/* -*-c-*-
*
- * $Id: ec-info.c,v 1.1 2004/03/27 17:54:11 mdw Exp $
+ * $Id: ec-info.c,v 1.2 2004/04/01 12:50:09 mdw Exp $
*
* Elliptic curve information management
*
/*----- Revision history --------------------------------------------------*
*
* $Log: ec-info.c,v $
+ * Revision 1.2 2004/04/01 12:50:09 mdw
+ * Add cyclic group abstraction, with test code. Separate off exponentation
+ * functions for better static linking. Fix a buttload of bugs on the way.
+ * Generally ensure that negative exponents do inversion correctly. Add
+ * table of standard prime-field subgroups. (Binary field subgroups are
+ * currently unimplemented but easy to add if anyone ever finds a good one.)
+ *
* Revision 1.1 2004/03/27 17:54:11 mdw
* Standard curves and curve checking.
*
return (0);
}
+/* --- @getinfo@ --- *
+ *
+ * Arguments: @ec_info *ei@ = where to write the information
+ * @ecdata *ed@ = raw data
+ *
+ * Returns: ---
+ *
+ * Use: Loads elliptic curve information about one of the standard
+ * curves.
+ */
+
+static void getinfo(ec_info *ei, ecdata *ed)
+{
+ field *f;
+
+ switch (ed->ftag) {
+ case FTAG_PRIME:
+ f = field_prime(&ed->p);
+ ei->c = ec_primeproj(f, &ed->a, &ed->b);
+ break;
+ case FTAG_NICEPRIME:
+ f = field_niceprime(&ed->p);
+ ei->c = ec_primeproj(f, &ed->a, &ed->b);
+ break;
+ case FTAG_BINPOLY:
+ f = field_binpoly(&ed->p);
+ ei->c = ec_binproj(f, &ed->a, &ed->b);
+ break;
+ default:
+ abort();
+ }
+
+ EC_CREATE(&ei->g); ei->g.x = &ed->gx; ei->g.y = &ed->gy; ei->g.z = 0;
+ ei->r = &ed->r; ei->h = &ed->h;
+}
+
/* --- @ec_infoparse@ --- *
*
* Arguments: @qd_parse *qd@ = parser context
* Returns: Zero on success, nonzero on failure.
*
* Use: Parses an elliptic curve information string, and stores the
- * information in @ei@. This has the form
+ * information in @ei@. This is either the name of a standard
+ * curve, or it has the form
*
* * elliptic curve description
* * optional `/'
ec_curve *c = 0;
field *f;
ec g = EC_INIT;
+ const ecentry *ee;
mp *r = MP_NEW, *h = MP_NEW;
+ for (ee = ectab; ee->name; ee++) {
+ if (qd_enum(qd, ee->name) >= 0) {
+ getinfo(ei, ee->data);
+ goto found;
+ }
+ }
if ((c = ec_curveparse(qd)) == 0) goto fail;
qd_delim(qd, '/'); if (!ec_ptparse(qd, &g)) goto fail;
qd_delim(qd, ':'); if ((r = qd_getmp(qd)) == 0) goto fail;
qd_delim(qd, '*'); if ((h = qd_getmp(qd)) == 0) goto fail;
-
ei->c = c; ei->g = g; ei->r = r; ei->h = h;
+
+found:
return (0);
fail:
return (-1);
}
-/* --- @getinfo@ --- *
- *
- * Arguments: @ec_info *ei@ = where to write the information
- * @const ecdata *ed@ = raw data
- *
- * Returns: ---
- *
- * Use: Loads elliptic curve information about one of the standard
- * curves.
- */
-
-static mp *getmp(const mpw *v, size_t n)
-{
- mp *x = mp_new(n, 0);
- memcpy(x->v, v, MPWS(n));
- return (x);
-}
-
-static void getinfo(ec_info *ei, const ecdata *ed)
-{
- field *f;
- mp *p = 0, *a = 0, *b = 0;
-
- switch (ed->ftag) {
- case FTAG_PRIME:
- p = getmp(ed->p, ed->psz);
- f = field_prime(p);
- a = getmp(ed->a, ed->asz); b = getmp(ed->b, ed->bsz);
- ei->c = ec_primeproj(f, a, b);
- break;
- case FTAG_NICEPRIME:
- p = getmp(ed->p, ed->psz);
- f = field_niceprime(p);
- a = getmp(ed->a, ed->asz); b = getmp(ed->b, ed->bsz);
- ei->c = ec_primeproj(f, a, b);
- break;
- case FTAG_BINPOLY:
- p = getmp(ed->p, ed->psz);
- f = field_binpoly(p);
- a = getmp(ed->a, ed->asz); b = getmp(ed->b, ed->bsz);
- ei->c = ec_binproj(f, a, b);
- break;
- default:
- abort();
- }
-
- EC_CREATE(&ei->g);
- ei->g.x = getmp(ed->gx, ed->gxsz);
- ei->g.y = getmp(ed->gy, ed->gysz);
- ei->g.z = 0;
- ei->r = getmp(ed->r, ed->rsz);
- ei->h = getmp(ed->h, ed->hsz);
-
- MP_DROP(p);
- MP_DROP(a);
- MP_DROP(b);
-}
-
/* --- @ec_getinfo@ --- *
*
* Arguments: @ec_info *ei@ = where to write the information
const char *ec_getinfo(ec_info *ei, const char *p)
{
qd_parse qd;
- const ecentry *ee;
qd.p = p;
qd.e = 0;
- for (ee = ectab; ee->name; ee++) {
- if (qd_enum(&qd, ee->name) >= 0) {
- getinfo(ei, ee->data);
- goto found;
- }
- }
if (ec_infoparse(&qd, ei))
return (qd.e);
-found:
if (!qd_eofp(&qd)) {
ec_freeinfo(ei);
return ("junk found at end of string");
return (0);
}
+/* --- @ec_sameinfop@ --- *
+ *
+ * Arguments: @ec_info *ei, *ej@ = two elliptic curve parameter sets
+ *
+ * Returns: Nonzero if the curves are identical (not just isomorphic).
+ *
+ * Use: Checks for sameness of curve parameters.
+ */
+
+int ec_sameinfop(ec_info *ei, ec_info *ej)
+{
+ return (ec_samep(ei->c, ej->c) &&
+ MP_EQ(ei->r, ej->r) && MP_EQ(ei->h, ej->h) &&
+ EC_EQ(&ei->g, &ej->g));
+}
+
/* --- @ec_freeinfo@ --- *
*
* Arguments: @ec_info *ei@ = elliptic curve information block to free
* Use: Checks an elliptic curve according to the rules in SEC1.
*/
-static int primep(mp *p, grand *gr)
-{
- int i = rabin_iters(mp_bits(p));
- rabin r;
- mp *x = MP_NEW;
-
- switch (pfilt_smallfactor(p)) {
- case PGEN_DONE: return (1);
- case PGEN_FAIL: return (0);
- }
- rabin_create(&r, p);
- while (i) {
- x = mprand_range(x, p, gr, 0);
- if (rabin_rtest(&r, x) == PGEN_FAIL)
- break;
- i--;
- }
- MP_DROP(x);
- rabin_destroy(&r);
- return (!i);
-}
-
static int primeeltp(mp *x, field *f)
{
return (!MP_ISNEG(x) && MP_CMP(x, <, f->m));
/* --- Check %$p$% is an odd prime --- */
- if (!primep(f->m, gr)) return ("p not prime");
+ if (!pgen_primep(f->m, gr)) return ("p not prime");
/* --- Check %$a$%, %$b$%, %$G_x$% and %$G_y$% are in %$[0, p)$% --- */
/* --- Check %$r$% is prime --- */
- if (!primep(ei->r, gr)) return ("generator order not prime");
+ if (!pgen_primep(ei->r, gr)) return ("generator order not prime");
/* --- Check %$0 < h \le 4$% --- */
/* --- Check %$r$% is prime --- */
- if (!primep(ei->r, gr)) return ("generator order not prime");
+ if (!pgen_primep(ei->r, gr)) return ("generator order not prime");
/* --- Check %$0 < h \le 4$% --- */
projects / u / mdw / catacomb / blobdiff