Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
17 Cards in this Set
- Front
- Back
- 3rd side (hint)
|
Authentication Protocols
|
Type of protocol with the purpose of authenticating entities wishing to communicate securely.
|
|
|
|
Key Exchange protocols
|
Two or more parties agree on a key - can also be vouched by a third party which makes it even more trustworthy. Also used passwords, shared secret keys, and public/private key pairs to prevent attacks
|
|
|
|
Aliveness
|
If A(as initiator) completes a run of the protocol, apparently with responder B, then B was previously running the protocol.
|
|
|
|
Weak Agreement
|
if A (as iniator) completes a run of the protocol, apparently with B, then B was previously running the protocol, apparently with A
|
|
|
|
Non-Injective Agreement
|
Same as Weak except B was acting as responder in this run, and, A and B agreed on the values corresponding to all the variables in ds
|
|
|
|
Agreement
|
Same as Non-Injective Agreement except Each such run corresponds to a unique run of B
|
|
|
|
Session/Run/Rounf
|
A sequence of messages between principles that constitute the beginning to the end of the protocol.
|
|
|
|
Principles
|
Alice (A) and Bob (B) are Principles
|
Mike (M) is the adversary
|
|
|
Nonces
|
A random number N only used one (Np a nonce generated by A)
|
|
|
|
Challenge Response
|
A message is sent (the "challenge") which leads to a reply (the response) which could only have been produced with knoweldge of the challenge
|
|
|
|
Challenge Response Attack
|
A and B share a key Kab, A wishes to authenticate B and with the N she things she's talking to bob but Mike could be in the middle interfering
|
|
|
|
Freshness
|
The freshness of messages must be inferred from some component of the message. To work it must be bound with the rest of the message. Encryption is NOT the way to do that. Put it in T stoamp and c stamp? Slide 15
|
|
|
|
Type Flaw Attacks
|
An attack where a field that was originally intended to have one type is subsequently interpreted as having another type.
|
Can bfix this by tagging fields with extra information to indicate the intended type. For example some bits attached to the field, maybe with different bit patterns for different types.
|
|
|
Freshness Attacks
|
If an old key Kab is compromised how can you tell it's a recent key?
|
Message from a previous run of a protocol is replayed as a message in the current run
|
|
|
Parallel Session Attacks
|
Parallel execution of multiple protocols, intruder uses messages from one session to synthesise messages in the other session.
|
Alice acts as the oracle that provides the right answer for round 1 and M initates round 2. uses principle as an oracle for appropriate answers.
|
|
|
Fix to Parallel Session Attacks
|
watch out for them?
|
|
|
|
Replay Attack
|
Without freshness identifiers an adversary can get himself authentication by replaying messages copied from a legitmate session
|
|
