The name implies what the format of the returned value, a SPKI.
The support for spki as a pkcs15 format of a pubkey, is extended to
work for any algorithm not just EC pubkeys. PKCS#15 appears to allow this.
sc_pkcs15_decode_pubkey_with_param will look for a SPKI
and attempt to use it for any algorithm, including RSA.
(RSA is the null case, as there are no algorithm parameters.)
sc_pkcs15_encode_pubkey_as_spki is exported from libopensc.
pkcs15-piv.c will use sc_pkcs15_encode_pubkey_as_spki to load public keys
as SPKI for RSA and EC.
The pubkey->data is never a SPKI, it is the DER encoding of the
pubkey without the parameters. If an spki is needed, use the
sc_pkcs15_encode_pubkey_as_spki to get the DER encoding of the spki.
As in the previous set of patches, pkcs15-tool.c will output both
sc_pkcs15_decode_pubkey_with_param and its internal.
This was left for testing, and the pubkey_pem_encode should be deleted
Viktor Tarasov
Andreas Schwier
Frank Morgner