Sunday, December 09, 2007

Random thuds on cracking public key encryption

Lemme see now...

Let T be a plaintext which Alice must convey to Bob.

Let ¤ represent exclusive-or, or some similar operation which is reversible when twice applied (or at least symmetric, like TEA, where encode and decode work jes' fine.)

Let P be Alice's public key, and p be her private key.

Let PM¤p, where M is mysterious.

Let Q be Bob's public key, and q his private key.

Let QM¤q, where M is still mysterious.

Alice cleverly enciphers CT¤Q¤p.

Alice pops C into an envelope and sends it to Bob, awaiting anxiously.

Bob deduces Alice's private key, p ← (M¤p)¤(M¤qqP¤Q¤q.

Bob deciphers TC¤Q¤p.


Ok. This probably ain't how public key encryption works, but if it reduces to this case, kiddies, the jig is up!

M is not my favorite pseudorandom number generator, Mersenne Twister. M is mysterious! Like this.



Post a Comment

Subscribe to Post Comments [Atom]

<< Home