ecc: Require "eddsa" flag for curve Ed25519.

* src/cipher.h (PUBKEY_FLAG_ECDSA): Remove.
* cipher/pubkey-util.c (_gcry_pk_util_parse_flaglist): Remove "ecdsa".
* cipher/ecc.c (ecc_generate, ecc_sign, ecc_verify): Require "eddsa" flag.
* cipher/ecc-misc.c (_gcry_ecc_compute_public): Depend "eddsa" flag.
* tests/benchmark.c, tests/keygen.c, tests/pubkey.c
* tests/t-ed25519.c, tests/t-mpi-point.c: Adjust for changed flags.
--

This changes make using ECDSA signatures the default for all curves.
If another signing algorithm is to be used, the corresponding flag
needs to be given.  In particular the flags "eddsa" is now always
required with curve Ed25519 to comply with the specs.  This change
makes the code better readable by not assuming a certain signature
algorithm depending on the curve.

Signed-off-by: Werner Koch <wk@gnupg.org>

1 files changed, 12 insertions, 29 deletions

diff --git a/cipher/ecc.c b/cipher/ecc.c
index 8bc8ea6c..5578e052 100644
--- a/cipher/ecc.c
+++ b/cipher/ecc.c
@@ -404,7 +404,6 @@ ecc_generate (const gcry_sexp_t genparms, gcry_sexp_t *r_skey)
   gcry_mpi_t public = NULL;
   gcry_mpi_t secret = NULL;
   int flags = 0;
-  int ed25519_with_ecdsa = 0;
 
   memset (&E, 0, sizeof E);
   memset (&sk, 0, sizeof sk);
@@ -473,24 +472,10 @@ ecc_generate (const gcry_sexp_t genparms, gcry_sexp_t *r_skey)
   x = mpi_new (0);
   y = mpi_new (0);
 
-  switch (E.dialect)
-    {
-    case ECC_DIALECT_STANDARD:
-      rc = nist_generate_key (&sk, &E, ctx, random_level, nbits);
-      break;
-    case ECC_DIALECT_ED25519:
-      if ((flags & PUBKEY_FLAG_ECDSA))
-        {
-          ed25519_with_ecdsa = 1;
-          rc = nist_generate_key (&sk, &E, ctx, random_level, nbits);
-        }
-      else
-        rc = _gcry_ecc_eddsa_genkey (&sk, &E, ctx, random_level);
-      break;
-    default:
-      rc = GPG_ERR_INTERNAL;
-      break;
-    }
+  if ((flags & PUBKEY_FLAG_EDDSA))
+    rc = _gcry_ecc_eddsa_genkey (&sk, &E, ctx, random_level);
+  else
+    rc = nist_generate_key (&sk, &E, ctx, random_level, nbits);
   if (rc)
     goto leave;
 
@@ -524,15 +509,15 @@ ecc_generate (const gcry_sexp_t genparms, gcry_sexp_t *r_skey)
         goto leave;
     }
 
-  if ((flags & PUBKEY_FLAG_NOPARAM) || ed25519_with_ecdsa)
+  if ((flags & PUBKEY_FLAG_NOPARAM) || (flags & PUBKEY_FLAG_EDDSA))
     {
       rc = gcry_sexp_build
         (&curve_flags, NULL,
-         ((flags & PUBKEY_FLAG_NOPARAM) && ed25519_with_ecdsa)?
-         "(flags noparam ecdsa)" :
+         ((flags & PUBKEY_FLAG_NOPARAM) && (flags & PUBKEY_FLAG_EDDSA))?
+         "(flags noparam eddsa)" :
          ((flags & PUBKEY_FLAG_NOPARAM))?
          "(flags noparam)" :
-         "(flags ecdsa)");
+         "(flags eddsa)");
       if (rc)
         goto leave;
     }
@@ -573,8 +558,8 @@ ecc_generate (const gcry_sexp_t genparms, gcry_sexp_t *r_skey)
       log_printmpi ("ecgen result  n", sk.E.n);
       log_printmpi ("ecgen result  Q", public);
       log_printmpi ("ecgen result  d", secret);
-      if (ed25519_with_ecdsa)
-        log_debug ("ecgen result  using Ed25519/ECDSA\n");
+      if ((flags & PUBKEY_FLAG_EDDSA))
+        log_debug ("ecgen result  using Ed25519+EdDSA\n");
     }
 
  leave:
@@ -773,8 +758,7 @@ ecc_sign (gcry_sexp_t *r_sig, gcry_sexp_t s_data, gcry_sexp_t keyparms)
       log_debug ("ecc_sign   info: %s/%s%s\n",
                  _gcry_ecc_model2str (sk.E.model),
                  _gcry_ecc_dialect2str (sk.E.dialect),
-                 (sk.E.dialect == ECC_DIALECT_ED25519
-                  && (ctx.flags & PUBKEY_FLAG_ECDSA))? "ECDSA":"");
+                 (ctx.flags & PUBKEY_FLAG_EDDSA)? "+EdDSA":"");
       if (sk.E.name)
         log_debug  ("ecc_sign   name: %s\n", sk.E.name);
       log_printmpi ("ecc_sign      p", sk.E.p);
@@ -940,8 +924,7 @@ ecc_verify (gcry_sexp_t s_sig, gcry_sexp_t s_data, gcry_sexp_t s_keyparms)
       log_debug ("ecc_verify info: %s/%s%s\n",
                  _gcry_ecc_model2str (pk.E.model),
                  _gcry_ecc_dialect2str (pk.E.dialect),
-                 (pk.E.dialect == ECC_DIALECT_ED25519
-                  && !(sigflags & PUBKEY_FLAG_EDDSA))? "/ECDSA":"");
+                 (sigflags & PUBKEY_FLAG_EDDSA)? "+EdDSA":"");
       if (pk.E.name)
         log_debug  ("ecc_verify name: %s\n", pk.E.name);
       log_printmpi ("ecc_verify    p", pk.E.p);