12. Cryptographic Protocols Flashcards
What are cryptographic protocols?
Programs relying on cryptographic primitives with the goal of establishing secure communications
Why do we want to avoid public key algorithms unless necessary?
Computational more expensive
Why do we use long term keys as little as possible?
Reduce attack surface, reusing keys gives more information to the attacker
What is a nonce?
Arbitrary random number that is used just once in cryptographic communication
How does NSPK work?
A is an acknowledment message
What does NSPK stand for?
Needham-Schroeder Public Key
What is Lowe’s fix for NSPK?
What is the advantage of StS over NSPK (with fix)?
StS ensures forward secrecy
What does StS stand for?
Station to station
What is forward secrecy?
if long-term keys are comprimised, past sessions are kept confidential, even if an attacked activly interferred
What is anonymity?
Use may use a resource/service without disclosing their identity
What is unlinkablility?
User may make multiple uses of a resource/service without other users linking them together
