TLS Flashcards
High level goals of TLS
entity authentication, integrity, confidentiality
Secondary goals of TLS
Efficiency, flexbility, self-negotiation, protection of negotiation
When is it best to rekey
After 2^(24.5) records
How did TLS facilitate 1-RTT
Feature reduction, it always does ECDHE in a shortlist of groups
What were the goals of TLS 1.3?
Clean up, improve latency, improve privacy (hide as much as possible from the handshake), continuity, security assurance
How does TLS protect against replay attacks?
Per record seq number
How does TLS1.3 provide confodentiality and integrity
Encryption and MAC via AEAD scheme.
Does TLS 1.3 prevent reflection attacks?
Yes, there is key seperation
List the 5 ciphers in TLS 1.3
AES 128 GCM 256 GCM 128 CCM 256 CCM ChachaPoly130.. All with sha256, except 256Gcm with sha384
What are possible attacks on TLS 1.3
Application layer confusion: record end is not APDU end
Truncation attack
Timing attacks on padding scheme
TLS PROTOCOL
How can attacker snoop on all traffic in TLS 1.3
If cliwnt uses predictable PRNG, can predict private DH values and snoop.
How can you encrypt the client hello in TLS 1.3
Provide a public cert using DNS.
Is a Nonce leak bad in TLS?
As long as the nonce is not reused with the same key, it is fine. Keys are newly generated, so should not happen.
