X-Git-Url: https://git.distorted.org.uk/u/mdw/catacomb/blobdiff_plain/b92da8eb98f9e8ee5c86949c408c9f6e08a33c1e..2685767a6125c1620719c7de6234aedf41857b7e:/dh.h

diff --git a/dh.h b/dh.h
index 2ae710c..90fdaa3 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 1.7 2001/02/03 16:08:24 mdw Exp $
  *
  * Diffie-Hellman and related public-key systems
  *
@@ -30,6 +30,13 @@
 /*----- Revision history --------------------------------------------------* 
  *
  * $Log: dh.h,v $
+ * Revision 1.7  2001/02/03 16:08:24  mdw
+ * Add consistency checking for public keys.
+ *
+ * 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.
  *
@@ -58,6 +65,10 @@
 #  include "key.h"
 #endif
 
+#ifndef CATACOMB_KEYCHECK_H
+#  include "keycheck.h"
+#endif
+
 #ifndef CATACOMB_PGEN_H
 #  include "pgen.h"
 #endif
@@ -65,19 +76,19 @@
 /*----- Data structures ---------------------------------------------------*/
 
 typedef struct dh_param {
-  mp *p, *q;
-  mp *g;
+  mp *p, *q;				/* Prime numbers %$p$% and %$q$% */
+  mp *g;				/* Generates order-%$q$% subgroup */
 } dh_param;
 
 typedef struct dh_pub {
-  dh_param dp;
-  mp *y;
+  dh_param dp;				/* Shared parameters */		
+  mp *y;				/* Public key */
 } dh_pub;
 
 typedef struct dh_priv {
-  dh_param dp;
-  mp *x;
-  mp *y;
+  dh_param dp;				/* Shared parameters */
+  mp *x;				/* Private key */
+  mp *y;				/* %$y \equiv g^x \pmod{p}$% */
 } dh_priv;
 
 /*----- Key fetching ------------------------------------------------------*/
@@ -135,6 +146,58 @@ 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*/);
+
+/* --- @dh_checkparam@ --- *
+ *
+ * Arguments:	@keycheck *kc@ = keycheck state
+ *		@const dh_param *dp@ = pointer to the parameter set
+ *		@mp **v@ = optional vector of factors
+ *		@size_t n@ = size of vector
+ *
+ * Returns:	Zero if all OK, or return status from function.
+ *
+ * Use:		Checks a set of Diffie-Hellman parameters for consistency and
+ *		security.
+ */
+
+extern int dh_checkparam(keycheck */*kc*/, const dh_param */*dp*/,
+			 mp **/*v*/, size_t /*n*/);
+
 /*----- That's all, folks -------------------------------------------------*/
 
 #ifdef __cplusplus