Security of TLS ≤1.2 The ACCE model TLS Crypto Seminar February 7, 2019 Joseph Jaeger UC San Diego some slides & formatting stolen from Felix Günther February 7, 2019 | Security of TLS | TLS Crypto Seminar, Winter 2019 Quarter, UC Joseph Jaeger 1 San Diego
Today's Plan Goal ● What is the ACCE security model? Why was it needed for studying TLS? ● Dig into the details of the formalism. Part I Background ● Stateful Length-Hiding Authenticated Encryption ● Authenticated Key Exchange Part II ACCE Security Model ● Authenticated and Confidential Channel Establishment ● TLS 1.2 Security Results (Time Permitting) February 7, 2019 | Security of TLS | TLS Crypto Seminar, Winter 2019 Quarter, UC Joseph Jaeger 2 San Diego
Background February 7, 2019 | Security of TLS | TLS Crypto Seminar, Winter 2019 Quarter, UC Joseph Jaeger 3 San Diego
TLS Components From the first lecture: Security Typically Desired: ● Handshake Protocol = Authenticated Key Exchange ● Record Protocol = Stateful Length Hiding Authenticated Encryption February 7, 2019 | Security of TLS | TLS Crypto Seminar, Winter 2019 Quarter, UC Joseph Jaeger 4 San Diego
Formalisms Formalisms based on: February 7, 2019 | Security of TLS | TLS Crypto Seminar, Winter 2019 Quarter, UC Joseph Jaeger 5 San Diego
sLHAE Definition Syntax February 7, 2019 | Security of TLS | TLS Crypto Seminar, Winter 2019 Quarter, UC Joseph Jaeger 6 San Diego
sLHAE Definition Security Security Typically Desired: ● All-in-one definition requiring left-right IND-CPA and INT-CTXT style security February 7, 2019 | Security of TLS | TLS Crypto Seminar, Winter 2019 Quarter, UC Joseph Jaeger 7 San Diego
Key Exchange Definition Previously February 7, 2019 | Security of TLS | TLS Crypto Seminar, Winter 2019 Quarter, UC Joseph Jaeger 8 San Diego
TLS Example February 7, 2019 | Security of TLS | TLS Crypto Seminar, Winter 2019 Quarter, UC Joseph Jaeger 9 San Diego
ACCE February 7, 2019 | Security of TLS | TLS Crypto Seminar, Winter 2019 Quarter, UC Joseph Jaeger 10 San Diego
ACCE Main Idea: Squish encryption and key exchange security together into single notion. February 7, 2019 | Security of TLS | TLS Crypto Seminar, Winter 2019 Quarter, UC Joseph Jaeger 11 San Diego
Results Main Result: TLS-DHE is secure in this model February 7, 2019 | Security of TLS | TLS Crypto Seminar, Winter 2019 Quarter, UC Joseph Jaeger 12 San Diego
Results Model: Closely related to discussed ACCE model. No client authentication. No forward security. Main Result: TLS-RSA is secure in this model. (Under OW-PCA assumption.) TLS-DH is secure in this model. (Under PRF-ODH assumption.) TLS would be secure in this model with CCA secure encryption February 7, 2019 | Security of TLS | TLS Crypto Seminar, Winter 2019 Quarter, UC Joseph Jaeger 13 San Diego
Recommend
More recommend