X-Git-Url: https://git.distorted.org.uk/u/mdw/catacomb/blobdiff_plain/35682d2fa436ace2d7706fd6dcd852b497079860..298182ad446aaced14dea7ed0e7c968946787288:/square-mktab.c diff --git a/square-mktab.c b/square-mktab.c index 5c2610e..ba2c539 100644 --- a/square-mktab.c +++ b/square-mktab.c @@ -1,6 +1,6 @@ /* -*-c-*- * - * $Id: square-mktab.c,v 1.1 2000/07/27 18:10:27 mdw Exp $ + * $Id: square-mktab.c,v 1.3 2004/04/08 01:36:15 mdw Exp $ * * Build precomputed tables for the Square block cipher * @@ -27,14 +27,6 @@ * MA 02111-1307, USA. */ -/*----- Revision history --------------------------------------------------* - * - * $Log: square-mktab.c,v $ - * Revision 1.1 2000/07/27 18:10:27 mdw - * Build precomuted tables for Square. - * - */ - /*----- Header files ------------------------------------------------------*/ #include @@ -84,9 +76,9 @@ static unsigned mul(unsigned x, unsigned y, unsigned m) * Build the S-box. * * This is built from inversion in the multiplicative group of - * %$\gf{2^8}[x]/(p(x))$%, where %$p(x) = x^8 + x^4 + x^3 + x + 1$%, followed - * by an affine transformation treating inputs as vectors over %$\gf{2}$%. - * The result is a horrible function. + * %$\gf{2^8}[x]/(p(x))$%, where %$p(x) = x^8+x^7+x^6+x^5+x^4+x^2+1$%, + * followed by an affine transformation treating inputs as vectors over + * %$\gf{2}$%. The result is a horrible function. * * The inversion is done slightly sneakily, by building log and antilog * tables. Let %$a$% be an element of the finite field. If the inverse of