Richard Schroeppel

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The Diffie-Hellman key exchange algorithm can be implemented using the group of points on an elliptic curve over the field F2n . A software version of this using n = 155 can be optimized to achieve computation rates that are significantly faster than non-elliptic curve versions with a similar level of security. The fast computation of reciprocals in F2n is(More)
We show that there is a very straightforward closed algebraic formula for the Rijndael block cipher. This formula is highly structured and far simpler then algebraic formulations of any other block cipher we know. The security of Rijndael depends on a new and untested hardness assumption: it is computationally infeasible to solve equations of this type. The(More)
Several related algorithms are presented for computing logarithms in fieldsGF(p),p a prime. Heuristic arguments predict a running time of exp((1+o(1)) $$\sqrt {\log p \log \log p} $$ ) for the initial precomputation phase that is needed for eachp, and much shorter running times for computing individual logarithms once the precomputation is done. The running(More)
With the increasing growth of electronic communications, it is becoming important to provide a mechanism for enforcing various security policies on network communications. This paper discusses our implementation of several previously proposed protocols that enforce the Bell LaPadula security model. We also introduce a new protocol called \Quantized Pump"(More)
We describe a new method for authenticated encryption, which uses information from the internal state of the cipher to provide the authentication. This methodology has a number of benefits. The encryption has properties similar to CBC mode, yet the encipherment and authentication mechanisms can be parallelized and/or pipelined. The authentication overhead(More)
Software subsystems that implement cryptographic security features can be built from small modules using uniform interfaces. The methods demonstrated in this paper illustrate how configuration flexibility can be achieved and how complex services can be constructed, all using the same building block modules. These allow the configuration process to be(More)