"Eleven days ago, the nonprofit entity that develops the protocol, Signal Messenger LLC, published a 5,900-word write-up describing its latest updates that bring Signal a significant step toward being fully quantum-resistant," writes Ars Technica:
The mechanism that has made this constant key evolution possible over the past decade is what protocol developers call a "double ratchet." Just as a traditional ratchet allows a gear to rotate in one direction but not in the other, the Signal ratchets allow messaging parties to create new keys based on a combination of preceding and newly agreed-upon secrets. The ratchets work in a single direction, the sending and receiving of future messages. Even if an adversary compromises a newly created secret, messages encrypted using older secrets can't be decrypted... [Signal developers describe a "ping-pong" behavior as parties take turns replacing ratchet key pairs one at a time.] Even though the ping-ponging keys are vulnerable to future quantum attacks, they are broadly believed to be secure against today's attacks from classical computers. ...
[ Read it >> ]
0 Replies