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Encrypting programs?
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oib111
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PostPosted: Sun Aug 19, 2007 2:23 pm    Post subject: Encrypting programs? Reply with quote

Plain and simple. How do I encrypt certain things in programs. Like passwords, id's, stuff like that?
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cigs dont make people high, which weed does, which causes them to do bad stuff. like killing


Last edited by oib111 on Sun Aug 19, 2007 2:47 pm; edited 2 times in total
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PostPosted: Sun Aug 19, 2007 2:30 pm    Post subject: Reply with quote

make another check? and a check to that?
u said "how can i check if the check was changed"
so... u can change the check of the check of the check of the check etc...
i guess u can make a value that always changes and checks the check? O_o
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UnLmtD
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PostPosted: Sun Aug 19, 2007 2:31 pm    Post subject: Reply with quote

Well if you want to do it they way you described, you could check the opcodes at the address.
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Last edited by UnLmtD on Sun Aug 19, 2007 2:33 pm; edited 1 time in total
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oib111
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PostPosted: Sun Aug 19, 2007 2:31 pm    Post subject: Reply with quote

I mean the check in the program that checks for the password and id. I want to make a check to see if they changed that check ^^

Ex.

Someone changed JE to JNE

Someone changed JNE to JE

Edit:

I figured it out. I was thinking. Well, why not go into olly and change a program and see what it was. But before I even did that I remembered godmode(good 'ol godmode). Which struck when I first learned direct byte. When godmode was at JE its bytes started with 74, and when it was JNE it was 75. So I just check for that change on the first byte. And I realized that nop was equivalent to DB 90 90 90, so just check for 90 instead of 0...

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cigs dont make people high, which weed does, which causes them to do bad stuff. like killing


Last edited by oib111 on Sun Aug 19, 2007 2:42 pm; edited 1 time in total
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UnLmtD
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PostPosted: Sun Aug 19, 2007 2:41 pm    Post subject: Reply with quote

I don't know if you got me, what I meant is check the opcode at your address if it is what you want. If I'm not wrong, JE = 0x74 JNE = 0x75
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oib111
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PostPosted: Sun Aug 19, 2007 2:46 pm    Post subject: Reply with quote

I was going for that too, but since I'm reading bytes I can't do that. And I just said JE = 74 and JNE = 75.

Ok, this thread is now going to be about encrypting programs!

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cigs dont make people high, which weed does, which causes them to do bad stuff. like killing
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hcavolsdsadgadsg
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PostPosted: Sun Aug 19, 2007 2:46 pm    Post subject: Reply with quote

UnLmtD wrote:
Well if you want to do it they way you described, you could check the opcodes at the address.


I'm pretty sure thats the idea, but then all you'd have to do would be stop this first if you were really so bent on getting information from it.

Also all those values are in hex, so remember to do the math, and DB = defines a byte and that's 3 nops right there.


Last edited by hcavolsdsadgadsg on Sun Aug 19, 2007 2:50 pm; edited 2 times in total
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PostPosted: Sun Aug 19, 2007 2:49 pm    Post subject: Reply with quote

actully nop is 0x90 not 90 90 90... thats nop nop nop
but u can nop that check... O_O
well why would we want to do that..?
and if u want to make the check work u gotta check bytes 0x90 if thats what u've done :O
what if u change it to db dd? xD

edit:
now that u edited ur post...
there are few ways... i know only 1 O_o
it sux... so.. :O
i use 2 variables (or more...) and then make like

var
var1:=Integer, String;
var2:=Integer, String;
begin
var1:=z0mg
var2:=lolz
if Edit1.Text = Var1+var2+'1337' then

so if password is z0mglolz1337 then...
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oib111
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PostPosted: Sun Aug 19, 2007 2:58 pm    Post subject: Reply with quote

Um, I was talking about assembly. In assembly nop is equivalent to db 90 90 90...and I edited the post because I solved the problem and I have a new one...
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cigs dont make people high, which weed does, which causes them to do bad stuff. like killing
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sponge
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PostPosted: Sun Aug 19, 2007 3:03 pm    Post subject: Reply with quote

CRC...
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kittonkicker
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PostPosted: Sun Aug 19, 2007 3:06 pm    Post subject: Reply with quote

Make your program generate an MD5 hash of the .code section, and then create a thread to watch it.

If at any point the MD5 != the MD5 you stored, crash the process!
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PostPosted: Sun Aug 19, 2007 3:11 pm    Post subject: Reply with quote

what..? english?
i understand the last part but if MD5 = lets say 1337 then MD5 = 1337 which = MD5 so therfore MD5 = MD5?
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PostPosted: Sun Aug 19, 2007 3:13 pm    Post subject: Reply with quote

I'm not gonna teach this guy how to code...
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TheSorc3r3r
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PostPosted: Sun Aug 19, 2007 4:45 pm    Post subject: Reply with quote

Search the crackme section for Uligor's second crackme, good example of encryption.
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DeletedUser14087
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PostPosted: Sun Aug 19, 2007 5:51 pm    Post subject: Reply with quote

The best crackme source ever

Code:

If edit1.text := 'Password' then
Showmessage('Cracked!');


Laughing
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