There’s no doubt that the world of SSL certificates can be highly confusing for someone who is new to the industry. One of the reasons behind this is the different formats in which SSL certificates are issued. Yes, you read that right: SSL certificates can be issued in various formats such as CER, CRT, DER, PEM, P7B, P7S, PFX, P12, etc. That’s because SSL certificates are issued with different certificate file extensions or in different file formats — such as a PKCS7 certificate or a DER certificate — based on their encoding and the information they store.