/* -*-c-*-
*
- * $Id: bbs.h,v 1.3 2000/02/12 18:21:02 mdw Exp $
+ * $Id$
*
* The Blum-Blum-Shub random bit generator
*
* (c) 1999 Straylight/Edgeware
*/
-/*----- Licensing notice --------------------------------------------------*
+/*----- Licensing notice --------------------------------------------------*
*
* This file is part of Catacomb.
*
* 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 1.3 2000/02/12 18:21:02 mdw
- * Overhaul of key management (again).
- *
- * 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
# include "grand.h"
#endif
+#ifndef CATACOMB_KEY_H
+# include "key.h"
+#endif
+
#ifndef CATACOMB_MP_H
# include "mp.h"
#endif
/* --- 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 -----------------------------------------------*/
*
* 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
+ * 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
* 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*/, unsigned /*nbits*/, grand */*r*/,
+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.
*/
/* --- 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 -------------------------------------------------*/
projects / u / mdw / catacomb / blobdiff