Non-expanding, key-minimal, robustly-perfect, linear and bilinear ciphers

Abstract

The purposes of this paper are: (1) to give appropriate definitions of robustly-perfect ciphers, linear ciphers and bilinear ciphers: (2) to give two general constructions of robustly-perfect bilinear block ciphers that do not expand the plaintext and that have the smallest possible amount of secret key; (3) to give some isolated examples of robustly-perfect linear stream ciphers that use less key than had been earlier conjectured to be necessary; and (4) to suggest some possible useful applications for robustly-perfect linear and bilinear ciphers.