This tool decodes a X509 certificate that is in base64
. These certificates are usually kept in a file with .pem extension.
Decoding a certificate allows you to read all of its content, including the issuer of the certificate (the certificate authority or intermediate certificate authority that signed the certificate),
the subject (a person, organization, server or device that the certificate was issued to), the serial number, the signature, the public key of the certificate (the private key is kept by the owner of the certificate),
and some more relevant information.
If your certificate is in pkcs12 format (binary certificate with a password that contains both public and private keys) you can convert it first to a pair of public certificate and private key both in pem format