X.509 is a standard format for public key certificates, digital documents that securely associate cryptographic key pairs with identities such as websites, individuals, or organizations. However, this can also be converted to .pem files using OpenSSL.
- Save the X.509 format .cer file somewhere on your computer
- Open terminal and type the following command
$ openssl x509 -in certificate.cer -outform PEM -out certificate.pem
- Enter the password if prompted
- If successful, you should now have .pem files that can be used on your Linux servers.