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gpg: Add X448 support.

Browse source 
* common/openpgp-oid.c (oidtable): Add X448.
(oid_x448,openpgp_oidbuf_is_x448,openpgp_oid_is_x448): New.
* common/util.h (openpgp_oid_is_x448): New.
* g10/ecdh.c (gen_k): Add handling of opaque MPI and support
endianness.
(pk_ecdh_generate_ephemeral_key): X448 requires opaque MPI.
* g10/keygen.c (gen_ecc): Add support for X448.
(ask_algo, parse_key_parameter_part): Likewise.

Signed-off-by: NIIBE Yutaka <gniibe@fsij.org>
This commit is contained in:
NIIBE Yutaka 2020-06-09 14:56:50 +09:00
parent f5bc945554
commit e9760eb9e7
4 changed files with 70 additions and 2 deletions
Download patch file Download diff file Expand all files Collapse all files

29
g10/ecdh.c
View file

@ -422,10 +422,27 @@ pk_ecdh_encrypt_with_shared_point (gcry_mpi_t shared_mpi,
static gcry_mpi_t
gen_k (unsigned nbits)
gen_k (unsigned nbits, int little_endian, int is_opaque)
{
gcry_mpi_t k;
if (is_opaque)
{
unsigned char *p;
size_t nbytes = (nbits+7)/8;
p = gcry_random_bytes_secure (nbytes, GCRY_STRONG_RANDOM);
if ((nbits % 8))
{
if (little_endian)
p[nbytes-1] &= ((1 << (nbits % 8)) - 1);
else
p[0] &= ((1 << (nbits % 8)) - 1);
}
k = gcry_mpi_set_opaque (NULL, p, nbits);
return k;
}
k = gcry_mpi_snew (nbits);
if (DBG_CRYPTO)
log_debug ("choosing a random k of %u bits\n", nbits);
@ -453,13 +470,21 @@ pk_ecdh_generate_ephemeral_key (gcry_mpi_t *pkey, gcry_mpi_t *r_k)
{
unsigned int nbits;
gcry_mpi_t k;
int is_little_endian = 0;
int require_opaque = 0;
if (openpgp_oid_is_x448 (pkey[0]))
{
is_little_endian = 1;
require_opaque = 1;
}
*r_k = NULL;
nbits = pubkey_nbits (PUBKEY_ALGO_ECDH, pkey);
if (!nbits)
return gpg_error (GPG_ERR_TOO_SHORT);
k = gen_k (nbits);
k = gen_k (nbits, is_little_endian, require_opaque);
if (!k)
BUG ();