ecc: Fully implement Ed25519 compression in ECDSA mode.

* src/ec-context.h (mpi_ec_ctx_s): Add field FLAGS.
* mpi/ec.c (ec_p_init): Add arg FLAGS.  Change all callers to pass it.
* cipher/ecc-curves.c (point_from_keyparam): Add arg EC, parse as
 opaque mpi and use eddsa decoding depending on the flag.
(_gcry_mpi_ec_new): Rearrange to parse Q and D after knowing the
curve.

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

2 files changed, 4 insertions, 0 deletions

diff --git a/src/ec-context.h b/src/ec-context.h
index a118608e..60ca7590 100644
--- a/src/ec-context.h
+++ b/src/ec-context.h
@@ -27,6 +27,8 @@ struct mpi_ec_ctx_s
 
   enum ecc_dialects dialect;     /* The ECC dialect used with the curve.  */
 
+  int flags;                     /* Public key flags (not always used).  */
+
   unsigned int nbits;            /* Number of bits.  */
 
   /* Domain parameters.  Note that they may not all be set and if set
diff --git a/src/mpi.h b/src/mpi.h
index 15fb5423..a5d805e3 100644
--- a/src/mpi.h
+++ b/src/mpi.h
@@ -312,10 +312,12 @@ void _gcry_mpi_point_log (const char *name, mpi_point_t point, mpi_ec_t ctx);
 
 mpi_ec_t _gcry_mpi_ec_p_internal_new (enum gcry_mpi_ec_models model,
                                       enum ecc_dialects dialect,
+                                      int flags,
                                       gcry_mpi_t p, gcry_mpi_t a, gcry_mpi_t b);
 gpg_err_code_t _gcry_mpi_ec_p_new (gcry_ctx_t *r_ctx,
                                    enum gcry_mpi_ec_models model,
                                    enum ecc_dialects dialect,
+                                   int flags,
                                    gcry_mpi_t p, gcry_mpi_t a, gcry_mpi_t b);
 void _gcry_mpi_ec_free (mpi_ec_t ctx);