ecc: Add cofactor to domain parameters.

* src/ec-context.h (mpi_ec_ctx_s): Add cofactor 'h'.
* cipher/ecc-common.h (elliptic_curve_t): Add cofactor 'h'.
(_gcry_ecc_update_curve_param): New API adding cofactor.

* cipher/ecc-curves.c (ecc_domain_parms_t): Add cofactor 'h'.
(ecc_domain_parms_t domain_parms): Add cofactors.
(_gcry_ecc_fill_in_curve, _gcry_ecc_update_curve_param)
(_gcry_ecc_get_curve, _gcry_mpi_ec_new, _gcry_ecc_get_param_sexp)
(_gcry_ecc_get_mpi): Handle cofactor.
* cipher/ecc-eddsa.c (_gcry_ecc_eddsa_genkey): Likewise.
* cipher/ecc-misc.c (_gcry_ecc_curve_free)
(_gcry_ecc_curve_copy): Likewise.
* cipher/ecc.c (nist_generate_key, ecc_generate)
(ecc_check_secret_key, ecc_sign, ecc_verify, ecc_encrypt_raw)
(ecc_decrypt_raw, _gcry_pk_ecc_get_sexp, _gcry_pubkey_spec_ecc):
Likewise.
(compute_keygrip): Handle cofactor, but skip it for its computation.
* mpi/ec.c (ec_deinit): Likewise.
* tests/t-mpi-point.c (context_param): Likewise.
(test_curve): Add cofactors.
* tests/curves.c (sample_key_1, sample_key_2): Add cofactors.
* tests/keygrip.c (key_grips): Add cofactors.
--

We keep compatibility of compute_keygrip in cipher/ecc.c.

1 files changed, 1 insertions, 0 deletions

diff --git a/src/ec-context.h b/src/ec-context.h
index 60ca7590..c8f2ad0c 100644
--- a/src/ec-context.h
+++ b/src/ec-context.h
@@ -38,6 +38,7 @@ struct mpi_ec_ctx_s
   gcry_mpi_t b;         /* Second coefficient of the Weierstrass equation.  */
   gcry_mpi_point_t G;   /* Base point (generator).  */
   gcry_mpi_t n;         /* Order of G.  */
+  gcry_mpi_t h;         /* Cofactor.  */
 
   /* The actual key.  May not be set.  */
   gcry_mpi_point_t Q;   /* Public key.   */