Date of Award


Document Type

Thesis (Master's)

Department or Program

Department of Computer Science

First Advisor

Sean Smith


Message authentication with low latency is necessary to ensure secure operations in legacy industrial control networks, such as power grid networks. Previous authentication solutions by our lab and others looked at single messages and incurred noticeable latency. To reduce this latency, we develop Predictive YASIR, a bump-in-the-wire device that looks at broader patterns of messages. The device (1) predicts the incoming plaintext based on previous observations; (2) compresses, encrypts, and authenticates data online; and (3) pre-sends a part of ciphertext before receiving the whole plaintext. I demonstrate the performance properties of this approach by implementing it in the Scalable Simulation Framework and testing it on Modbus/ASCII protocol, which is widely used in the power grid, oil and gas, manufacturing, and water treatment control networks. By looking at broader message patterns and using predictive analysis, my results demonstrate a 15.48 +/- 0.35% improvement in latency over the previous most efficient solution. The simulation code is available from


Originally posted in the Dartmouth College Computer Science Technical Report Series, number TR2010-665.