Forward-Security in Private-Key Cryptography

Authors: M. Bellare and B. Yee

Abstract: This paper provides a comprehensive treatment of forward-security in the context of shared-key based cryptographic primitives, as a practical means to mitigate the damage caused by key-exposure. We provide definitions of security, practical proven-secure constructions, and applications for the main primitives in this area. We identify forward-secure pseudorandom bit generators as the central primitive, providing several constructions and then showing how forward-secure message authentication schemes and symmetric encryption schemes can be built based on standard schemes for these problems coupled with forward-secure pseudorandom bit generators. We then apply forward-secure message authentication schemes to the problem of maintaining secure access logs in the presence of break-ins.

Ref: Extended abstract in Topics in Cryptology - CT-RSA 03, Lecture Notes in Computer Science Vol. 2612, M. Joye ed, Springer-Verlag, 2003. Full paper available below.

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