On 2022-11-10 18:35, f...@plutonium24.de wrote:
I have been using EVP_PKEY_get_raw_public_key with OpenSSL 1.1.1 without
any problems to extract a raw public key (secp521r1, NIST curve P-521).
With OpenSSL 3.0 this fails. I'm using this call to get the raw public
key and to compare it with a reference value I have and I also check
that the group name is "secp521r1".
That doesn't work in 3.0.
Quoting from
https://www.openssl.org/docs/manmaster/man3/EVP_PKEY_new.html :
<quote>
EVP_PKEY_get_raw_public_key() fills the buffer provided by pub with raw
public key data. The size of the pub buffer should be in *len on entry
to the function, and on exit *len is updated with the number of bytes
actually written. If the buffer pub is NULL then *len is populated with
the number of bytes required to hold the key. The calling application is
responsible for ensuring that the buffer is large enough to receive the
public key data. This function only works for algorithms that support
raw public keys. Currently this is: EVP_PKEY_X25519, EVP_PKEY_ED25519,
EVP_PKEY_X448 or EVP_PKEY_ED448.
</quote>
You were reading the P521 public-key previously (with 1.1.1), but in
what format was it sent you? Do you want just the bytes of the public
EC point?
-James M
