gpg: Initial support for generating Kyber subkeys.
* common/openpgpdefs.h (PUBKEY_ALGO_KY768_25519): Remove. (PUBKEY_ALGO_KY1024_448): Remove. (PUBKEY_ALGO_KYBER): New. Use them everywhere instead of the removed. * g10/build-packet.c (gpg_mpi_write_nohdr): Rename to (gpg_mpi_write_opaque_nohdr): this. Change callers. (gpg_mpi_write_opaque_32): New. (do_key): Support Kyber keys using the revised format. * g10/gpg.h (MAX_EXTERN_KEYPARM_BITS): New. * g10/parse-packet.c (read_octet_string): Add arg nbytes so support reading with a length prefix. Adjust callers. (parse_key): Parse Kyber public keys. * g10/misc.c (pubkey_get_npkey): Support Kyber. (pubkey_get_nskey): Ditto. * g10/keyid.c (pubkey_string): Support dual algorithms. (do_hash_public_key): Support Kyber. (nbits_from_pk): Ditto. (keygrip_from_pk): Return the Kyber part for the ECC+Kyber dual algo. * g10/keygen.c (struct common_gen_cb_parm_s): Add genkey_result2. Note that this callback is not yet used. (ecckey_from_sexp): Add optional arg sexp2 and use it for Kyber. Change callers. (ecckey_from_sexp): Do not leak LIST in case of an error. (common_gen): Add arg keyparms2, change callers, and support Kyber. (gen_kyber): New. (get_keysize_range): Support Kyber. (fixup_keysize): Simplify and support Kyber. (do_create): Handle Kyber. (parse_key_parameter_part): Remove algo strings "ky768" and "ky1024" and add a generic "kyber" with default parameters.
This uses a revised format which is more aligned with the usual
OpenPGP structure. A lot of things are still missing. For example
support for handling two keygrips and checking both of them in a -K
listing. There is also only ky768_bp384 as fixed algorithm for now.
No passphrase for the Kyber part of the dual algorithm is on purpose.
A test was done using
gpg --quick-gen-key pqc1 nistp256
and then running
gpg -v --quick-add-key <fingerprint> kyber
which creates a v5 subkey on a v4 primary key. A second test using
gpg --quick-gen-key pqc2 Ed448
followed by a --quick-add-key created a v5 key with a v5 subkey.
- GnuPG-bug-id: T6815