ecc: New API function gcry_mpi_ec_decode_point.

* mpi/ec.c (_gcry_mpi_ec_decode_point): New.
* cipher/ecc-common.h: Move two prototypes to ...
* src/ec-context.h: here.
* src/gcrypt.h.in (gcry_mpi_ec_decode_point): New.
* src/libgcrypt.def (gcry_mpi_ec_decode_point): New.
* src/libgcrypt.vers (gcry_mpi_ec_decode_point): New.
* src/visibility.c (gcry_mpi_ec_decode_point): New.
* src/visibility.h: Add new function.
--

This new function make the use of the gcry_mpi_ec_curve_point function
possible in many contexts.  Here is a code snippet which could be used
in gpg to check a point:

static gpg_error_t
check_point (PKT_public_key *pk, gcry_mpi_t m_point)
{
  gpg_error_t err;
  char *curve;
  gcry_ctx_t gctx = NULL;
  gcry_mpi_point_t point = NULL;

  /* Get the curve name from the first OpenPGP key parameter.  */
  curve = openpgp_oid_to_str (pk->pkey[0]);
  if (!curve)
    {
      err = gpg_error_from_syserror ();
      goto leave;
    }

  point = gcry_mpi_point_new (0);
  if (!point)
    {
      err = gpg_error_from_syserror ();
      goto leave;
    }

  err = gcry_mpi_ec_new (&gctx, NULL, curve);
  if (err)
    goto leave;

  err = gcry_mpi_ec_decode_point (point, m_point, gctx);
  if (err)
    goto leave;

  if (!gcry_mpi_ec_curve_point (point, gctx))
    err = gpg_error (GPG_ERR_BAD_DATA);

 leave:
  gcry_ctx_release (gctx);
  gcry_mpi_point_release (point);
  xfree (curve);
  return err;
}

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

1 files changed, 2 insertions, 7 deletions

diff --git a/cipher/ecc-common.h b/cipher/ecc-common.h
index 4e528af8..748e6dba 100644
--- a/cipher/ecc-common.h
+++ b/cipher/ecc-common.h
@@ -89,13 +89,10 @@ elliptic_curve_t _gcry_ecc_curve_copy (elliptic_curve_t E);
 const char *_gcry_ecc_model2str (enum gcry_mpi_ec_models model);
 const char *_gcry_ecc_dialect2str (enum ecc_dialects dialect);
 gcry_mpi_t   _gcry_ecc_ec2os (gcry_mpi_t x, gcry_mpi_t y, gcry_mpi_t p);
-gcry_err_code_t _gcry_ecc_os2ec (mpi_point_t result, gcry_mpi_t value);
 
 mpi_point_t  _gcry_ecc_compute_public (mpi_point_t Q, mpi_ec_t ec,
                                        mpi_point_t G, gcry_mpi_t d);
 
-gpg_err_code_t _gcry_ecc_mont_decodepoint (gcry_mpi_t pk, mpi_ec_t ctx,
-                                           mpi_point_t result);
 
 /*-- ecc.c --*/
 
@@ -116,10 +113,8 @@ gpg_err_code_t _gcry_ecc_eddsa_encodepoint (mpi_point_t point, mpi_ec_t ctx,
                                             unsigned int *r_buflen);
 gpg_err_code_t _gcry_ecc_eddsa_ensure_compact (gcry_mpi_t value,
                                                unsigned int nbits);
-gpg_err_code_t _gcry_ecc_eddsa_decodepoint (gcry_mpi_t pk, mpi_ec_t ctx,
-                                            mpi_point_t result,
-                                            unsigned char **r_encpk,
-                                            unsigned int *r_encpklen);
+
+
 gpg_err_code_t _gcry_ecc_eddsa_compute_h_d (unsigned char **r_digest,
                                             gcry_mpi_t d, mpi_ec_t ec);