Curve25519 support.

* agent/cvt-openpgp.c (get_keygrip): Handle Curve25519.
(convert_secret_key, convert_transfer_key): Ditto.
* common/openpgp-oid.c (oidtable): Add Curve25519.
(oid_crv25519, openpgp_oid_is_crv25519): New.
* common/util.h (openpgp_oid_is_crv25519): New.
* g10/ecdh.c (pk_ecdh_encrypt_with_shared_point): Handle the case
with Montgomery curve which uses x-only coordinate.
* g10/keygen.c (gen_ecc): Handle Curve25519.
(ask_curve): Change the API and second arg is to return subkey algo.
(generate_keypair, generate_subkeypair): Follow chage of ask_curve.
* g10/keyid.c (keygrip_from_pk): Handle Curve25519.
* g10/pkglue.c (pk_encrypt): Handle Curve25519.
* g10/pubkey-enc.c (get_it): Handle the case with Montgomery curve.
* scd/app-openpgp.c (ECC_FLAG_DJB_TWEAK): New.
(send_key_attr): Work with general ECC, Ed25519, and Curve25519.
(get_public_key): Likewise.
(ecc_writekey): Handle flag_djb_tweak.

--

When libgcrypt has Curve25519, GnuPG now supports Curve25519.

1 files changed, 6 insertions, 3 deletions

diff --git a/g10/keyid.c b/g10/keyid.c
index 68990c8bd..42a5f9fe0 100644
--- a/g10/keyid.c
+++ b/g10/keyid.c
@@ -766,9 +766,12 @@ keygrip_from_pk (PKT_public_key *pk, unsigned char *array)
         else
           {
             err = gcry_sexp_build (&s_pkey, NULL,
-                                   pk->pubkey_algo == PUBKEY_ALGO_EDDSA ?
-                                   "(public-key(ecc(curve%s)(flags eddsa)(q%m)))"
-                                   : "(public-key(ecc(curve%s)(q%m)))",
+                                   pk->pubkey_algo == PUBKEY_ALGO_EDDSA?
+                                   "(public-key(ecc(curve%s)(flags eddsa)(q%m)))":
+                                   (pk->pubkey_algo == PUBKEY_ALGO_ECDH
+                                    && openpgp_oid_is_crv25519 (pk->pkey[0]))?
+                                   "(public-key(ecc(curve%s)(flags djb-tweak)(q%m)))":
+                                   "(public-key(ecc(curve%s)(q%m)))",
                                    curve, pk->pkey[1]);
             xfree (curve);
           }