failed to load public key: PEM_read_bio_PUBKEY failed

[dantti]

Hi,

I tried to change the sources to use PEM_read_bio_RSA_PUBKEY or PEM_read_bio_RSAPublicKey, to no effect, I'm trying to verify the signature of this token.
Tried to change CERTIFICATE to PUBLIC KEY, but no luck, any tips?

Thanks

[Thalhammer]

A certificate is a superset of a public key. Amongst the public key, it also contains information like the issuer, expected uses and so on. You can use openssl to extract the public key like so:

openssl x509 -pubkey -noout -in google_cert.pem > pubkey.pem

The extracted public key works fine, I just tried it.

[dantti]

It indeed works, thanks, do you happen to have a code snippet to do the above without resorting to command line?

[Thalhammer]

I have not tried it, but this:
http://fm4dd.com/openssl/certpubkey.htm
and this:
https://www.openssl.org/docs/manmaster/man3/BIO_s_mem.html
Looks like a good solution.

[dantti]

Thanks, perhaps consider having this build-in? :)