General utilities cleanup. Add signature support to catcrypt. Throw in

[u/mdw/catacomb] / gf.h

diff --git a/gf.h b/gf.h
index 889cd9b..2429e95 100644 (file)
--- a/gf.h
+++ b/gf.h
@@ -1,6 +1,6 @@
 /* -*-c-*-
  *
- * $Id: gf.h,v 1.1.2.1 2004/03/21 22:39:46 mdw Exp $
+ * $Id: gf.h,v 1.4 2004/04/08 01:36:15 mdw Exp $
  *
  * Arithmetic on binary polynomials
  *
@@ -27,14 +27,6 @@
  * MA 02111-1307, USA.
  */
 
-/*----- Revision history --------------------------------------------------* 
- *
- * $Log: gf.h,v $
- * Revision 1.1.2.1  2004/03/21 22:39:46  mdw
- * Elliptic curves on binary fields work.
- *
- */
-
 #ifndef CATACOMB_GF_H
 #define CATACOMB_GF_H
 
@@ -99,6 +91,15 @@ extern mp *gf_sqr(mp */*d*/, mp */*a*/);
 
 extern void gf_div(mp **/*qq*/, mp **/*rr*/, mp */*a*/, mp */*b*/);
 
+/* --- @gf_irreduciblep@ --- *
+ *
+ * Arguments:  @mp *f@ = a polynomial
+ *
+ * Returns:    Nonzero if the polynomial is irreducible; otherwise zero.
+ */
+
+extern int gf_irreduciblep(mp */*f*/);
+
 /* --- @gf_gcd@ --- *
  *
  * Arguments:  @mp **gcd, **xx, **yy@ = where to write the results
@@ -115,6 +116,21 @@ extern void gf_div(mp **/*qq*/, mp **/*rr*/, mp */*a*/, mp */*b*/);
 extern void gf_gcd(mp **/*gcd*/, mp **/*xx*/, mp **/*yy*/,
                   mp */*a*/, mp */*b*/);
 
+/* -- @gf_modinv@ --- *
+ *
+ * Arguments:  @mp *d@ = destination
+ *             @mp *x@ = argument
+ *             @mp *p@ = modulus
+ *
+ * Returns:    The inverse %$x^{-1} \bmod p$%.
+ *
+ * Use:                Computes a modular inverse, the catch being that the
+ *             arguments and results are binary polynomials.  An assertion
+ *             fails if %$p$% has no inverse.
+ */
+
+extern mp *gf_modinv(mp */*d*/, mp */*x*/, mp */*p*/);
+
 /*----- That's all, folks -------------------------------------------------*/
 
 #ifdef __cplusplus