Certificates

If you have worked with TLS certificates, you may have encountered files with the extensions .pem, .crt, and .key. You might be wondering what they are, what differences they have, and how to use them effectively. The good news is that these formats aren’t as complicated as they seem once you understand the basics: PEM, CRT, and KEY are not different certificate types — they are different ways of packaging the same data. ...

Sometimes when developers hear about public keys, private keys, and certificates, their brain goes foggy. Let’s clean that up simply. By following this post, you will understand these concepts clearly with a real-life analogy that makes them easy to remember. 1. Public Key and Private Key A key pair consists of two mathematically linked keys: where one key locks, only the other can unlock. A message encrypted with a public key can be decrypted only with the private key. A message “signed” (not really encrypted, but mathematically processed) with a private key can be verified with the public key. 1.1 Public Key → The Mailbox Imagine a mailbox in front of a house. ...