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Didactic XOR Cipher
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zero0cripton



Joined: 21 Jan 2010
Posts: 6
Location: Portugal

Post Didactic XOR Cipher Reply with quote
is there any chance that the site is not working well? i think that i have figured out the answer and still it won't let me go through. Can anyone send me the answer on a PM or just give me some tips on this?

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Sex is like hacking, you get in, you get out and you hope you didn't leave anything behind that can be traced back to you.
Sun Jan 24, 2010 6:52 pm View user's profile Send private message
yushun



Joined: 08 Apr 2010
Posts: 1

Post Reply with quote
remember the base format
Sun Apr 11, 2010 9:43 pm View user's profile Send private message MSN Messenger
Masti6



Joined: 15 May 2010
Posts: 55
Location: Finland, Nurmes

Post Reply with quote
I don't get this one.
XOR is something between AND and OR, right? Then how do I XOR something. I can't just OR / AND something into something else can I?
I'm so damn confused.
Someone explain the basic trick for XOR'ing(?) so I could figure it out myself. Thanks in advance.
Sat May 15, 2010 3:40 pm View user's profile Send private message MSN Messenger
CodeX



Joined: 17 Oct 2008
Posts: 350

Post Reply with quote
If you don't understand something you really should resarch
Sat May 15, 2010 4:02 pm View user's profile Send private message
Masti6



Joined: 15 May 2010
Posts: 55
Location: Finland, Nurmes

Post Reply with quote
Oh I've done my Researches. I just can't figure out how to use it in this example.

Some enlightening tips are appreciated. But thanks for the additional link to a page of what kind of I've seen too many so far. (<-- If that made any sense...)
Sat May 15, 2010 4:45 pm View user's profile Send private message MSN Messenger
CodeX



Joined: 17 Oct 2008
Posts: 350

Post Reply with quote
If you get both AND & OR then here's a breakdown with truth tables:
AND
0 0 → 0
0 1 → 0
1 0 → 0
1 1 → 1

OR
0 0 → 0
0 1 → 1
1 0 → 1
1 1 → 1

NOT
0 → 1
1 → 0

XOR
0 0 → 0
0 1 → 1
1 0 → 1
1 1 → 0

so in terms of AND, OR & NOT you'll find XOR can be expressed as (a OR b) AND (NOT(a AND b)) which is (a | b) & (~(a & b)) in C like languages, in these you're better off just using ^ though as that's the XOR operator. These operations are usually applied to strings of bits which turns out like:
Code:
 a  = 10100
 b  = 01110
a^b = 11010
Was that something more like that you wanted?
Sat May 15, 2010 5:29 pm View user's profile Send private message
Masti6



Joined: 15 May 2010
Posts: 55
Location: Finland, Nurmes

Post Reply with quote
I'm still working on the challenge, but thanks for an excellent and simplified tip (The Wikipedia article was horribly confusing).
I shall try bringing everything down to the binary level and trying to Decipher the code with that.
Thanks again!
Sat May 15, 2010 6:52 pm View user's profile Send private message MSN Messenger
erry



Joined: 11 Dec 2010
Posts: 13

Post Reply with quote
i did it, but it gave me a answer that isn't correct.
I took the number in HEX and turned into binary, than i XORed 79 (converted in binary too) at every number, then i put them together, but it's wrong...
Tue Apr 12, 2011 5:08 pm View user's profile Send private message
M4xZ3r0



Joined: 31 Mar 2011
Posts: 5

Post Reply with quote
erry wrote:
i did it, but it gave me a answer that isn't correct.
I took the number in HEX and turned into binary, than i XORed 79 (converted in binary too) at every number, then i put them together, but it's wrong...


Quote:
79 (decimal)
means it is decimal already.
Wed Apr 13, 2011 9:22 am View user's profile Send private message
erry



Joined: 11 Dec 2010
Posts: 13

Post Reply with quote
I know it's decimal, but i need to make him binary to XOR it
Wed Apr 13, 2011 12:19 pm View user's profile Send private message
Karian



Joined: 09 Jan 2008
Posts: 75

Post Reply with quote
For me, it is not really clear what you tried exactly.

What do you mean exactly with the every number and the put them together parts of your sentence? It is unclear what you have done exactly, and that makes it difficult to pinpoint the problem.
Wed Apr 13, 2011 1:03 pm View user's profile Send private message
erry



Joined: 11 Dec 2010
Posts: 13

Post Reply with quote
Well, i took the number given in HEX and i copied it in MS.Word.
After every number (or letter, because it's hexadecimal) i clicked Enter.
Then i changed every number (or letter blabla) to his value in binary. After that a XORed every binary number with 79.
I do an example hoping to not spoiler too much.
the number started with 3, so i XORed 0000011 with 1001111 (it's 79, in binary), and i obtained 1001100. I did it with every number but now i don't know how to proceed
Wed Apr 13, 2011 1:15 pm View user's profile Send private message
M4xZ3r0



Joined: 31 Mar 2011
Posts: 5

Post Reply with quote
erry wrote:
Well, i took the number given in HEX and i copied it in MS.Word.
After every number (or letter, because it's hexadecimal) i clicked Enter.
Then i changed every number (or letter blabla) to his value in binary. After that a XORed every binary number with 79.
I do an example hoping to not spoiler too much.
the number started with 3, so i XORed 0000011 with 1001111 (it's 79, in binary), and i obtained 1001100. I did it with every number but now i don't know how to proceed


In Decimal one Byte is one Character (or 2 or 3 ^^), in Hex one Character isn't one Byte.
Wed Apr 13, 2011 3:18 pm View user's profile Send private message
thewino



Joined: 06 Apr 2011
Posts: 5

Post Reply with quote
am i on the right track? hex to bin bytes xor backwards with 79 bin back to hex. this is not working for me. unless my calculations were wrong somewhere. ascii table needed perhaps?
Fri Apr 15, 2011 4:42 am View user's profile Send private message
M4xZ3r0



Joined: 31 Mar 2011
Posts: 5

Post Reply with quote
thewino wrote:
am i on the right track? hex to bin bytes xor backwards with 79 bin back to hex. this is not working for me. unless my calculations were wrong somewhere. ascii table needed perhaps?


I don't exactly know what you mean with "xor backwards" but it sounds like you're very close
Fri Apr 15, 2011 8:02 pm View user's profile Send private message
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