3 * $Id: pgen.h,v 1.2 1999/11/20 22:23:05 mdw Exp $
5 * Finding and testing prime numbers
7 * (c) 1999 Straylight/Edgeware
10 /*----- Licensing notice --------------------------------------------------*
12 * This file is part of Catacomb.
14 * Catacomb is free software; you can redistribute it and/or modify
15 * it under the terms of the GNU Library General Public License as
16 * published by the Free Software Foundation; either version 2 of the
17 * License, or (at your option) any later version.
19 * Catacomb is distributed in the hope that it will be useful,
20 * but WITHOUT ANY WARRANTY; without even the implied warranty of
21 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
22 * GNU Library General Public License for more details.
24 * You should have received a copy of the GNU Library General Public
25 * License along with Catacomb; if not, write to the Free
26 * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
30 /*----- Revision history --------------------------------------------------*
33 * Revision 1.2 1999/11/20 22:23:05 mdw
34 * Add multiply-and-add function for Diffie-Hellman safe prime generation.
36 * Revision 1.1 1999/11/19 13:17:57 mdw
37 * Prime number generator and tester.
48 /*----- Header files ------------------------------------------------------*/
58 /*----- Constants ---------------------------------------------------------*/
60 #define PGEN_COMPOSITE (-1) /* Number is definitely composite */
61 #define PGEN_MAYBE (0) /* Number may be prime */
62 #define PGEN_PRIME (1) /* Number is definitely prime */
64 /*----- Data structures ---------------------------------------------------*/
68 unsigned char r
[NPRIME
];
71 /*----- Functions provided ------------------------------------------------*/
73 /* --- @pgen_create@ --- *
75 * Arguments: @pgen *p@ = pointer to prime generation context
76 * @mp *m@ = pointer to initial number to test
78 * Returns: One of the @PGEN@ constants above.
80 * Use: Tests an initial number for primality by computing its
81 * residue modulo various small prime numbers. This is fairly
82 * quick, but not particularly certain. If a @PGEN_MAYBE@
83 * result is returned, perform Rabin-Miller tests to confirm.
86 extern int pgen_create(pgen */
*p*/
, mp */
*m*/
);
88 /* --- @pgen_destroy@ --- *
90 * Arguments: @pgen *p@ = pointer to prime generation context
94 * Use: Discards a context and all the resources it holds.
97 extern void pgen_destroy(pgen */
*p*/
);
99 /* --- @pgen_step@ --- *
101 * Arguments: @pgen *p@ = pointer to prime generation context
102 * @mpw step@ = how much to step the number
104 * Returns: One of the @PGEN@ constants above.
106 * Use: Steps a number by a small amount. Stepping is much faster
107 * than initializing with a new number. The test performed is
108 * the same simple one used by @ptab_create@, so @PGEN_MAYBE@
109 * results should be followed up by a Rabin-Miller test.
112 extern int pgen_step(pgen */
*p*/
, mpw
/*step*/);
114 /* --- @pgen_muladd@ --- *
116 * Arguments: @pgen *p@ = destination prime generation context
117 * @const pgen *q@ = source prime generation context
118 * @mpw m@ = number to multiply by
119 * @mpw a@ = number to add
121 * Returns: One of the @PGEN@ constants above.
123 * Use: Multiplies the number in a prime generation context by a
124 * small value and then adds a small value. The destination
125 * should either be uninitialized or the same as the source.
127 * Common things to do include multiplying by 2 and adding 0 to
128 * turn a prime into a jump for finding other primes with @q@ as
129 * a factor of @p - 1@, or multiplying by 2 and adding 1.
132 extern int pgen_muladd(pgen */
*p*/
, const pgen */
*q*/
, mpw
/*m*/, mpw
/*a*/);
134 /* --- @pgen_jump@ --- *
136 * Arguments: @pgen *p@ = pointer to prime generation context
137 * @pgen *j@ = pointer to another generation context
139 * Returns: One of the @PGEN@ constants above.
141 * Use: Steps a number by a large amount. Even so, jumping is much
142 * faster than initializing a new number. The test peformed is
143 * the same simple one used by @ptab_create@, so @PGEN_MAYBE@
144 * results should be followed up by a Rabin-Miller test.
146 * Note that the number stored in the @j@ context is probably
147 * better off being even than prime. The important thing is
148 * that all of the residues for the number have already been
152 extern int pgen_jump(pgen */
*p*/
, pgen */
*j*/
);
154 /*----- That's all, folks -------------------------------------------------*/