I have two .pem files(certificate and RSA private key) of a certificate. And I am fetching a X509 openSSL certificate object from server. How should I compare this two certificate to make sure they are same or different?
DER representation of the certificates should be the same. Either compare on binary level that they are the same (byte by byte or do SHA1 of each and compare hashes), or parse them and compare serial number, issuer and public key.