A digital certificate is an electronic document that binds a public key to an identity, such as a website's domain name, a person or a device. It is digitally signed by a certificate authority (CA) that vouches for that binding. When your browser connects to a site over HTTPS, it checks the certificate to confirm it is talking to the real site and not an impostor. Most certificates follow the X.509 standard and contain fields such as the subject (who it is for), the issuer (which CA signed it), a serial number, validity dates, the public key, allowed key usages and the CA's signature.
Keep reading for free
Create a free StudyToCert account to read the rest of this lesson: 7 more sections, 7 key terms, a real-world example, an exam tip and self-check questions. Every lesson, lab and practice test is free with an account.