Add EVP_PKEY documentation.

Document EVP_PKEY_id() and EVP_PKEY_base_id().

Reviewed-by: Viktor Dukhovni <viktor@openssl.org>
This commit is contained in:
Dr. Stephen Henson 2016-03-13 15:49:09 +00:00
parent e7c8cafab8
commit b36a2efd55

View File

@ -6,7 +6,7 @@ EVP_PKEY_set1_RSA, EVP_PKEY_set1_DSA, EVP_PKEY_set1_DH, EVP_PKEY_set1_EC_KEY,
EVP_PKEY_get1_RSA, EVP_PKEY_get1_DSA, EVP_PKEY_get1_DH, EVP_PKEY_get1_EC_KEY,
EVP_PKEY_get0_RSA, EVP_PKEY_get0_DSA, EVP_PKEY_get0_DH, EVP_PKEY_get0_EC_KEY,
EVP_PKEY_assign_RSA, EVP_PKEY_assign_DSA, EVP_PKEY_assign_DH, EVP_PKEY_assign_EC_KEY,
EVP_PKEY_type - EVP_PKEY assignment functions.
EVP_PKEY_type, EVP_PKEY_id, EVP_PKEY_base_id - EVP_PKEY assignment functions.
=head1 SYNOPSIS
@ -32,6 +32,8 @@ EVP_PKEY_type - EVP_PKEY assignment functions.
int EVP_PKEY_assign_DH(EVP_PKEY *pkey,DH *key);
int EVP_PKEY_assign_EC_KEY(EVP_PKEY *pkey,EC_KEY *key);
int EVP_PKEY_id(const EVP_PKEY *pkey);
int EVP_PKEY_base_id(const EVP_PKEY *pkey);
int EVP_PKEY_type(int type);
=head1 DESCRIPTION
@ -54,11 +56,18 @@ and EVP_PKEY_assign_EC_KEY() also set the referenced key to B<key>
however these use the supplied B<key> internally and so B<key>
will be freed when the parent B<pkey> is freed.
EVP_PKEY_type() returns the type of key corresponding to the value
B<type>. The type of a key can be obtained with
EVP_PKEY_type(pkey->type). The return value will be EVP_PKEY_RSA,
EVP_PKEY_DSA, EVP_PKEY_DH or EVP_PKEY_EC for the corresponding
key types or NID_undef if the key type is unassigned.
EVP_PKEY_base_id() returns the type of B<pkey>. For example
an RSA key will return B<EVP_PKEY_RSA>.
EVP_PKEY_id() returns the actual OID associated with B<pkey>. Historically keys
using the same algorithm could use different OIDs. For example an RSA key could
use the OIDs corresponding to the NIDs B<NID_rsaEncryption> (equivalent to
B<EVP_PKEY_RSA) or B<NID_rsa> (equivalent to B<EVP_PKEY_RSA2>). The use of
alternative non-standard OIDs is now rare so B<EVP_PKEY_RSA2> et al are not
often seen in practice.
EVP_PKEY_type() returns the underlying type of the NID B<type>. For example
EVP_PKEY_type(EVP_PKEY_RSA2) will return B<EVP_PKEY_RSA>.
=head1 NOTES
@ -69,24 +78,31 @@ freed as well as B<pkey>.
EVP_PKEY_assign_RSA(), EVP_PKEY_assign_DSA(), EVP_PKEY_assign_DH()
and EVP_PKEY_assign_EC_KEY() are implemented as macros.
Most applications wishing to know a key type will simply call
EVP_PKEY_base_id() and will not care about the actual type:
which will be identical in almost all cases.
Previous versions of this document suggested using EVP_PKEY_type(pkey->type)
to determine the type of a key. Since B<EVP_PKEY> is now opaque this
is no longer possible: the equivalent is EVP_PKEY_base_id(pkey).
=head1 RETURN VALUES
EVP_PKEY_set1_RSA(), EVP_PKEY_set1_DSA(), EVP_PKEY_set1_DH() and
EVP_PKEY_set1_EC_KEY() return 1 for success or 0 for failure.
EVP_PKEY_get1_RSA(), EVP_PKEY_get1_DSA(), EVP_PKEY_get1_DH() and
EVP_PKEY_get1_EC_KEY() return the referenced key or B<NULL> if
EVP_PKEY_get1_EC_KEY() return the referenced key or B<NULL> if
an error occurred.
EVP_PKEY_assign_RSA(), EVP_PKEY_assign_DSA(), EVP_PKEY_assign_DH()
and EVP_PKEY_assign_EC_KEY() return 1 for success and 0 for failure.
EVP_PKEY_base_id(), EVP_PKEY_id() and EVP_PKEY_type() return a key
type or B<NID_undef> (equivalently B<EVP_PKEY_NONE>) on error.
=head1 SEE ALSO
L<EVP_PKEY_new(3)>
=head1 HISTORY
TBA
=cut