## Building a cipher for a friend.

The fear of every surveillance society: citizens protecting their own privacy with strong cryptography

### Building a cipher for a friend.

I wanted to give my friend a little bit of a challenge. I'm solving it in reverse before I give it to them (to make sure it's not too hard) and I am asking for your help.

It's a simple substitution cipher, where each pair of letters represents a single letter; EX: DG = Z (it doesn't btw). It's pretty much a ADFGVX cipher without the keyword. Can you solve it? If you do, can you tell me what you did?

DG VG AF XV VA XA VG AF DG FD XV FG VA VG GX VA VG AF
NightStalker111
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### Re: Building a cipher for a friend.

I can get almost everything but cant figure out what the XV is...clue maybe?
Im off, last year of school and all, I had something longer but char limit fucked that up. So yeah, had a good run here. Thanks for the memories. Thanks to the staff and users.

Best regards, your posting whore,
godofcereal

p.s. Defience, you the man ;)

godofcereal

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### Re: Building a cipher for a friend.

I could tell you if you'd like. But since you asked for a clue, I'll give it to you.

"Almost always that, but sometimes this"
NightStalker111
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### Re: Building a cipher for a friend.

I think I get it. The answer is random letters right? If it isnt Iv gone wrong.
Im off, last year of school and all, I had something longer but char limit fucked that up. So yeah, had a good run here. Thanks for the memories. Thanks to the staff and users.

Best regards, your posting whore,
godofcereal

p.s. Defience, you the man ;)

godofcereal

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### Re: Building a cipher for a friend.

godofcereal wrote:I think I get it. The answer is random letters right? If it isnt Iv gone wrong.

No, if random letters were encrypted, the ciphertext would be readable

Seriously though, I have made no headway at all. The message is too short for frequency analysis and without the actual word spacing its beyond my limited ability to crack.
"To understand recursion you must first understand recursion."
aNewHobby4me
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### Re: Building a cipher for a friend.

That's the problem I've been running into. The original ADFGVX cipher was cracked with very extensive effort and it only could be cracked during times of high traffic. Without knowing somewhat what the message is supposed to say, it's nigh impossible to come up with a reliable/accurate plaintext. At least without a computer.

To top it off, this is only half of the cipher. The second step is to transposition the cipher text to further encrypt the message.

I guess I'll have to move to an easier encryption technique. Or perhaps I'll have to add in some clues. Thanks for trying though fellas, I really appreciate the help.

If you guys want me to post the answer, just tell me. Or I can pm it if you want.
NightStalker111
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Posts: 7
Joined: Sat Mar 28, 2009 9:20 pm
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### Re: Building a cipher for a friend.

Id like to compare my answer to the correct one.
If Im close or correct Il post what I think about it.
Im off, last year of school and all, I had something longer but char limit fucked that up. So yeah, had a good run here. Thanks for the memories. Thanks to the staff and users.

Best regards, your posting whore,
godofcereal

p.s. Defience, you the man ;)

godofcereal