From 1269467c574b73b63e596de3e5be561014215c99 Mon Sep 17 00:00:00 2001
From: mdw <mdw>
Date: Sat, 29 Jul 2000 10:01:16 +0000
Subject: [PATCH] Supply commentry for the Diffie-Hellman parameters.  Add
 Lim-Lee parameter generation.

---
 dh.h | 56 ++++++++++++++++++++++++++++++++++++++++++++++++--------
 1 file changed, 48 insertions(+), 8 deletions(-)

diff --git a/dh.h b/dh.h
index 2ae710c..c2f2311 100644
--- a/dh.h
+++ b/dh.h
@@ -1,6 +1,6 @@
 /* -*-c-*-
  *
- * $Id: dh.h,v 1.5 2000/07/01 11:20:51 mdw Exp $
+ * $Id: dh.h,v 1.6 2000/07/29 10:01:16 mdw Exp $
  *
  * Diffie-Hellman and related public-key systems
  *
@@ -30,6 +30,10 @@
 /*----- Revision history --------------------------------------------------* 
  *
  * $Log: dh.h,v $
+ * Revision 1.6  2000/07/29 10:01:16  mdw
+ * Supply commentry for the Diffie-Hellman parameters.  Add Lim-Lee
+ * parameter generation.
+ *
  * Revision 1.5  2000/07/01 11:20:51  mdw
  * New functions for freeing public and private keys.
  *
@@ -64,19 +68,19 @@
 
 /*----- Data structures ---------------------------------------------------*/
 
-typedef struct dh_param {
-  mp *p, *q;
+typedef struct dh_param {		/* Prime numbers %$p$% and %$q$% */
+  mp *p, *q;				/* Generates order-%$q$% subgroup */
   mp *g;
 } dh_param;
 
-typedef struct dh_pub {
-  dh_param dp;
+typedef struct dh_pub {			/* Shared parameters */
+  dh_param dp;				/* Public key */
   mp *y;
 } dh_pub;
 
-typedef struct dh_priv {
-  dh_param dp;
-  mp *x;
+typedef struct dh_priv {		/* Shared parameters */
+  dh_param dp;				/* Private key */
+  mp *x;				/* %$y \equiv g^x \pmod{p}$% */
   mp *y;
 } dh_priv;
 
@@ -135,6 +139,42 @@ extern int dh_gen(dh_param */*dp*/, unsigned /*ql*/, unsigned /*pl*/,
 		  unsigned /*steps*/, grand */*r*/, pgen_proc */*event*/,
 		  void */*ectx*/);
 
+/* --- @dh_limlee@ --- *
+ *
+ * Arguments:	@dh_param *dp@ = pointer to output parameter block
+ *		@unsigned ql@ = length of smallest factor of %$(p - 1)/2$%
+ *		@unsigned pl@ = length of %$p$% in bits
+ *		@unsigned flags@ = other generation flags
+ *		@unsigned steps@ = number of steps to go
+ *		@grand *r@ = random number source
+ *              @pgen_proc *oev@ = outer event handler function
+ *              @void *oec@ = argument for the outer event handler
+ *              @pgen_proc *iev@ = inner event handler function
+ *              @void *iec@ = argument for the inner event handler
+ *              @size_t *nf@, @mp ***f@ = output array for factors
+ *
+ * Returns:	@PGEN_DONE@ if it worked, @PGEN_ABORT@ if it didn't.
+ *
+ * Use:		Generates Diffie-Hellman parameters based on a Lim-Lee prime.
+ *
+ *		The modulus is a large prime %$p = 2 \prod q_i + 1$%, @pl@
+ *		bits long, where the %$q_i$% are smaller primes each at least
+ *		@ql@ bits long.  It is safe to set @nf@ and @f@ to zero if
+ *		you're not interested in the factor values.
+ *
+ *		The returned %$g$% generates a subgroup of order %$q_0$% (the
+ *		first factor, returned as @f[0]@), if the flag @DH_SUBGROUP@
+ *		is set on entry; otherwise %$g$% will have order
+ *		%$(p - 1)/2$%.
+ */
+
+#define DH_SUBGROUP 1u
+
+extern int dh_limlee(dh_param */*dp*/, unsigned /*ql*/, unsigned /*pl*/,
+		     unsigned /*flags*/, unsigned /*steps*/, grand */*r*/,
+		     pgen_proc */*oev*/, void */*oec*/, pgen_proc */*iev*/,
+		     void */*iec*/, size_t */*nf*/, mp ***/*f*/);
+
 /*----- That's all, folks -------------------------------------------------*/
 
 #ifdef __cplusplus
-- 
2.11.0