%T YASIR: A Low-Latency, High-Integrity Security Retrofit for Legacy SCADA Systems %A Patrick P. Tsang %A Sean W. Smith %R Technical Report TR2007-603 %I Dartmouth College, Computer Science %C Hanover, NH %D September 2007 %U http://www.cs.dartmouth.edu/reports/TR2007-603.pdf %X We construct a bump-in-the-wire (BITW) solution that retrofits security into time-critical communications over bandwidth-limited serial links between devices in Supervisory Control And Data Acquisition (SCADA) systems. Previous BITW solutions fail to provide the necessary security within timing constraints; the previous solution that does provide the necessary security is not BITW. At a comparable hardware cost, our BITW solution provides sufficient security, and yet incurs minimal end-to-end communication latency. A microcontroller prototype of our solution is under development. %Z Updated as TR2008-617. You can find it here.