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Cryptography Challenge #28!
Link | by gendou on 2008-01-12 04:23:36 (edited 2008-02-19 16:21:01)
Welcome to Gendou.com Cryptography Challenge #28!

The goal of this game is to find the encrypted message by gaining access to this page, then decrypt it.



hint 1
hint 2
hint 3

Scoreboard:


Re: Cryptography Challenge #28!
Link | by empoleon on 2008-01-12 05:02:57
pm sent, hope that was right... ^^v


Re: Cryptography Challenge #28!
Link | by on 2008-01-12 06:51:52
lolz, I just did a quick experiment and I'm not good at this but just want to try whatever I've found xD

so wish it was right..even tho it might not be lolz x.x;

Ohai.

Re: Cryptography Challenge #28!
Link | by gendou on 2008-01-12 12:53:49
This challenge has nothing to do with the bot-trap.php page.
That page is to prevent certain programs from damaging the site.
You might want to research user agent.


Re: Cryptography Challenge #28!
Link | by Anime on 2008-01-18 08:00:16 (edited 2008-01-18 08:02:05)
Hmm... Got into the page...
All I need to do is decrypt this...
But how?


Re: Cryptography Challenge #28!
Link | by gendou on 2008-01-18 09:17:27 (edited 2008-01-18 09:18:19)
If you're stuck, click on all the hints.
You should focus on using the 3rd hint supplied here to understand how the alphabet hint was generated.
Look for patterns and develop a theory to describe why you see them.
hint #4: think binary.


Re: Cryptography Challenge #28!
Link | by iamlagging on 2008-01-19 22:17:47 (edited 2008-01-20 08:37:11)
The fact that everything in the right column is 00 is not a coincidence is it?
If one of them were changed to 02 or 80, would the message still be the same?

Re: Cryptography Challenge #28!
Link | by gendou on 2008-01-20 12:21:16 (edited 2008-01-20 12:21:44)
There is no coincidence to it at all.
Changing the encoded message would change the decoded message, of course.


Re: Cryptography Challenge #28!
Link | by iamlagging on 2008-01-20 13:02:47
Since no one got it yet, and I'm totally stuck, I'm going to put out some ideas that I have had (this is after you can see the encrypted message).

Gendou, feel free to modify this if it reveals too much.

So the blocks of 8 probably refer to ASCII characters by their 8 digit binary numbers.

I hope the the alphabet hint is referring to lower case letters a, b, c, and d. Otherwise, I'll feel very stupid.

I'm guessing that the reason why all of the right column numbers are '00' is because the the written characters lie in the first 128 ASCII characters meaning that the first bit/digit is 0.

I tried some stuff such as assigning a 1 to and odd hex number and 0 to an even hex number but no luck there.

I tried doing some XOR operations to the hex numbers after changing them to binary but no luck there either.

If you assume that each hex number gives an output for a specific bit, (like the last hex number refers to the first bit. The 4th hex number refers to the last bit. Stuff like that) I think you get a contradiction.

Re: Cryptography Challenge #28!
Link | by gendou on 2008-01-20 19:44:49
yes, the encoded alphabet supplied is in lowercase.
xor is not used in this cipher.
the message is encoded, and thus also decoded, 8 bytes at a time.
each of these bytes is then interpreted as a string of 8 bits.
the way they are strung together should be visible by the alphabet key.


Re: Cryptography Challenge #28!
Link | by iamlagging on 2008-01-21 15:41:54 (edited 2008-01-21 15:48:15)
Ok, I can see that each hex number is 1 byte or 8 bits. So, converting to binary, 55 gives us "01010101" 66 gives us "01100110" etc... But when I get to "d," no matter what I think of, I keep getting some contradiction, So now what???

Re: Cryptography Challenge #28!
Link | by gendou on 2008-01-21 15:47:14 (edited 2008-01-21 15:47:56)
Right.
The pattern you uncovered is plainly visible, now you have to figure out how it was generated using the alphabet.
Remember, the message is encoded/decoded 8 characters at a time.


Re: Cryptography Challenge #28!
Link | by iamlagging on 2008-01-21 15:49:25
The message is encoded 8 CHARACTERS at a time? Or did you mean 8 bytes?

Re: Cryptography Challenge #28!
Link | by gendou on 2008-01-21 15:53:08
using ascii, one character = one byte
:)


Re: Cryptography Challenge #28!
Link | by on 2008-01-21 18:46:37
The 8 bytes and 8 characters at a time is indeed a nice clue Mr. Gendou. I really had a nice decoding experience... Ü

(Yay!!! At last I got it first... Ü)

ÜÜÜ Please save the Earth!!! Stop the use of CFC's and let us rebuild the ozone layer. ÜÜÜ

Re: Cryptography Challenge #28!
Link | by iamlagging on 2008-01-22 09:11:10 (edited 2008-01-22 09:12:51)
I still don't see the pattern.

55 66 78 80 00 FF FF 00 converted to binary should give us something like
0 1 0 1 0 1 0 1
0 1 1 0 0 1 1 0
0 1 1 1 1 0 0 0
1 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0
1 1 1 1 1 1 1 1
1 1 1 1 1 1 1 1
0 0 0 0 0 0 0 0

But I don't see a pattern here that is consistent with the other binary numbers that are generated by the hint. It's frustrating when you feel like you're ONE breakthrough away from solving a puzzle.

Re: Cryptography Challenge #28!
Link | by gendou on 2008-01-22 10:22:44
Dude, you're so close. Look at it sideways.


Re: Cryptography Challenge #28!
Link | by iamlagging on 2008-01-22 14:26:32 (edited 2008-01-22 14:43:44)
EDIT: OMG!!! I got it finally. I'm retarded... Now just work to do

Re: Cryptography Challenge #28!
Link | by DeG on 2008-01-23 03:53:01

Ah I got it...nice clues. But its gonna take a while and lots of work, haha.



kenshin

Re: Cryptography Challenge #28!
Link | by iamlagging on 2008-01-23 16:03:19
You have no idea how stupid I felt when I figured it out; I interpreted the hint on the alphabet wrong. That's why it took me as long as it did.

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