following?

Y = G ^ X mod P, where G,P,Y are public keys and X is the private key.

Y = E17D4BC428ED77A25829

G = 9F76B9617C4B04782B89

P = E50D80BB9284DF3F23D3

Edited by Saduff
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You're correct, those are the values for P,G,Y.

About the DLP solving time, I would recommend you to use a solver based on Index Calculus method.

  • Like 1
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Thanks, I found a calculator that solved the DLP in 0.5 seconds. :D

Now let's see if I can keygen this thing. :)

-- EDIT --

Now I don't understand what the 3rd part of the serial (last 20 chars) has to be. :D

I think that the first 2 parts of the serial are the signature (r, s).

The 3rd part of the serial is used only here: G ^ serial[3] mod P, so I thought that

it has to be MD5(name), but that can't be, since MD5 is 32 chars long.

So I tried using MD5(name) mod P as the 3rd part of the serial, but that didn't work. :unsure:

Edited by Saduff
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The third part of the serial is part of the signature.

Difficulty of the challenge is to find out what the third part should be :^

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  • 2 weeks later...
  • 4 weeks later...

Thanks, I found a calculator that solved the DLP in 0.5 seconds. :D

Now let's see if I can keygen this thing. :)

Care to share that tool, or give me/us a link for it? :)

I have been looking for a dlp solver using the index calculus method for a while now.

Maybe I'm just a bad googler :turned:

- rdbnhoax

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I used Magma Calculator:

http://magma.maths.usyd.edu.au/calc/

Used this script:

p := 1081671008419063856571347;
K := GF(p);
g := K ! 753046344671602713045897;
y := K ! 1064843761188532526405673;
x := Log(g, y);
x;

Don't know if it uses the index calculus method, but it solved the DLP very fast, while other solvers failed.

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yeah, really nice scheme :)

thanks to KKR, for informing me, that it's a special signature scheme, so could be solved more effective way, rather than runtime DLP solving for each signature. So I wrote the equation with pen and got the result

for those, who are interested how to get signing algorithm without searching for some common schemes:

69j5h5.jpg

maybe I'll solve this kgm soon, once i get bored. :)

Edited by qpt^J
  • Like 1
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KKR_WE_RULE

I got freak'd out by the serial decoding algo :P

May be if I get bored some time, I'll touch it again :D

way to go qpt :) do it !! :)

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KKR_WE_RULE

Okie.. I got bored & I touched it again.. This time I recoded ya Serial Decoding stuff in Delphi.

Here it is.

http://pastebin.com/Gqyw9DLz

Accoriding to my logic.. It should be reversed as Under, but it isn't working.

http://pastebin.com/Tw30Vtqv

Any 1 else having this prob ?

Edited by KKR_WE_RULE
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  • 1 month later...

Nice job mate, wasn't that hard, huh? ;)

Btw, my intention was to use 'FUN' as first 3 chars... I didn't thought about other possible words :P

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for me, it was hard, yeah :)

especially that Lexicographical order part, because there wasnt any good explaination about it on inet, only by guessing i found how it works :P

and found that 'KEY' part by guessing too :)

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That transformation part kick'd my *** :P Real thanx goes to Dcoder__. I couldn't identify the algo there.

Ok.. now it can be made public.. Its BWT De_Transform() that used there. Need to use BWT_Transform() to reverse it :)

@qpt^J : Great work as always :) Congratz :)

@HMX : I'll still write a soln, coz last time I tried I had some probs with the BWT_Transform(). It was hard for me.. but I have gotta admit, it taught me a great deal of stuff. Thanx a bunch :)

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  • 4 years later...
SmilingWolf

I'm years late as always D:

I'm including the modified ElGamal signature's paper, my notes (in italian, sorry), the (probable) original Delphi BWT source used in the KeygenMe, a sorta equivalent implementation in Python found on the net and most importantly my keygen in Python. Uses Z3Py to retrieve the first three letters of the serial :)
Also included a version with the precalculated string in case you don't want to install and configure Z3Py. The other dependencies are standard Python 2.7 modules.

EDIT: finally added to my KGCollection. Relevant sources: BWT, keygen.

Alive.7z

Edited by SmilingWolf
  • Like 2
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