No it bloody doesn't.

[ciphergoth]

Mathematicians who know fuck all about crypto are fond of saying that their latest discovery might have crypto applications.

http://news.bbc.co.uk/1/hi/sci/tech/2146295.stm

In this case, as usual, it doesn't.

Why is it crypto, of all fields, that attracts this idea that you don't have to know a damn thing about it to innovate in it? All fields get crackpots, but even crackpots have a vision that there are people employed to do some research in this field already, whereas there seem to be an endless supply of people who act as if they are the first to think really hard about encryption.

Update: Whoops, I spoke too soon. It turns out that Carl Pomerance among others is involved in this research, so I guess it is legit. I'm surprised.

Comments

Lay guess

[pavlos.livejournal.com]

I guess the answer goes like this: Let's say the cryptosystem involves choosing a normal number, like the root of a large prime, as key and xoring the plaintext with its bits. Then, if I assume the input contains a large block of zeros, which it often does, how easily can I determine the key from an arbitrary sequence of its bits?

Pavlos

Re: Lay guess

[babysimon]

That approach (which I'm sure Paul can remind us of the technical name for) has another defect - you can never use the same key twice! If the key is X, and the messages are A and B, your attacker has X xor A and X xor B.

(X xor A) xor (X xor B) = X xor A xor X xor B = X xor X xor A xor B = A xor B.

A xor B is usually pretty easy to decipher with a little guesswork.

Re: Lay guess

[ciphergoth.livejournal.com]

Vernam cipher. This isn't really a defect - you should never use the same (key, nonce) pair twice with any stream cipher. CTR and OFB modes turn a block cipher into a Vernam stream cipher, and they're perfectly secure if the block cipher is secure.

Re: Lay guess

[babysimon]

Yeah, but I have to flaunt the tiny bits of crypto that I do know.