Papers     Last modified: 08/27/03 11:56:54 AM

S.W. Smith, J.D. Tygar.
``Security and Privacy for Partial Order Time.''
ISCA Seventh International Conference on Parallel and Distributed Computing Systems.
October 1994.


Partial order time expresses issues central to many problems in asynchronous distributed systems, but suffers from inherent security and privacy risks. Secure partial order clocks provide a general method to develop application protocols that transparently protect against these risks. Our previous Signed Vector Timestamp [32] protocol provided a partial order time service with some security: no one could forge dependence on an honest process. However, that protocol still permitted some forgery of dependence, permitted all denial of precedence, and leaked private information. This paper uses secure coprocessors to improve the vector protocol: our new Sealed Vector Timestamp protocol detects both the presence and absence of precedence even in the presence of malicious processes, and protects against some privacy risks as well. Our new protocol solves previously open security problems, and provides a foundation for incorporating security and privacy into distributed application protocols based on partial order time.



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