X-Git-Url: https://git.distorted.org.uk/u/mdw/catacomb/blobdiff_plain/8dd8c294e9f330eb6b975c2b96cf9bbfcd087e5e..f41f820e4b3e230d9314cc4323abf59babdd4e67:/twofish-mktab.c

diff --git a/twofish-mktab.c b/twofish-mktab.c
index 5a649f3..e30d4cc 100644
--- a/twofish-mktab.c
+++ b/twofish-mktab.c
@@ -1,6 +1,6 @@
 /* -*-c-*-
  *
- * $Id: twofish-mktab.c,v 1.1 2000/06/17 12:10:17 mdw Exp $
+ * $Id: twofish-mktab.c,v 1.3 2000/06/26 17:14:42 mdw Exp $
  *
  * Build constant tables for Twofish
  *
@@ -30,6 +30,14 @@
 /*----- Revision history --------------------------------------------------* 
  *
  * $Log: twofish-mktab.c,v $
+ * Revision 1.3  2000/06/26 17:14:42  mdw
+ * (rslog): Ensure that log(1) = 0 (not 255, as previously).  While the two
+ * are strictly equivalent, it means that the exp table is larger than it
+ * otherwise needs to be.
+ *
+ * Revision 1.2  2000/06/18 23:12:15  mdw
+ * Change typesetting of Galois Field names.
+ *
  * Revision 1.1  2000/06/17 12:10:17  mdw
  * New cipher.
  *
@@ -175,14 +183,14 @@ static void printq(const q_tab *q, const char *name)
   }
 }
 
-/*----- GF(2^8) arithmetic ------------------------------------------------*/
+/*----- %$\gf{2^8}$% arithmetic -------------------------------------------*/
 
 #define MDS_MOD 0x169
 #define RS_MOD 0x14d
 
 /* --- @mul@ --- *
  *
- * Arguments:	@unsigned x, y@ = polynomials over %$\mathrm{GF}(2^8)$%
+ * Arguments:	@unsigned x, y@ = polynomials over %$\gf{2^8}$%
  *		@unsigned m@ = modulus
  *
  * Returns:	The product of two polynomials.
@@ -219,7 +227,7 @@ static unsigned mul(unsigned x, unsigned y, unsigned m)
  * Returns:	---
  *
  * Use:		Computes an inner product of matrices over the finite field
- *		%$\mathrm{GF}(2^8)[x]/m(x)$%.  This isn't particularly rapid.
+ *		%$\gf{2^8}[x]/(m(x))$%.  This isn't particularly rapid.
  */
 
 static void mmul(octet *d, const octet *p, const octet *q,
@@ -310,7 +318,7 @@ static void rslog(void)
   unsigned i;
 
   rslog[0] = 0;
-  for (i = 0; i < 256; i++) {
+  for (i = 0; i < 255; i++) {
     rslog[x] = i;
     rsexp[i] = x;
     x <<= 1;
@@ -350,7 +358,7 @@ static void rslog(void)
   for (i = 0; i < 255 + x + 1; i++) {
     printf("0x%02x", rsexp[i % 255]);
     if (i == 255 + x)
-      puts("				\\\n}\n");
+      puts("						\\\n}\n");
     else if (i % 8 == 7)
       fputs(",			\\\n  ", stdout);
     else