Talking in code...

[mathcam]

Aside from the possible ethical questions, I don't see how people can claim that cryptrgaphy is usually bad. If it's used correctly (i.e. indecipherably), it can be an incredible boon to the town. As has been mentioned before, any time a player has information that is dangerous to reveal immediately but certainly needs to revealed

eventually

is a good candidate for encryption. Say I'm a role-name investigator and I figure myself to be a huge target if I come out, and I have some questionable (though not certainly evil) characters in the game. I can transmit this information to any player whose role name is definitely innocent by using the character's role name as the decryption key, by posting the encrypted message in the thread. Now that player has the information and use his/her discretion whether or not to reveal even after I die, and even better, it is unknown which player has that information. Keeping in mind that all my arguments are "in theory only", I should also point out that if this were to be a technique of yours, you should also occasionally do it when you have no information at all. This is so that the fact that you are encrypting something does not automatically give away that you have an information-gathering role.

There is absoultely no doubt in my mind that cryptography can be a tremendous boon to the town in many different scenarios.

Cam

[mathcam]

Only if the decryption is not trivial.

Agreed.

And you need some way to pass the key to only the correct person.

True, but often this is built in to the system. For example, in the role-investigator scenario, the investigator and the investigee already share a private key...the role name known to both players. There's no need in this scenario even for a key exchange. And like Norinel mentions, achieving a correct transfer is also quite easy (in theory).

And that person needs to be technically sopisticated enough to decipher the code.

Also true, but this basically reduces to being technically sophistacated enough to click on a hyperlink and paste in a large number.

There are still essentially unbreakable public key systems, right?

Yup, though the word "essentially" does require emphasis. First, any current cryptosystem (other than quantum cryptography) is susceptible to brute force given sufficient time and computing power. Second, no cryptosystem to date is proven to be unbreakable by some technique shorter than brute force. It's

possible

(though certainly unlikely) that RSA is easy to crack. But in short, "yes."

Cam

[mathcam]

Matcam -- one time pads, if not reused, have been proven to be unbreakable. Nature of the beast.

Okay, fair enough, but this isn't really a cryptographic protocol. It, in turn, has its own drawbacks, as Norinel points out.

Cam

[mathcam]

How about the box with two locks approach...

I have a message I want to send to mathcam (for example) so I use my procedure to encode it... I then display it in my post... mathcam then takes the encoded text and encodes it using his own procedure. He then displays the result. I then decode his result and post the message a 2nd time...
All mathcam needs to do now is decode the message one last time and he has the original text...

Depending on how you choose to "encode" in this example, this is called the Diffie-Hellman key exchange, used prominently both with RSA and with Elliptic Curve Cryptography. This is a decent protocol, but it hinges on the difficulty of cracking the encoding. If I can brute force the cracking of your encryption, then it doesn't matter how fancy of a protocol you use.

Cam

[mathcam]

It does indeed necessitate commutativity, at least at first glance. There are non-commutative encryptions, but as you point out, these would need fancier protocols.

Cam

[mathcam]

Hmm. I'm not sure if I'm being mocked or not.

Cam

[mathcam]

Oh, now I get it. Some times...

Cam

[mathcam]

It's fairly clearly (though admittedly indirectly) modquoting, which is prohibited (and, as DP points out, punishable by modkill) in almost all games on the site.

Cam