# On Selection of Optimal Parameters for the WG Stream Cipher Family

### Abstract

In this paper, we first present some new results about the Welch-Gong (WG) transformations, followed by a description of the WG stream cipher family which is built upon an LFSR and a WG transformation over an extension field. The randomness properties of keystreams produced by a decimated WG cipher are derived based on the new results. We also discuss the selection criteria for choosing the optimal parameters for a WG cipher in order to achieve the maximum level of security. Finally, we present the optimal parameters for the WG transformations over $F_{2^m} , 7 \leq m \leq 16$ based on the proposed criteria.

Publication
The 13th Canadian Workshop on Information Theory (CWIT 2013)