gpg: Rework ECC support and add experimental support for Ed25519.

* agent/findkey.c (key_parms_from_sexp): Add algo name "ecc".
(agent_is_dsa_key): Ditto.
(agent_is_eddsa_key): New.  Not finished, though.
* agent/pksign.c (do_encode_eddsa): New.
(agent_pksign_do): Use gcry_log_debug functions.
* agent/protect.c (agent_protect): Parse a flags parameter.
* g10/keygen.c (gpg_curve_to_oid): Move to ...
* common/openpgp-oid.c (openpgp_curve_to_oid): here and rename.
(oid_ed25519): New.
(openpgp_oid_is_ed25519): New.
(openpgp_oid_to_curve): New.
* common/t-openpgp-oid.c (test_openpgp_oid_is_ed25519): New.
* g10/build-packet.c (gpg_mpi_write): Write the length header also for
opaque MPIs.
(gpg_mpi_write_nohdr): New.
(do_key): Use gpg_mpi_write_nohdr depending on algorithm.
(do_pubkey_enc): Ditto.
* g10/ecdh.c (pk_ecdh_encrypt_with_shared_point): Use
gpg_mpi_write_nohdr.
* g10/export.c (transfer_format_to_openpgp):
* g10/keygen.c (ecckey_from_sexp): Return the error.
(gen_ecc): Repalce arg NBITS by CURVE.
(read_parameter_file): Add keywords "Key-Curve" and "Subkey-Curve".
(ask_curve): New.
(generate_keypair, generate_subkeypair): Use ask_curve.
(do_generate_keypair): Also pass curve name.
* g10/keylist.c (list_keyblock_print, list_keyblock_colon): Print
curve name.
* g10/parse-packet.c (mpi_read): Remove workaround for
Libcgrypt < 1.5.
(parse_key): Fix ECC case.  Print the curve name.
* g10/pkglue.c (mpi_from_sexp): Rename to get_mpi_from_sexp.
(pk_verify, pk_check_secret_key): Add special case for Ed25519.
* g10/seskey.c (encode_md_value): Ditto.
* g10/sign.c (do_sign, hash_for, sign_file): Ditto.
--

Be warned that this code is subject to further changes and that the
format will very likely change before a release.  There are also known
bugs and missing code.

Signed-off-by: Werner Koch <[email protected]>

1 files changed, 29 insertions, 0 deletions

diff --git a/agent/findkey.c b/agent/findkey.c
index d11f0888a..aa2c6a2c1 100644
--- a/agent/findkey.c
+++ b/agent/findkey.c
@@ -729,6 +729,11 @@ key_parms_from_sexp (gcry_sexp_t s_key, gcry_sexp_t *r_list,
       algoname = "dsa";
       elems = "pqgy";
     }
+  else if (n==3 && !memcmp (name, "ecc", 3))
+    {
+      algoname = "ecc";
+      elems = "pabgnq";
+    }
   else if (n==5 && !memcmp (name, "ecdsa", 5))
     {
       algoname = "ecdsa";
@@ -788,6 +793,8 @@ agent_is_dsa_key (gcry_sexp_t s_key)
 
   if (!strcmp (algoname, "dsa"))
     return GCRY_PK_DSA;
+  else if (!strcmp (algoname, "ecc"))
+    return GCRY_PK_ECDSA; /* FIXME: Check for the EdDSA flag.  */
   else if (!strcmp (algoname, "ecdsa"))
     return GCRY_PK_ECDSA;
   else
@@ -795,6 +802,28 @@ agent_is_dsa_key (gcry_sexp_t s_key)
 }
 
 
+/* Return true if S_KEY is an EdDSA key as used with curve Ed25519.  */
+int
+agent_is_eddsa_key (gcry_sexp_t s_key)
+{
+  char algoname[6];
+
+  if (!s_key)
+    return 0;
+
+  if (key_parms_from_sexp (s_key, NULL, algoname, sizeof algoname, NULL, 0))
+    return 0; /* Error - assume it is not an DSA key.  */
+
+  if (!strcmp (algoname, "dsa"))
+    return GCRY_PK_DSA;
+  else if (!strcmp (algoname, "ecc"))
+    return GCRY_PK_ECDSA; /* FIXME: Check for the EdDSA flag.  */
+  else if (!strcmp (algoname, "ecdsa"))
+    return GCRY_PK_ECDSA;
+  else
+    return 0;
+}
+
 
 /* Return the key for the keygrip GRIP.  The result is stored at
    RESULT.  This function extracts the key from the private key