X-Git-Url: https://git.distorted.org.uk/u/mdw/catacomb/blobdiff_plain/4f743df55ac05e51bc69aaabd188132f2f94543b..6a7dce9165a4a707382e49877334353618fcad9a:/bbs.h

diff --git a/bbs.h b/bbs.h
index 485fb76..30fb474 100644
--- a/bbs.h
+++ b/bbs.h
@@ -1,13 +1,13 @@
 /* -*-c-*-
  *
- * $Id: bbs.h,v 1.2 1999/12/22 15:52:08 mdw Exp $
+ * $Id$
  *
  * The Blum-Blum-Shub random bit generator
  *
  * (c) 1999 Straylight/Edgeware
  */
 
-/*----- Licensing notice --------------------------------------------------* 
+/*----- Licensing notice --------------------------------------------------*
  *
  * This file is part of Catacomb.
  *
@@ -15,43 +15,32 @@
  * it under the terms of the GNU Library General Public License as
  * published by the Free Software Foundation; either version 2 of the
  * License, or (at your option) any later version.
- * 
+ *
  * Catacomb is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  * GNU Library General Public License for more details.
- * 
+ *
  * You should have received a copy of the GNU Library General Public
  * License along with Catacomb; if not, write to the Free
  * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
  * MA 02111-1307, USA.
  */
 
-/*----- Revision history --------------------------------------------------* 
- *
- * $Log: bbs.h,v $
- * Revision 1.2  1999/12/22 15:52:08  mdw
- * Rename `bbs_params' to `bbs_param' for consistency.
- *
- * Revision 1.1  1999/12/10 23:14:59  mdw
- * Blum-Blum-Shub generator, and Blum-Goldwasser encryption.
- *
- */
-
 /*----- Notes on the BBS generator ----------------------------------------*
  *
  * The Blum-Blum-Shub generator takes the least significant bits from the
  * sequence %$x_i = x_{i - 1}^2 \bmod n$%, where %$n = pq$% is the product of
  * two primes %$p$% and %$q$%, each of which are congruent to %$3 \bmod 4$%.
  * For maximum period of the generator, %$(p - 1)/2$% and %$(q - 1)/1$%
- * should be coprime.  It is safe to use the least significant %$\log \log
- * n$% bits of each step in the sequence -- an adversary must factor the
- * modulus before being able to work forwards or backwards.  The output of
- * the generator cannot be distinguished from a (uniform, independent) random
- * sequence of bits using any polynomial-time test.  This is by far the
- * strongest pseudorandom number generator provided in Catacomb, and by far
- * the slowest too.  For normal use, the standard Catacomb @rand@ generator
- * should be more than adequate.
+ * should be coprime.  It is safe to use the least significant
+ * %$\log \log n$% bits of each step in the sequence -- an adversary must
+ * factor the modulus before being able to work forwards or backwards.  The
+ * output of the generator cannot be distinguished from a (uniform,
+ * independent) random sequence of bits using any polynomial-time test.  This
+ * is by far the strongest pseudorandom number generator provided in
+ * Catacomb, and by far the slowest too.  For normal use, the standard
+ * Catacomb @rand@ generator should be more than adequate.
  */
 
 #ifndef CATACOMB_BBS_H
@@ -69,6 +58,10 @@
 #  include "grand.h"
 #endif
 
+#ifndef CATACOMB_KEY_H
+#  include "key.h"
+#endif
+
 #ifndef CATACOMB_MP_H
 #  include "mp.h"
 #endif
@@ -95,10 +88,34 @@ typedef struct bbs {
 
 /* --- Parameters --- */
 
-typedef struct bbs_param {
+typedef struct bbs_pub {
+  mp *n;
+} bbs_pub;
+
+typedef struct bbs_priv {
   mp *p, *q;				/* Prime factors (3 mod 4) */
   mp *n;				/* Product @pq@ -- a Blum integer */
-} bbs_param;
+} bbs_priv;
+
+/*----- Key fetching ------------------------------------------------------*/
+
+extern const key_fetchdef bbs_pubfetch[];
+#define BBS_PUBFETCHSZ 3
+
+extern const key_fetchdef bbs_privfetch[];
+#define BBS_PRIVFETCHSZ 7
+
+/* --- @bbs_pubfree@, @bbs_privfree@ --- *
+ *
+ * Arguments:	@bbs_pub *bp@, @bbs_priv *bp@ = pointer to key block
+ *
+ * Returns:	---
+ *
+ * Use:		Frees a BBS key block.
+ */
+
+extern void bbs_pubfree(bbs_pub */*bp*/);
+extern void bbs_privfree(bbs_priv */*bp*/);
 
 /*----- The basic generator -----------------------------------------------*/
 
@@ -189,75 +206,66 @@ extern uint32 bbs_bits(bbs */*b*/, unsigned /*bits*/);
  *
  *		If a generator is seeded, %$b$% bits are extracted, and then
  *		@bbs_wrap@ is called, the generator will have been stepped
- *		%$\lceil b/k \rceil% times.
+ *		%$\lceil b/k \rceil$% times.
  */
 
 extern void bbs_wrap(bbs */*b*/);
 
 /*----- Large forwards and backwards jumps --------------------------------*/
 
-/* --- @bbs_ff@ --- *
- *
- * Arguments:	@bbs *b@ = pointer to a BBS generator state
- *		@bbs_param *bp@ = pointer to BBS modulus factors
- *		@unsigned long n@ = number of steps to make
- *
- * Returns:	---
- *
- * Use:		`Fast-forwards' a Blum-Blum-Shub generator by @n@ steps.
- *		Requires the factorization of the Blum modulus to do this
- *		efficiently.
- */
-
-extern void bbs_ff(bbs */*b*/, bbs_param */*bp*/, unsigned long /*n*/);
-
-/* --- @bbs_rew@ --- *
+/* --- @bbs_{ff,rew}{,n}@ --- *
  *
  * Arguments:	@bbs *b@ = pointer to a BBS generator state
- *		@bbs_param *bp@ = pointer to BBS modulus factors
- *		@unsigned long n@ = number of steps to make
+ *		@const bbs_priv *bp@ = pointer to BBS modulus factors
+ *		@mp *n@, @unsigned long n@ = number of steps to make
  *
  * Returns:	---
  *
- * Use:		`Rewinds' a Blum-Blum-Shub generator by @n@ steps.
- *		Requires the factorization of the Blum modulus to do this
- *		at all.
+ * Use:		`Fast-forwards' or rewinds a Blum-Blum-Shub generator by @n@
+ *		steps.  The @...n@ versions take an @unsigned long@ argument;
+ *		the non-@...n@ versions a multiprecision integer.  If @n@ is
+ *		negative then the generator is stepped in the reverse
+ *		direction.
  */
 
-extern void bbs_rew(bbs */*b*/, bbs_param */*bp*/, unsigned long /*n*/);
+extern void bbs_ff(bbs */*b*/, const bbs_priv */*bp*/, mp */*n*/);
+extern void bbs_ffn(bbs */*b*/, const bbs_priv */*bp*/, unsigned long /*n*/);
+extern void bbs_rew(bbs */*b*/, const bbs_priv */*bp*/, mp */*n*/);
+extern void bbs_rewn(bbs */*b*/, const bbs_priv */*bp*/, unsigned long /*n*/);
 
 /*----- Parameter generation ----------------------------------------------*/
 
 /* --- @bbs_gen@ --- *
  *
- * Arguments:	@bbs_param *bp@ = pointer to parameter block
- *		@mp *p, *q@ = initial numbers to search from
- *		@size_t n@ = number of attempts to make
+ * Arguments:	@bbs_priv *bp@ = pointer to parameter block
+ *		@unsigned nbits@ = number of bits in the modulus
+ *		@grand *r@ = pointer to random number source
+ *		@unsigned n@ = number of attempts to make
  *		@pgen_proc *event@ = event handler function
  *		@void *ectx@ = argument for event handler
  *
  * Returns:	If it worked OK, @PGEN_DONE@, otherwise @PGEN_ABORT@.
  *
  * Use:		Finds two prime numbers %$p'$% and %$q'$% such that both are
- *		congruent to %$3 \bmod 4$%, and  $(p - 1)/2$% and
+ *		congruent to %$3 \bmod 4$%, and	 $(p - 1)/2$% and
  *		%$(q - 1)/2$% have no common factors.  The product %$n = pq$%
  *		is eminently suitable for use as a modulus in a Blum-Blum-
  *		Shub pseudorandom bit generator.
  */
 
-extern int bbs_gen(bbs_param */*bp*/, mp */*p*/, mp */*q*/, size_t /*n*/,
-		   pgen_proc */*event*/, void */*ectx*/);
+extern int bbs_gen(bbs_priv */*bp*/, unsigned /*nbits*/, grand */*r*/,
+		   unsigned /*n*/, pgen_proc */*event*/, void */*ectx*/);
 
 /*----- Generic random number generator interface -------------------------*/
 
 /* --- @bbs_rand@ --- *
  *
- * Arguments:   @mp *m@ = modulus
+ * Arguments:	@mp *m@ = modulus
  *		@mp *x@ = initial seed
  *
- * Returns:     Pointer to a generic generator.
+ * Returns:	Pointer to a generic generator.
  *
- * Use:         Constructs a generic generator interface over a
+ * Use:		Constructs a generic generator interface over a
  *		Blum-Blum-Shub generator.
  */
 
@@ -266,7 +274,17 @@ extern grand *bbs_rand(mp */*m*/, mp */*x*/);
 /* --- Blum-Blum-Shub-specific misc op codes --- */
 
 enum {
-  BBS_SET = GRAND_SPECIFIC		/* @mp *x@ */
+  BBS_SET = GRAND_SPECIFIC('B'),	/* @mp *x@ */
+  BBS_STEP,				/* @void@ */
+  BBS_STEPSZ,				/* @void@ */
+  BBS_BITS,				/* @unsigned bits, uint32 *w@ */
+  BBS_WRAP,				/* @void@ */
+  BBS_FF,				/* @bbs_priv *p, mp *n@ */
+  BBS_FFN,				/* @bbs_priv *p, unsigned long n@ */
+  BBS_REW,				/* @bbs_priv *p, mp *n@ */
+  BBS_REWN,				/* @bbs_priv *p, unsigned long n@ */
+  BBS_MOD,				/* @mp **n@ */
+  BBS_STATE				/* @mp **x@ */
 };
 
 /*----- That's all, folks -------------------------------------------------*/