Renamed and generalized ecc_modq_random -> ecc_mod_random.

ChangeLog

 2014-09-22  Niels Möller  <nisse@lysator.liu.se>
 
+	* ecc-random.c (ecc_mod_random): Renamed, and take a const struct
+	ecc_modulo * as argument. Updated callers.
+	(ecc_modq_random): ... old name.
+
 	* ecc-mod-arith.c: New file, replacing ecc-modp.c and ecc-modq.c.
 	All functions take a struct ecc_modulo as argument.
 	(ecc_mod_add, ecc_mod_sub, ecc_mod_mul_1, ecc_mod_addmul_1)

ecc-internal.h

@@ -49,7 +49,7 @@
 #define ecc_mod_submul_1 _nettle_ecc_mod_submul_1
 #define ecc_mod_mul _nettle_ecc_mod_mul
 #define ecc_mod_sqr _nettle_ecc_mod_sqr
-#define ecc_modq_random _nettle_ecc_modq_random
+#define ecc_mod_random _nettle_ecc_mod_random
 #define ecc_mod _nettle_ecc_mod
 #define ecc_mod_inv _nettle_ecc_mod_inv
 #define ecc_hash _nettle_ecc_hash
@@ -232,8 +232,8 @@ ecc_mod_sqr (const struct ecc_modulo *m, mp_limb_t *rp,
 
 /* mod q operations. */
 void
-ecc_modq_random (const struct ecc_curve *ecc, mp_limb_t *xp,
-		 void *ctx, nettle_random_func *random, mp_limb_t *scratch);
+ecc_mod_random (const struct ecc_modulo *m, mp_limb_t *xp,
+		void *ctx, nettle_random_func *random, mp_limb_t *scratch);
 
 void
 ecc_hash (const struct ecc_curve *ecc,
@@ -287,7 +287,7 @@ curve25519_eh_to_x (mp_limb_t *xp, const mp_limb_t *p,
   (((3 << ECC_MUL_A_EH_WBITS) + 10) * (size))
 #endif
 #define ECC_ECDSA_SIGN_ITCH(size) (12*(size))
-#define ECC_MODQ_RANDOM_ITCH(size) (size)
+#define ECC_MOD_RANDOM_ITCH(size) (size)
 #define ECC_HASH_ITCH(size) (1+(size))
 
 #endif /* NETTLE_ECC_INTERNAL_H_INCLUDED */

ecc-random.c

@@ -42,56 +42,54 @@
 #include "nettle-internal.h"
 
 static int
-zero_p (const struct ecc_curve *ecc,
+zero_p (const struct ecc_modulo *m,
 	const mp_limb_t *xp)
 {
   mp_limb_t t;
   mp_size_t i;
 
-  for (i = t = 0; i < ecc->p.size; i++)
+  for (i = t = 0; i < m->size; i++)
     t |= xp[i];
 
   return t == 0;
 }
 
 static int
-ecdsa_in_range (const struct ecc_curve *ecc,
+ecdsa_in_range (const struct ecc_modulo *m,
 		const mp_limb_t *xp, mp_limb_t *scratch)
 {
   /* Check if 0 < x < q, with data independent timing. */
-  return !zero_p (ecc, xp)
-    & (mpn_sub_n (scratch, xp, ecc->q.m, ecc->p.size) != 0);
+  return !zero_p (m, xp)
+    & (mpn_sub_n (scratch, xp, m->m, m->size) != 0);
 }
 
 void
-ecc_modq_random (const struct ecc_curve *ecc, mp_limb_t *xp,
-		 void *ctx, nettle_random_func *random, mp_limb_t *scratch)
+ecc_mod_random (const struct ecc_modulo *m, mp_limb_t *xp,
+		void *ctx, nettle_random_func *random, mp_limb_t *scratch)
 {
   uint8_t *buf = (uint8_t *) scratch;
-  unsigned nbytes = (ecc->q.bit_size + 7)/8;
+  unsigned nbytes = (m->bit_size + 7)/8;
 
   /* The bytes ought to fit in the scratch area, unless we have very
      unusual limb and byte sizes. */
-  assert (nbytes <= ecc->p.size * sizeof (mp_limb_t));
+  assert (nbytes <= m->size * sizeof (mp_limb_t));
 
   do
     {
       random (ctx, nbytes, buf);
-      buf[0] &= 0xff >> (nbytes * 8 - ecc->q.bit_size);
+      buf[0] &= 0xff >> (nbytes * 8 - m->bit_size);
 
-      mpn_set_base256 (xp, ecc->p.size, buf, nbytes);
+      mpn_set_base256 (xp, m->size, buf, nbytes);
     }
-  while (!ecdsa_in_range (ecc, xp, scratch));
+  while (!ecdsa_in_range (m, xp, scratch));
 }
 
 void
 ecc_scalar_random (struct ecc_scalar *x,
 		   void *random_ctx, nettle_random_func *random)
 {
-  TMP_DECL (scratch, mp_limb_t, ECC_MODQ_RANDOM_ITCH (ECC_MAX_SIZE));
-  TMP_ALLOC (scratch, ECC_MODQ_RANDOM_ITCH (x->ecc->p.size));
+  TMP_DECL (scratch, mp_limb_t, ECC_MOD_RANDOM_ITCH (ECC_MAX_SIZE));
+  TMP_ALLOC (scratch, ECC_MOD_RANDOM_ITCH (x->ecc->q.size));
 
-  ecc_modq_random (x->ecc, x->p, random_ctx, random, scratch);
+  ecc_mod_random (&x->ecc->q, x->p, random_ctx, random, scratch);
 }
-
-

ecdsa-keygen.c

@@ -55,7 +55,7 @@ ecdsa_generate_keypair (struct ecc_point *pub,
 
   TMP_ALLOC (p, itch);
 
-  ecc_modq_random (ecc, key->p, random_ctx, random, p);
+  ecc_mod_random (&ecc->q, key->p, random_ctx, random, p);
   ecc->mul_g (ecc, p, key->p, p + 3*ecc->p.size);
   ecc->h_to_a (ecc, 0, pub->p, p, p + 3*ecc->p.size);
 }

ecdsa-sign.c

@@ -61,7 +61,7 @@ ecdsa_sign (const struct ecc_scalar *key,
      timing is still independent of the secret k finally used. */
   do
     {
-      ecc_modq_random (key->ecc, k, random_ctx, random, k + size);
+      ecc_mod_random (&key->ecc->q, k, random_ctx, random, k + size);
       ecc_ecdsa_sign (key->ecc, key->p, k, digest_length, digest,
 		   rp, sp, k + size);
       mpz_limbs_finish (signature->r, size);