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>