2015 cipher challenge

[Jarlve]

Hello everyone,

A cipher challenge fit to a scheme and rules sound like a great idea to me. The main objective is to become smarter about the specific scheme, to learn and possibly develop new systems to expose weaknesses, that in turn could have a carry over to the 340.

Let's say the schemes are "transposition, homophonic substitution" and the rules are:

- 340 symbols in a 17x20 grid, 63 unique symbols.
- These schemes must be used only, no double encyption etc.
- Plaintext is of english language, lower case, and read from left-to-right, top-to-bottom before transposition.
- Plaintext must be recoverable with ZKDecrypto after undoing the transposition scheme.
- Plaintext must be unrecoverable with ZKDecrypto before undoing the transposition scheme.
- Make a note when your cipher needs other than standard ZKDecrypto settings to be solved, for example IOC: 3.
- Transposition may be done before and/or after the homophonic substitution.
- The transposition scheme must follow a certain logic, obviously transpositioning all 340 symbols to random positions is unrecoverable.
- You may not give tips and hints, the cipher stands until it is broken.
- You may only submit one cipher at a time, and may submit a new one if your current one is solved.
- You do not have to mimic strange behaviour seen in the Zodiac 340.
- You do not try to play around the rules somehow.
- You do not use a plaintext from my library, or an existing plaintext of any cipher that you are aware of.
- Preferably you create an easy cipher to start with and then make a more difficult one after it is solved.
- You give a rating as how hard you think your cipher is: EASY, MEDIUM, HARD.
- Multiple transposition may be layered but be sure to rate the difficulty of your cipher accordingly.

I'd like to know who would be interested, in creating such a cipher and/or trying to solve these.

Here is a homophonic substitution generator: http://code.google.com/p/zkdecrypto/downloads/list

[glurk]

Give me about 20 or 30 minutes and I will create one of these for you.

-glurk

EDIT: Here is my "challenge" and I would have to call it easy. It is a text of my own writing, with a simple transposition, and homophonically encoded.

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[Jarlve]

Thanks for your entry glurk!

Here is my entry. Not sure about the difficulty, probably easy to medium.

16AO-1=+Y<T=&P>HT
(yVG<=@vlZ>^T6Z1{
,\H<%F^%<G>0<O/w}
J.O@Y?S5DGJ\;BB44
FO=FY<G_&&ZI]{lo\
}OTf>hMJ--BD&+JHw
'HVZ,I,n1}~ZCYVKQ
nO'YT?H'(M%f>4ARS
h1IQIwZw^.}J=S,?y
Nh*-QKSP+%%F5\GQv
P~"Dw45BkOhJIRH_B
6B<h?f'}~0(M1,+AZ
K@_.VG"6]Ek<5E-C<
O"YNQv0RPnZ}f*K0A
{yvY6A%"~]yRC"A,E
0I@,5,^N.f@j+<,RN
5S_4VBM=_M",6HGl'
'O)n<yv_R-,kBVDw+
TB>H?%FO\y,w6VEDY
T4EkC5KD0I~f"QWJB

[_pi]

Good idea!

glurk's is gibberish...

_pi

[Jarlve]

_pi, would you like to create a cipher to these rules?

[glurk]

Jarlve has asked me to create another one of these, so I have done so. I was going for "medium" difficulty on this one, but it might be more like "easy."
I could make it much harder, but I don't think doing that would be much help. In any case, I have no problem with making these, it's pretty simple.
A PM or message from anyone who solves it would be appreciated. As per "the rules" I am giving no hints or anything.

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NOTE: I like to post these as numeric ciphers, because message boards can mess up ASCII text sometimes.

[glurk]

A challenge cipher has been posted on Tom Voigt's board here:

http://zodiackiller.fr.yuku.com/topic/7 ... -Challenge

The OP says "I don't know if this will be easy or hard. May take 2 hours, 2 days, 2 weeks?"
He is apparently unaware of the programs that are out there.

-glurk

[traveller1st]

A challenge cipher has been posted on Tom Voigt's board here:

http://zodiackiller.fr.yuku.com/topic/7 ... -Challenge

The OP says "I don't know if this will be easy or hard. May take 2 hours, 2 days, 2 weeks?"
He is apparently unaware of the programs that are out there.

-glurk

Done. AFAICT

Took about 5 or 6 mins. That's no achievement on my part though. I had some 'eople' help?.

Note to members - SAME RULES - Please don't post the results here either. That wouldn't be fair or nice.

[glurk]

Trav-

I agree 100%, the OP asked that no one reveal the solution, and there is no point in doing so here.

That said, creating a homophonic cipher of this type is NEVER an easy task, and I'd happily welcome him to join here. But I want the board to be swimming with cryptographers. It's like swimming with sharks, but safer.

-glurk

[traveller1st]

It's like swimming with sharks, but safer.

-glurk

Hmmmmm. IYO ...

and if you have the right equipment to handle them and if the water hasn't been chummed.