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, 5 insertions, 10 deletions

diff --git a/doc/gcrypt.texi b/doc/gcrypt.texi
index 9c695e02..03ace833 100644
--- a/doc/gcrypt.texi
+++ b/doc/gcrypt.texi
@@ -2251,15 +2251,10 @@ Use RSA-OAEP padding for encryption.
 @cindex PSS
 Use RSA-PSS padding for signing.
 
-@item ecdsa
-@cindex ECDSA
-Create an ECDSA public key instead of using the default key generation
-of the specified curve.
-
 @item eddsa
 @cindex EdDSA
-Use the EdDSA scheme instead of the default signature algorithm of the
-used curve.
+Use the EdDSA scheme signing instead of the default ECDSA algorithm.
+Note that the EdDSA uses a special form of the public key.
 
 @item rfc6979
 @cindex RFC6979
@@ -2854,7 +2849,7 @@ is in general not recommended.
 @example
 (genkey
   (ecc
-    (flags noparam transient-key ecdsa)))
+    (flags noparam transient-key)))
 @end example
 
 @item transient-key
@@ -2899,12 +2894,12 @@ elliptic curve key generation:
   (public-key
     (ecc
       (curve Ed25519)
-      (flags noparam)
+      (flags noparam eddsa)
       (q @var{q-value})))
   (private-key
     (ecc
       (curve Ed25519)
-      (flags noparam)
+      (flags noparam eddsa)
       (q @var{q-value})
       (d @var{d-value}))))
 @end example