Certificates

Useful for checking validity of certificates. Usually when done through something that isn't Let's Encrypt

# used to check the private key (usually ends with .key)
openssl rsa -noout -modulus -in example.com.key | openssl md5
# used to check the certificate (usually ends with .crt)
openssl x509 -noout -modulus -in example.crt | openssl md5