const char *
_gcry_pk_get_curve (gcry_sexp_t key, int iterator, unsigned int *r_nbits)
{
const char *result = NULL;
gcry_pk_spec_t *spec;
gcry_sexp_t keyparms = NULL;
if (r_nbits)
*r_nbits = 0;
if (key)
{
iterator = 0;
if (spec_from_sexp (key, 0, &spec, &keyparms))
return NULL;
}
else
{
spec = spec_from_name ("ecc");
if (!spec)
return NULL;
}
if (spec->get_curve)
result = spec->get_curve (keyparms, iterator, r_nbits);
sexp_release (keyparms);
return result;
}
/*
Get the number of nbits from the public key.
Hmmm: Should we have really this function or is it better to have a
more general function to retrieve different properties of the key? */
unsigned int
_gcry_pk_get_nbits (gcry_sexp_t key)
{
gcry_pk_spec_t *spec;
gcry_sexp_t parms;
unsigned int nbits;
/* Parsing KEY might be considered too much overhead. For example
for RSA we would only need to look at P and stop parsing right
away. However, with ECC things are more complicate in that only
a curve name might be specified. Thus we need to tear the sexp
apart. */
if (spec_from_sexp (key, 0, &spec, &parms))
return 0; /* Error - 0 is a suitable indication for that. */
nbits = spec->get_nbits (parms);
sexp_release (parms);
return nbits;
}
/*
Test a key.
This may be used either for a public or a secret key to see whether
the internal structure is okay.
Returns: 0 or an errorcode.
NOTE: We currently support only secret key checking. */
gcry_err_code_t
_gcry_pk_testkey (gcry_sexp_t s_key)
{
gcry_err_code_t rc;
gcry_pk_spec_t *spec;
gcry_sexp_t keyparms;
rc = spec_from_sexp (s_key, 1, &spec, &keyparms);
if (rc)
goto leave;
if (spec->check_secret_key)
rc = spec->check_secret_key (keyparms);
else
rc = GPG_ERR_NOT_IMPLEMENTED;
leave:
sexp_release (keyparms);
return rc;
}
/*
Verify a signature.
Caller has to supply the public key pkey, the signature sig and his
hashvalue data. Public key has to be a standard public key given
as an S-Exp, sig is a S-Exp as returned from gcry_pk_sign and data
must be an S-Exp like the one in sign too. */
gcry_err_code_t
_gcry_pk_verify (gcry_sexp_t s_sig, gcry_sexp_t s_hash, gcry_sexp_t s_pkey)
{
gcry_err_code_t rc;
gcry_pk_spec_t *spec;
gcry_sexp_t keyparms;
rc = spec_from_sexp (s_pkey, 0, &spec, &keyparms);
if (rc)
goto leave;
if (spec->verify)
rc = spec->verify (s_sig, s_hash, keyparms);
else
rc = GPG_ERR_NOT_IMPLEMENTED;
leave:
sexp_release (keyparms);
return rc;
}
/*
Create a signature.
Caller has to provide a secret key as the SEXP skey and data
expressed as a SEXP list hash with only one element which should
instantly be available as a MPI. Alternatively the structure given
below may be used for S_HASH, it provides the abiliy to pass flags
to the operation; the flags defined by now are "pkcs1" which does
PKCS#1 block type 1 style padding and "pss" for PSS encoding.
Returns: 0 or an errorcode.
In case of 0 the function returns a new SEXP with the
signature value; the structure of this signature depends on the
other arguments but is always suitable to be passed to
gcry_pk_verify
s_hash = See comment for _gcry-pk_util_data_to_mpi
s_skey = <key-as-defined-in-sexp_to_key>
r_sig = (sig-val
(<algo>
(<param_name1> <mpi>)
...
(<param_namen> <mpi>))
[(hash algo)])
Note that (hash algo) in R_SIG is not used.
*/
gcry_err_code_t
_gcry_pk_sign (gcry_sexp_t *r_sig, gcry_sexp_t s_hash, gcry_sexp_t s_skey)
{
gcry_err_code_t rc;
gcry_pk_spec_t *spec;
gcry_sexp_t keyparms;
*r_sig = NULL;
rc = spec_from_sexp (s_skey, 1, &spec, &keyparms);
if (rc)
goto leave;
if (spec->sign)
rc = spec->sign (r_sig, s_hash, keyparms);
else
rc = GPG_ERR_NOT_IMPLEMENTED;
leave:
sexp_release (keyparms);
return rc;
}
/*
Do a PK decrypt operation
Caller has to provide a secret key as the SEXP skey and data in a
format as created by gcry_pk_encrypt. For historic reasons the
function returns simply an MPI as an S-expression part; this is
deprecated and the new method should be used which returns a real
S-expressionl this is selected by adding at least an empty flags
list to S_DATA.
Returns: 0 or an errorcode.
s_data = (enc-val
[(flags [raw, pkcs1, oaep])]
(<algo>
(<param_name1> <mpi>)
...
(<param_namen> <mpi>)
))
s_skey = <key-as-defined-in-sexp_to_key>
r_plain= Either an incomplete S-expression without the parentheses
or if the flags list is used (even if empty) a real S-expression:
(value PLAIN). In raw mode (or no flags given) the returned value
is to be interpreted as a signed MPI, thus it may have an extra
leading zero octet even if not included in the original data.
With pkcs1 or oaep decoding enabled the returned value is a
verbatim octet string.
*/
gcry_err_code_t
_gcry_pk_decrypt (gcry_sexp_t *r_plain, gcry_sexp_t s_data, gcry_sexp_t s_skey)
{
gcry_err_code_t rc;
gcry_pk_spec_t *spec;
gcry_sexp_t keyparms;
*r_plain = NULL;
rc = spec_from_sexp (s_skey, 1, &spec, &keyparms);
if (rc)
goto leave;
if (spec->decrypt)
rc = spec->decrypt (r_plain, s_data, keyparms);
else
rc = GPG_ERR_NOT_IMPLEMENTED;
leave:
sexp_release (keyparms);
return rc;
}
/*
Do a PK encrypt operation
Caller has to provide a public key as the SEXP pkey and data as a
SEXP with just one MPI in it. Alternatively S_DATA might be a
complex S-Expression, similar to the one used for signature
verification. This provides a flag which allows to handle PKCS#1
block type 2 padding. The function returns a sexp which may be
passed to to pk_decrypt.
Returns: 0 or an errorcode.
s_data = See comment for _gcry_pk_util_data_to_mpi
s_pkey = <key-as-defined-in-sexp_to_key>
r_ciph = (enc-val
(<algo>
(<param_name1> <mpi>)
...
(<param_namen> <mpi>)
))
*/
gcry_error_t
gcry_pk_encrypt (gcry_sexp_t *r_ciph, gcry_sexp_t s_data, gcry_sexp_t s_pkey)
{
gcry_err_code_t rc;
gcry_pk_spec_t *spec;
gcry_sexp_t keyparms;
*r_ciph = NULL;
rc = spec_from_sexp (s_pkey, 0, &spec, &keyparms);
if (rc)
goto leave;
if (spec->encrypt)
rc = spec->encrypt (r_ciph, s_data, keyparms);
else
rc = GPG_ERR_NOT_IMPLEMENTED;
leave:
gcry_sexp_release (keyparms);
return gcry_error (rc);
}
