TARDIS Implementing Secure Protocols on Embedded Devices without - PowerPoint PPT Presentation

TARDIS Implementing Secure Protocols on Embedded Devices without Clocks Amir Rahmati , Mastooreh Salajegheh, Dan Holcomb 1 , Jacob Sorber 2 , Wayne Burleson, Kevin Fu 1 UC Berkeley 2 Dartmouth Collage

The Problem Slow Brute Force attacks on batteryless devices E-Passports Smartcards Garcia et al., Oakland’09 Kasper et al., ISSE’11 Amir Rahmati - TARDIS

Clocks Need Power No Notion of Time 1 Second? 1 Year? Q Q Q Q Q Q No knowledge about the Q Q Q query rate Q Q Q Q Q Q Amir Rahmati - TARDIS

Our Solution Use decay in SRAM to derive a notion of time 1 1 1 1 1 x x x x x 1 1 0 1 0 Halderman et al., Cold boot Gutmann, Secure deletion, attacks, USENIX Sec’08 USENIX Sec’96 Amir Rahmati - TARDIS

How it works Three Stages of Decay Query Refused Query Accepted t1 t2 TARDIS gives TARDIS TARDIS gives 1 bit of info estimates 1 bit of info 50 time Factors affecting stage lengths: % Memory Decay Stage 1 Stage 2 Stage 3 Circuit specifications • Capacitance • Temperature • Stages can range from seconds to hours 0 Time Without Power What about a thermal attacks? Amir Rahmati - TARDIS

TARDIS: Time And Remanence Decay In SRAM time Materializing in USENIX Security 2012 https://spqr.cs.umass.edu/tardis/ Holcomb RFID Sec’07, IEEE Trans’09