Add simple public-key encryption program `catcrypt'.

[u/mdw/catacomb] / ec-info.c

diff --git a/ec-info.c b/ec-info.c
index bcc0ab8..4f852c2 100644 (file)
--- a/ec-info.c
+++ b/ec-info.c
@@ -1,6 +1,6 @@
 /* -*-c-*-
  *
- * $Id: ec-info.c,v 1.3 2004/04/01 21:28:41 mdw Exp $
+ * $Id: ec-info.c,v 1.7 2004/04/17 09:58:37 mdw Exp $
  *
  * Elliptic curve information management
  *
@@ -27,26 +27,6 @@
  * MA 02111-1307, USA.
  */
 
-/*----- Revision history --------------------------------------------------* 
- *
- * $Log: ec-info.c,v $
- * Revision 1.3  2004/04/01 21:28:41  mdw
- * Normal basis support (translates to poly basis internally).  Rewrite
- * EC and prime group table generators in awk, so that they can reuse data
- * for repeated constants.
- *
- * 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.
- *
- */
-
 /*----- Header files ------------------------------------------------------*/
 
 #include "ec.h"
@@ -131,6 +111,10 @@ ec_curve *ec_curveparse(qd_parse *qd)
     default:
       goto fail;
   }
+  if (!c) {
+    qd->e = "bad curve parameters";
+    goto fail;
+  }
   if (a) MP_DROP(a);
   if (b) MP_DROP(b);
   return (c);
@@ -215,6 +199,7 @@ static void getinfo(ec_info *ei, ecdata *ed)
       abort();
   }
 
+  assert(f); assert(ei->c);
   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;
 }
@@ -248,12 +233,9 @@ int ec_infoparse(qd_parse *qd, ec_info *ei)
   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;
-    }
-  }
+  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;
@@ -390,11 +372,6 @@ static const char *primecheck(const ec_info *ei, grand *gr)
 
   if (!pgen_primep(ei->r, gr)) return ("generator order not prime");
 
-  /* --- Check %$0 < h \le 4$% --- */
-
-  if (MP_CMP(ei->h, <, MP_ONE) || MP_CMP(ei->h, >, MP_FOUR))
-    return ("cofactor out of range");
-
   /* --- Check %$h = \lfloor (\sqrt{p} + 1)^2/r \rlfoor$% --- *
    *
    * This seems to work with the approximate-sqrt in the library, but might
@@ -439,6 +416,11 @@ static const char *primecheck(const ec_info *ei, grand *gr)
   MP_DROP(x);
   if (i) return ("curve is weak");
 
+  /* --- Check %$0 < h \le 4$% --- */
+
+  if (MP_CMP(ei->h, <, MP_ONE) || MP_CMP(ei->h, >, MP_FOUR))
+    return ("cofactor out of range");
+
   /* --- Done --- */
 
   return (0);
@@ -477,11 +459,6 @@ static const char *bincheck(const ec_info *ei, grand *gr)
 
   if (!pgen_primep(ei->r, gr)) return ("generator order not prime");
 
-  /* --- Check %$0 < h \le 4$% --- */
-
-  if (MP_CMP(ei->h, <, MP_ONE) || MP_CMP(ei->h, >, MP_FOUR))
-    return ("cofactor out of range");
-
   /* --- Check %$h = \lfloor (\sqrt{2^m} + 1)^2/r \rlfoor$% --- *
    *
    * This seems to work with the approximate-sqrt in the library, but might
@@ -523,6 +500,11 @@ static const char *bincheck(const ec_info *ei, grand *gr)
   MP_DROP(x);
   if (i) return ("curve is weak");
 
+  /* --- Check %$0 < h \le 4$% --- */
+
+  if (MP_CMP(ei->h, <, MP_ONE) || MP_CMP(ei->h, >, MP_FOUR))
+    return ("cofactor out of range");
+
   /* --- Done --- */
 
   return (0);
@@ -543,29 +525,48 @@ const char *ec_checkinfo(const ec_info *ei, grand *gr)
 
 #include "fibrand.h"
 
-int main(void)
+int main(int argc, char *argv[])
 {
   const ecentry *ee;
   const char *e;
   int ok = 1;
+  int i;
   grand *gr;
 
   gr = fibrand_create(0);
-  fputs("checking standard curves: ", stdout);
-  for (ee = ectab; ee->name; ee++) {
-    ec_info ei;
-    getinfo(&ei, ee->data);
-    e = ec_checkinfo(&ei, gr);
-    ec_freeinfo(&ei);
-    if (e) {
-      fprintf(stderr, "\n*** curve %s fails: %s\n", ee->name, e);
-      ok = 0;
+  if (argc > 1) {
+    for (i = 1; i < argc; i++) {
+      ec_info ei;
+      if ((e = ec_getinfo(&ei, argv[i])) != 0)
+       fprintf(stderr, "bad curve spec `%s': %s", argv[i], e);
+      else {
+       e = ec_checkinfo(&ei, gr);
+       ec_freeinfo(&ei);
+       if (!e)
+         printf("OK %s\n", argv[i]);
+       else {
+         printf("BAD %s: %s\n", argv[i], e);
+         ok = 0;
+       }
+      }
+    }
+  } else {
+    fputs("checking standard curves: ", stdout);
+    for (ee = ectab; ee->name; ee++) {
+      ec_info ei;
+      getinfo(&ei, ee->data);
+      e = ec_checkinfo(&ei, gr);
+      ec_freeinfo(&ei);
+      if (e) {
+       fprintf(stderr, "\n*** curve %s fails: %s\n", ee->name, e);
+       ok = 0;
+      }
+      putchar('.');
+      fflush(stdout);
     }
-    putchar('.');
-    fflush(stdout);
+    fputs(ok ? " ok\n" : " failed\n", stdout);
   }
   gr->ops->destroy(gr);
-  fputs(ok ? " ok\n" : " failed\n", stdout);
   return (!ok);
 }