Add cyclic group abstraction, with test code. Separate off exponentation

[u/mdw/catacomb] / dh-param.c

diff --git a/dh-param.c b/dh-param.c
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+/* -*-c-*-
+ *
+ * $Id: dh-param.c,v 1.1 2004/04/01 12:50:09 mdw Exp $
+ *
+ * Reading Diffie-Hellman parameters
+ *
+ * (c) 2004 Straylight/Edgeware
+ */
+
+/*----- Licensing notice --------------------------------------------------* 
+ *
+ * This file is part of Catacomb.
+ *
+ * Catacomb is free software; you can redistribute it and/or modify
+ * 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: dh-param.c,v $
+ * Revision 1.1  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.)
+ *
+ */
+
+/*----- Header files ------------------------------------------------------*/
+
+#include "dh.h"
+#include "ptab.h"
+
+/*----- Main code ---------------------------------------------------------*/
+
+/* --- @dh_parse@ --- *
+ *
+ * Arguments:  @qd_parse *qd@ = parser context
+ *             @dh_param *dp@ = parameters to fill in
+ *
+ * Returns:    Zero if OK, nonzero on error.
+ *
+ * Use:                Parses a prime group string.  This is either one of the
+ *             standard group strings, or a %$p$%, %$q$%, %$g$% triple
+ *             separated by commas.
+ */
+
+static void getinfo(dh_param *dp, pdata *pd)
+  { dp->p = &pd->p; dp->q = &pd->q; dp->g = &pd->g; }
+
+int dh_parse(qd_parse *qd, dh_param *dp)
+{
+  mp *p = MP_NEW, *q = MP_NEW, *g = MP_NEW;
+  const pentry *pe;
+
+  for (pe = ptab; pe->name; pe++) {
+    if (qd_enum(qd, pe->name) >= 0) {
+      getinfo(dp, pe->data);
+      goto found;
+    }
+  }
+  if ((p = qd_getmp(qd)) == 0) goto fail;
+  qd_delim(qd, ','); if ((q = qd_getmp(qd)) == 0) goto fail;
+  qd_delim(qd, ','); if ((g = qd_getmp(qd)) == 0) goto fail;
+  dp->p = p; dp->q = q; dp->g = g;
+found:
+  return (0);
+
+fail:
+  mp_drop(p); mp_drop(q); mp_drop(g);
+  return (-1);
+}
+
+/*----- Test rig ----------------------------------------------------------*/
+
+#ifdef TEST_RIG
+
+#include "fibrand.h"
+
+int main(void)
+{
+  const pentry *pe;
+  const char *e;
+  int ok = 1;
+  grand *gr;
+
+  gr = fibrand_create(0);
+  fputs("checking standard prime fields: ", stdout);
+  for (pe = ptab; pe->name; pe++) {
+    dh_param dp;
+    group *g;
+    getinfo(&dp, pe->data);
+    g = group_prime(&dp);
+    e = G_CHECK(g, gr);
+    G_DESTROYGROUP(g);
+    dh_paramfree(&dp);
+    if (e) {
+      fprintf(stderr, "\n*** group %s fails: %s\n", pe->name, e);
+      ok = 0;
+    }
+    putchar('.');
+    fflush(stdout);
+  }
+  gr->ops->destroy(gr);
+  fputs(ok ? " ok\n" : " failed\n", stdout);
+  return (!ok);
+}
+
+#endif
+
+/*----- That's all, folks -------------------------------------------------*/