Presentation on theme: "PSKA: Usable and Secure Key Agreement Scheme for Body Area Networks Authors: Krishna K. Venkatasubramanian, Ayan Banerjee, Sandeep K.S. Gupta Presenter:Francis."— Presentation transcript:
PSKA: Usable and Secure Key Agreement Scheme for Body Area Networks Authors: Krishna K. Venkatasubramanian, Ayan Banerjee, Sandeep K.S. Gupta Presenter:Francis Usher
Problem Domain: Body Area Networks (BANs) Sensors in BANs collect and disseminate sensitive health Security via cryptography requires key distribution
Cryptography (overview) Problem of sharing data securely Symmetric-key cryptography – Secret key k is used to obscure message m into cyphertext c – Given c, only k can be used to reveal m Advantage: provable that adversary can only break cryptosystem with negligible probability Problem: how do we communicate keys?
IPI-based key generation Synchronized sensors measure IPI (EKG/PPG) Encode measurements as key 4 observations: – Meets randomness goal, however: – High-latency – Two keys generated tend to differ in half of bits – This distance tends not to vary much in time between generation or across different patients – No good tradeoff threshold between false positive/negative rates
PSKA: Sharing keys using fuzzy vaults Different sensors measure phys. signals – “Loosely synchronized” Transform signals to create “features” Generate random polynomial representing key Map features under polynomial Obscure feature maps using “chaff” points Only similar feature set can infer polynomial from vault (features + chaff) Use MACs to affirm that key was shared correctly
Possible attacks Fuzzy vault attacks – Some based on application to biometrics – One attack based on vault-construction artifact Early points (features) have more “free area” Dismissed but not thoroughly argued against
Idea for future work Use fuzzy vaults to communicate public keys – Use asymmetric crypto handshakes to establish session keys – Frequent update of public keys – Eliminates problem of contacting trusted authority since physiological signals good for authentication of body-area presence