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Didactic Scrambled Egg Cipher Pre-Warmup Challenge
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snibril



Joined: 26 Oct 2008
Posts: 31

Post Didactic Scrambled Egg Cipher Pre-Warmup Challenge Reply with quote
I think there is an error in the line
eggs ^= (key[eggs&0x4]<<Cool;
It should be
eggs ^= (key[eggs&0x3]<<Cool; ?
Wed Nov 05, 2008 2:33 pm View user's profile Send private message
macz



Joined: 25 Oct 2008
Posts: 5

Post Reply with quote
yes i think the same
looks like an error
Wed Nov 05, 2008 2:39 pm View user's profile Send private message
MerickOWA



Joined: 07 Apr 2008
Posts: 182
Location: HkRkoz al KuwaiT 2019 HaCkEr 101

Post Reply with quote
Seems to be more wrong than that.

The few bits which are easily determined in the key are not consistent... or the encrypted data is not text. I'm betting on the former.
Wed Nov 05, 2008 3:27 pm View user's profile Send private message
tails



Joined: 10 Jun 2008
Posts: 191
Location: Tokyo

Post Reply with quote
Yes. It seems there is a problem in this challenge. Although it's actually solvable, it cannot be as adum intends. I've pointed out the problem on solvers forum, so we might better wait until it get fixed. I can't write the details here because it would spoil the challenge.
Wed Nov 05, 2008 8:03 pm View user's profile Send private message
adum



Joined: 19 Apr 2007
Posts: 391

Post Reply with quote
i think i've fixed it and uploaded a new version. please let me know if i messed up again...
Wed Nov 05, 2008 10:06 pm View user's profile Send private message Visit poster's website
snibril



Joined: 26 Oct 2008
Posts: 31

Post Reply with quote
Works now.
Thu Nov 06, 2008 2:02 pm View user's profile Send private message
cafelatte



Joined: 27 Oct 2008
Posts: 3

Post Reply with quote
(Puzzled) i worked some time on one with a 16-byte-key and ...(key[eggs&0xF]<<Cool;...
has that been substituted?
Sun Nov 09, 2008 8:51 pm View user's profile Send private message
tails



Joined: 10 Jun 2008
Posts: 191
Location: Tokyo

Post Reply with quote
cafelatte wrote:
(Puzzled) i worked some time on one with a 16-byte-key and ...(key[eggs&0xF]<<8);...
has that been substituted?


Now there are (at least) three versions:
- Didactic Scrambled Egg Cipher
- Didactic Scrambled Egg Cipher Warmup
- Didactic Scrambled Egg Cipher Pre-Warmup

And we have to solve them in the reverse order of their appearance. You have been working on the first one, but now you have to solve Pre-Warmup and Warmup beforehand.
Sun Nov 09, 2008 9:57 pm View user's profile Send private message
m!nus



Joined: 28 Jul 2007
Posts: 202
Location: Germany

Post Reply with quote
eggs ^= (key[eggs&0x3]<<8);

does the key[..] only pick one byte?
doesn't it in combination with <<8 make the the value eggs gets XORed with 0x0000??00 then?
Sat Dec 06, 2008 2:23 pm View user's profile Send private message
ghostbear



Joined: 31 Oct 2008
Posts: 1

Post Reply with quote
Code:
eggs ^= (key[eggs&0x3]<<8);



reads as:

Code:
eggs = eggs ^ ( key[eggs&0x3] << 8 )


also remember that key is an array with 4 bytes, so the term picks one of the 4 bytes and shifts that by 8 (so it masks the middle of the 3-byte tuple of plain text characters).




no, i have not yet solved this one...
Thu Dec 11, 2008 8:58 am View user's profile Send private message
cutter



Joined: 12 Jan 2009
Posts: 17

Post Reply with quote
i have just one question:

does " for (int eggs = {each 3-byte tuple in plaintext}) " mean that i should consider 000102, 030405 ,060708 for the plaintext 00010203040506070809 in hex?
Sun Feb 22, 2009 10:25 pm View user's profile Send private message
nighthalk



Joined: 31 Jul 2009
Posts: 41

Post Reply with quote
i doubt its actually "plain text" or that would be one hell of a coincidence to come out as perfect hex only characters after encryption, my only question is what eidean is this? is it going from 382d817119a1
-> 0x38 + 0x2d<<8 + 0x81 << 0x10
or 0x81 + 0x2d<<8 + 0x38<<0x10
Wed Aug 05, 2009 2:33 am View user's profile Send private message
Zeta



Joined: 16 Apr 2009
Posts: 62

Post Reply with quote
It's the first.
Wed Aug 05, 2009 7:27 am View user's profile Send private message
satfreak666



Joined: 16 May 2011
Posts: 11

Post Reply with quote
Hi there,

I'm a little confused about this challange.

As posted above, the encoding of the byte-sequence is Little-Endian. Can someone confirm, that encoding the message:

This is a secret message

with the key "0x11, 0x12, 0x13, 0x14"

will output

"2eafc48a26248a2625402cc4c8aca52a264528ec26a8aee5"

I can encode/decode it without any problems.

But brute forcing the challange-message produces no output. Is the decrypted message plain Text?
Thu May 19, 2011 7:45 am View user's profile Send private message
laz0r



Joined: 04 Feb 2010
Posts: 290
Location: Within the depths of Unix

Post Reply with quote
I make it "53454953c39851c39833420a13463a52c3a0b6c65a", but then I haven't actually solved the challenge successfully yet so this may well be wrong.

_________________
There is no spoon.
Thu May 19, 2011 8:33 am View user's profile Send private message
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