What is an X.509 certificate?
An X.509 certificate is a data structure that is used for identity presentation and identity verification. A certificate may be saved to a file or transmitted via a network, and also as a part of a secure network protocol, such as TLS. An X.509 certificate binds an identity to a public key using a digital signature.
Here is an example text representation of an X.509 certificate:
Certificate: Data: Version: 3 (0x2) Serial Number: ... hex bytes ... Signature Algorithm: sha256WithRSAEncryption Issuer: C = US, O = Let's Encrypt, CN = R3 Validity Not Before: Mar 4 12:43:52 2022 GMT ...