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experiment: Generate new Ed448 signature.

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Signed-off-by: NIIBE Yutaka <gniibe@fsij.org>
This commit is contained in:
NIIBE Yutaka 2021-10-21 13:28:04 +09:00
parent b5b81005fa
commit d506ec2685
1 changed files with 69 additions and 2 deletions
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71
g10/sign.c
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@ -404,6 +404,49 @@ hash_sigversion_to_magic (gcry_md_hd_t md, const PKT_signature *sig,
}
/* Return SOS for MPI zero representation. */
static gcry_mpi_t
sos_zero (void)
{
gcry_mpi_t a;
a = gcry_mpi_set_opaque (NULL, NULL, 0);
gcry_mpi_set_flag (a, GCRYMPI_FLAG_USER2);
return a;
}
/* Return SOS for Ed448 signature. */
static gcry_mpi_t
sos_sig_448 (gcry_mpi_t r, gcry_mpi_t s)
{
gcry_mpi_t a;
unsigned char *p;
const unsigned char *p_r, *p_s;
unsigned int nbits;
p_r = gcry_mpi_get_opaque (r, &nbits);
if ((nbits+7)/8 != 57)
return NULL;
p_s = gcry_mpi_get_opaque (s, &nbits);
if ((nbits+7)/8 != 57)
return NULL;
p = xtrymalloc (1 + 57 + 57);
if (!p)
return NULL;
p[0] = 0x40;
memcpy (p+1, p_r, 57);
memcpy (p+1+57, p_s, 57);
a = gcry_mpi_set_opaque (NULL, p, 0);
gcry_mpi_set_flag (a, GCRYMPI_FLAG_USER2);
return a;
}
/* Perform the sign operation. If CACHE_NONCE is given the agent is
* advised to use that cached passphrase for the key. SIGNHINTS has
* hints so that we can do some additional checks. */
@ -509,9 +552,33 @@ do_sign (ctrl_t ctrl, PKT_public_key *pksk, PKT_signature *sig,
else if (pksk->pubkey_algo == PUBKEY_ALGO_ECDSA
|| pksk->pubkey_algo == PUBKEY_ALGO_EDDSA)
{
err = sexp_extract_param_sos (s_sigval, "r", &sig->data[0]);
gcry_mpi_t sig_r = NULL;
gcry_mpi_t sig_s = NULL;
err = sexp_extract_param_sos (s_sigval, "r", &sig_r);
if (!err)
err = sexp_extract_param_sos (s_sigval, "s", &sig->data[1]);
err = sexp_extract_param_sos (s_sigval, "s", &sig_s);
if (!err)
{
int is_ed448 = openpgp_oid_is_ed448 (pksk->pkey[0]);
if (is_ed448)
{
sig->data[0] = sos_sig_448 (sig_r, sig_s);
if (!sig->data[0])
err = gpg_error_from_syserror ();
else
sig->data[1] = sos_zero ();
mpi_release (sig_r);
mpi_release (sig_s);
}
else
{
sig->data[0] = sig_r;
sig->data[1] = sig_s;
}
}
}
else
{