Controlled operations as a cryptographic primitive

Abstract

Controlled two-place operations (CTPO) are introduced as a new cryptographic primitive for the block ciphers. Design criteria, structure, some good cryptographic properties of the CTPO are considered. There are proposed CTPO representing single nonlinear operations on the operands of relatively large length. It is shown that CTPO in combination with the controlled permutations (CP) can be efficiently used to construct fast block ciphers. Three different cryptoschemes based on data-dependent two-place operations and data-dependent permutations are presented. A feature of the cryptoschemes is the use of the CTPO and CP for construction of some mechanisms of the internal key scheduling which consists in data-dependent transformation of the round keys.