A new public-key cryptosystem family based on feedback shift registers

Nearly all public-key cryptographic algorithms are based on hard problems of number theory, which are related to each other. That is to say, if one of these algorithms is broken, the other´s security will be threatened. This work presents a new public-key ciphering mechanism that isn´t based on any of the classic cryptographical problems. The method consists of permuting the elements of the field GF(2^L). The permutation is constructed by composition of bijective transitions based on the feedback functions of the feedback shift registers. The permutation algorithm is transmitted as a nonlinear equation system, where the difficulty of solving it conveys the security of the cipher. At the implementation level, the proposed scheme makes use of NLFSR (non-linear feedback shift registers), modifying the feedback function at each iteration. The resulting ciphering mechanism is able to generate any permutation