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All Sound Same
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lukas



Joined: 26 Nov 2008
Posts: 34
Location: Germany

Post All Sound Same Reply with quote
Dear gfoot can you give any hint what to do to solve this challenge Question
Tue Dec 02, 2008 8:00 pm View user's profile Send private message
gfoot



Joined: 05 Sep 2007
Posts: 269
Location: Brighton, UK

Post Reply with quote
I knew it was kind of hard, but I'm surprised nobody has solved it yet. This one was actually just a warm-up - I sent adum a much more complex one too! I thought tails would solve this simple one within 24 hours or something. Maybe he just hasn't seen it yet... Smile

It's an old-fashioned technique, and not very sophisticated, but its cryptanalysis method doesn't show up much either on Google or in the only book I own on cryptography. As such, I think you'll need to roll your own algorithms for solving it.
Tue Dec 02, 2008 10:04 pm View user's profile Send private message
tails



Joined: 10 Jun 2008
Posts: 191
Location: Tokyo

Post Reply with quote
Thank you for your expectation, but I have already spent several hours for this challenge. Hmmm... I'll try harder.
Tue Dec 02, 2008 10:37 pm View user's profile Send private message
fridolin



Joined: 30 Nov 2008
Posts: 16

Post Reply with quote
I think i got the type of chipher (as always: just consider the caption) - but the cryptanalysis is really hard.
Wed Jan 28, 2009 9:09 am View user's profile Send private message
rmplpmpl



Joined: 26 Oct 2008
Posts: 113
Location: Germany

Post Reply with quote
the same for me, if it is what it seems to be, then every approach to break the code failed so far.
Wed Jan 28, 2009 9:17 am View user's profile Send private message
gfoot



Joined: 05 Sep 2007
Posts: 269
Location: Brighton, UK

Post Reply with quote
It is hard, much harder than I thought. I wrote an analysis tool to see exactly how hard it was going to be, but it looks like I underestimated. The key is to look at relationships rather than individual values.

adum asked me to post an easier example, but I forgot - I'll send it soon though. It might help you work out how your analysis should work.
Thu Jan 29, 2009 1:49 pm View user's profile Send private message
MagneticMonopole



Joined: 07 Nov 2008
Posts: 26

Post Can no longer access challenge Reply with quote
Well, I solved the challenge some days ago (and answered the question correctly). Now the challenge is gone, at least from my perspective. Accessing the challenge url directly tells my that I am not ready for this challenge. What happened?
Sat Feb 14, 2009 12:22 am View user's profile Send private message
gfoot



Joined: 05 Sep 2007
Posts: 269
Location: Brighton, UK

Post Reply with quote
There's a warm-up challenge before it now, which you need to solve before the other will appear again.
Sat Feb 14, 2009 1:12 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
Well I decrypted it but I can't answer the question! The number 43 is not used in the text - is that spoiling my key input?

EDIT - got it, see the rest of this post for a clue! Smile

_________________
There is no spoon.
Mon Mar 08, 2010 7:43 pm View user's profile Send private message
Hippo



Joined: 01 Feb 2014
Posts: 332
Location: Praha 5

Post Reply with quote
What form should the answer have? Is it like in warmup?
Or there should be english text after deciphering?

Thanks
Mon Apr 07, 2014 10:03 am View user's profile Send private message
Hippo



Joined: 01 Feb 2014
Posts: 332
Location: Praha 5

Post Reply with quote
Damn, I have hoped there is thread for solvers there ...

[edit] ... moved there [/edit]


Last edited by Hippo on Tue Apr 12, 2016 11:59 pm; edited 1 time in total
Sun Apr 10, 2016 8:48 pm View user's profile Send private message
eulerscheZahl



Joined: 29 Nov 2012
Posts: 55
Location: Germany

Post Reply with quote
I only searched for different numbers, that represent the same letter with my code (by calculating some kind of square difference).
Then it was only a matter of guessing and frequency analysis. [sentence removed]

And I have no idea, what you did here Shocked


Last edited by eulerscheZahl on Mon Apr 11, 2016 2:46 pm; edited 1 time in total
Mon Apr 11, 2016 4:59 am View user's profile Send private message
Hippo



Joined: 01 Feb 2014
Posts: 332
Location: Praha 5

Post Reply with quote
Hmmm I have not spoiled the question of presented alphabet ...

The beam search is basically maintaining the best "window" solutions according to evaluation of partially filled plaintext (corresponding to partial keys). Only keys in the window are extended for the next generation. ... So you should have evaluator of partial plain texts "language model".
Good ordering of where to extend the keys helps. (For example first cipher letter 01, next cipher letter 07 ...)

You hope to have language model which evaluates best the plain text corresponding to original plain text.
And you hope all the generations of partial plaintexts corresponding to the key extesions would fit to the corresponding window.


Last edited by Hippo on Wed Apr 13, 2016 12:00 am; edited 1 time in total
Mon Apr 11, 2016 12:19 pm View user's profile Send private message
Hippo



Joined: 01 Feb 2014
Posts: 332
Location: Praha 5

Post Reply with quote
Moved to solved section ...


Last edited by Hippo on Wed Apr 13, 2016 12:02 am; edited 2 times in total
Tue Apr 12, 2016 9:37 pm View user's profile Send private message
AMindForeverVoyaging
Forum Admin


Joined: 28 May 2011
Posts: 472
Location: Germany

Post Reply with quote
Hippo wrote:
Damn, I have hoped there is thread for solvers there ...


There are threads for both challenges in the "Challenges Solved" section.

Sounds Same Warmup: http://www.hacker.org/forum/viewtopic.php?t=1280
All Sound Same: http://www.hacker.org/forum/viewtopic.php?t=1261
Tue Apr 12, 2016 10:05 pm View user's profile Send private message
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