3 * $Id: group.h,v 1.4 2004/04/08 01:36:15 mdw Exp $
5 * General cyclic group abstraction
7 * (c) 2004 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 #ifndef CATACOMB_GROUP_H
31 #define CATACOMB_GROUP_H
37 /*----- Header files ------------------------------------------------------*/
39 #include <mLib/dstr.h>
41 #ifndef CATACOMB_BUF_H
49 #ifndef CATACOMB_GRAND_H
57 #ifndef CATACOMB_QDPARSE_H
61 /*----- Data structures ---------------------------------------------------*/
64 typedef struct ge ge
; /* Group element (abstract type) */
67 typedef struct group_
{
68 const struct group_ops
*ops
; /* Operations table */
69 size_t nbits
; /* Size of an element in bits */
70 size_t noctets
; /* Size of raw element in octets */
71 ge
*i
; /* Identity element */
72 ge
*g
; /* Generator element */
73 mp
*r
; /* Order of the generator */
77 typedef struct group_expfactor
{
78 ge
*base
; /* The base */
79 mp
*exp
; /* The exponent */
82 typedef struct group_ops
{
83 unsigned ty
; /* Type of this group */
85 /* --- Memory management --- */
87 void (*destroygroup
)(group */
*g*/
);
88 ge
*(*create
)(group */
*g*/
);
89 void (*copy
)(group */
*g*/
, ge */
*d*/
, ge */
*x*/
);
90 void (*burn
)(group */
*g*/
, ge */
*x*/
);
91 void (*destroy
)(group */
*g*/
, ge */
*e*/
);
93 /* --- Comparisons --- */
95 int (*samep
)(group */
*g*/
, group */
*h*/
);
96 int (*eq
)(group */
*g*/
, ge */
*x*/
, ge */
*y*/
);
97 int (*identp
)(group */
*g*/
, ge */
*x*/
);
99 /* --- Other stuff --- */
101 const char *(*check
)(group */
*g*/
, grand */
*gr*/
);
103 /* --- Arithmetic --- */
105 void (*mul
)(group */
*g*/
, ge */
*d*/
, ge */
*x*/
, ge */
*y*/
);
106 void (*sqr
)(group */
*g*/
, ge */
*d*/
, ge */
*x*/
);
107 void (*inv
)(group */
*g*/
, ge */
*d*/
, ge */
*x*/
);
108 void (*div
)(group */
*g*/
, ge */
*d*/
, ge */
*x*/
, ge */
*y*/
);
109 void (*exp
)(group */
*g*/
, ge */
*d*/
, ge */
*x*/
, mp */
*n*/
);
110 void (*mexp
)(group */
*g*/
, ge */
*d*/
,
111 const group_expfactor */
*f*/
, size_t /*n*/);
113 /* --- Debugging --- */
115 int (*read
)(group */
*g*/
, ge */
*d*/
,
116 const mptext_ops */
*ops*/
, void */
*p*/
);
117 int (*write
)(group */
*g*/
, ge */
*x*/
,
118 const mptext_ops */
*ops*/
, void */
*p*/
);
120 /* --- Conversions --- */
122 mp
*(*toint
)(group */
*g*/
, mp */
*d*/
, ge */
*x*/
);
123 int (*fromint
)(group */
*g*/
, ge */
*d*/
, mp */
*x*/
);
124 int (*toec
)(group */
*g*/
, ec */
*d*/
, ge */
*x*/
);
125 int (*fromec
)(group */
*g*/
, ge */
*d*/
, ec */
*p*/
);
126 int (*tobuf
)(group */
*h*/
, buf */
*b*/
, ge */
*x*/
);
127 int (*frombuf
)(group */
*h*/
, buf */
*b*/
, ge */
*d*/
);
128 int (*toraw
)(group */
*h*/
, buf */
*b*/
, ge */
*x*/
);
129 int (*fromraw
)(group */
*h*/
, buf */
*b*/
, ge */
*d*/
);
134 GTY_PRIME
, /* Prime field subgroup */
135 GTY_BINARY
, /* Binary feld subgroup */
136 GTY_EC
/* Elliptic curve group */
139 #define G_DESTROYGROUP(g) (g)->ops->destroygroup((g))
140 #define G_CREATE(g) (g)->ops->create((g))
141 #define G_COPY(g, d, x) (g)->ops->copy((g), (d), (x))
142 #define G_BURN(g, x) (g)->ops->burn((g), (x))
143 #define G_DESTROY(g, x) (g)->ops->destroy((g), (x))
145 #define G_SAMEP(g, h) (g)->ops->samep((g), (h))
146 #define G_EQ(g, x, y) (g)->ops->eq((g), (x), (y))
147 #define G_IDENTP(g, x) (g)->ops->identp((g), (x))
149 #define G_CHECK(g, gr) (g)->ops->check((g), (gr))
151 #define G_MUL(g, d, x, y) (g)->ops->mul((g), (d), (x), (y))
152 #define G_SQR(g, d, x) (g)->ops->sqr((g), (d), (x))
153 #define G_INV(g, d, x) (g)->ops->inv((g), (d), (x))
154 #define G_DIV(g, d, x, y) (g)->ops->div((g), (d), (x), (y))
155 #define G_EXP(g, d, x, n) (g)->ops->exp((g), (d), (x), (n))
156 #define G_MEXP(g, d, f, n) (g)->ops->mexp((g), (d), (f), (n))
158 #define G_READ(g, d, o, p) (g)->ops->read((g), (d), (o), (p))
159 #define G_WRITE(g, x, o, p) (g)->ops->write((g), (x), (o), (p))
161 #define G_TOINT(g, d, x) (g)->ops->toint((g), (d), (x))
162 #define G_FROMINT(g, d, x) (g)->ops->fromint((g), (d), (x))
163 #define G_TOEC(g, d, x) (g)->ops->toec((g), (d), (x))
164 #define G_FROMEC(g, d, p) (g)->ops->fromec((g), (d), (p))
165 #define G_TOBUF(g, b, x) (g)->ops->tobuf((g), (b), (x))
166 #define G_FROMBUF(g, b, d) (g)->ops->frombuf((g), (b), (d))
167 #define G_TORAW(g, b, x) (g)->ops->toraw((g), (b), (x))
168 #define G_FROMRAW(g, b, d) (g)->ops->fromraw((g), (b), (d))
170 /*----- Handy functions ---------------------------------------------------*/
172 /* --- @group_check@ --- *
174 * Arguments: @group *g@ = an abstract group
175 * @ge *x@ = a group element
177 * Returns: Zero on success, nonzero for failure.
179 * Use: Checks that @x@ is a valid group element. This may take a
180 * while, since it checks that %$x^h \ne 1$%.
183 extern int group_check(group */
*g*/
, ge */
*x*/
);
185 /* --- @group_samep@ --- *
187 * Arguments: @group *g, *h@ = two abstract groups
189 * Returns: Nonzero if the groups are in fact identical (not just
192 * Use: Checks to see whether two groups are actually the same. This
193 * function does the full check: the group operatrion @samep@
194 * just does the group-specific details.
197 extern int group_samep(group */
*g*/
, group */
*h*/
);
199 /*----- Textual I/O on group elements -------------------------------------*/
201 extern int group_readstring(group */
*g*/
, ge */
*d*/
,
202 const char */
*p*/
, char **/
*end*/
);
203 extern int group_writestring(group */
*g*/
, ge */
*d*/
,
204 char */
*p*/
, size_t /*sz*/);
206 extern int group_readfile(group */
*g*/
, ge */
*d*/
, FILE */
*fp*/
);
207 extern int group_writefile(group */
*g*/
, ge */
*x*/
, FILE */
*fp*/
);
209 extern int group_readdstr(group */
*g*/
, ge */
*d*/
,
210 dstr */
*dd*/
, size_t */
*off*/
);
211 extern int group_writedstr(group */
*g*/
, ge */
*x*/
, dstr */
*d*/
);
213 /*----- Standard implementations ------------------------------------------*/
215 /* --- @group_stdidentp@ --- *
217 * Arguments: @group *g@ = abstract group
218 * @ge *x@ = group element
220 * Returns: Nonzero if %$x$% is the group identity.
223 extern int group_stdidentp(group */
*g*/
, ge */
*x*/
);
225 /* --- @group_stdcheck@ --- *
227 * Arguments: @group *g@ = abstract group
228 * @grand *gr@ = random number source.
230 * Returns: Null on success, or a pointer to an error message.
233 extern const char *group_stdcheck(group */
*g*/
, grand */
*gr*/
);
235 /* --- @group_stdsqr@ --- *
237 * Arguments: @group *g@ = abstract group
238 * @ge *d@ = destination pointer
239 * @ge *x@ = group element
243 * Use: Computes %$d = x^2$% as %$d = x x$%.
246 extern void group_stdsqr(group */
*g*/
, ge */
*d*/
, ge */
*x*/
);
248 /* --- @group_stddiv@ --- *
250 * Arguments: @group *g@ = abstract group
251 * @ge *d@ = destination pointer
257 * Use: Computes %$d = x/y$% as %$d = x y^{-1}$%.
260 extern void group_stddiv(group */
*g*/
, ge */
*d*/
, ge */
*x*/
, ge */
*y*/
);
262 /* --- @group_stdexp@ --- *
264 * Arguments: @group *g@ = abstract group
265 * @ge *d@ = destination pointer
266 * @ge *x@ = base element
271 * Use: Computes %$d = x^n$% efficiently.
274 extern void group_stdexp(group */
*g*/
, ge */
*d*/
, ge */
*x*/
, mp */
*n*/
);
276 /* --- @group_stdmexp@ --- *
278 * Arguments: @group *g@ = abstract group
279 * @ge *d@ = destination pointer
280 * @const group_expfactor *f@ = vector of factors
281 * @size_t n@ = number of factors
285 * Use: Computes %$d = g_0^{x_0} g_1^{x_1} \ldots$% efficiently.
288 extern void group_stdmexp(group */
*g*/
, ge */
*d*/
,
289 const group_expfactor */
*f*/
, size_t /*n*/);
291 /* --- @group_stdtoec@ --- *
293 * Arguments: @group *g@ = abstract group
294 * @ec *d@ = destination point
295 * @ge *x@ = group element
297 * Returns: @-1@, indicating failure.
299 * Use: Fails to convert a group element to an elliptic curve point.
302 extern int group_stdtoec(group */
*g*/
, ec */
*d*/
, ge */
*x*/
);
304 /* --- @group_stdfromec@ --- *
306 * Arguments: @group *g@ = abstract group
307 * @ge *d@ = destination pointer
308 * @ec *p@ = elliptic curve point
310 * Returns: Zero for success, @-1@ on failure.
312 * Use: Converts %$p$% to a group element by converting its %$x$%-
316 extern int group_stdfromec(group */
*g*/
, ge */
*d*/
, ec */
*p*/
);
318 /*----- Prime field subgroups ---------------------------------------------*/
320 typedef struct gprime_param
{
321 mp
*p
, *q
; /* Prime numbers %$p$% and %$q$% */
322 mp
*g
; /* Generates order-%$q$% subgroup */
325 /* --- @group_prime@ --- *
327 * Arguments: @const gprime_param *gp@ = group parameters
329 * Returns: A pointer to the group, or null.
331 * Use: Constructs an abstract group interface for a subgroup of a
332 * prime field. Group elements are @mp *@ pointers.
335 group
*group_prime(const gprime_param */
*gp*/
);
337 /*----- Elliptic curve groups ---------------------------------------------*/
339 /* --- @group_ec@ --- *
341 * Arguments: @const ec_info *ei@ = elliptic curve parameters
343 * Returns: A pointer to the group, or null.
345 * Use: Constructs an abstract group interface for an elliptic curve
346 * group. Group elements are @ec@ structures. The contents of
347 * the @ec_info@ structure becomes the property of the @group@
348 * object; you can (and should) free the structure itself, but
349 * calling @ec_freeinfo@ on it is not allowed.
352 group
*group_ec(const ec_info */
*ei*/
);
354 /*----- General group initialization --------------------------------------*/
356 /* --- @group_parse@ --- *
358 * Arguments: @qd_parse *qd@ = quick-and-dirty parser
360 * Returns: Group pointer, or null for failure.
362 * Use: Parses a group description and returns the group. This has
363 * the form `TYPE { SPEC }' where TYPE is `prime' or `ec', and
364 * SPEC is the appropriate kind of group specification of the
368 extern group
*group_parse(qd_parse */
*qd*/
);
370 /* --- @group_fromstring@ --- *
372 * Arguments: @const char *p@ = pointer to string to read
373 * @group **gg@ = where to put the group pointer
375 * Returns: Null if OK, or an error string.
377 * Use: Parses a group spec from a string, and returns the group.
380 extern const char *group_fromstring(const char */
*p*/
, group
**/
*gg*/
);
382 /*----- That's all, folks -------------------------------------------------*/