CompTIA Security+ Get Certified Get Ahead: SY0-501 Study Guide

by Darril Gibson

Imagine that I wanted you to send some proprietary information and a working model of an invention to me. Obviously, we wouldn’t want anyone else to be able to access the information or the working model. I could send you the empty open box with a copy of the key used to lock it. You place everything in the box and then lock it with the public key I’ve sent with the box. This key can’t unlock the box, so even if other people had copies of the public key that I sent to you, they couldn’t use it to unlock the box. When I receive the box from you, I can unlock it with the only key that will unlock it—my private key. This is similar to how public and private keys are used to send encrypted data over the Internet to ensure confidentiality. The public key encrypts information. Information encrypted with a public key can only be decrypted with the matching private key. Many copies of the public key are available, but only one private key exists, and the private key always stays private. The “Encrypting HTTPS Traffic with TLS” section later in this chapter shows this process in more depth.