X.509

X.509 is a standard for digital certificates used in secure communications over the internet. It allows entities, like websites or individuals, to prove their identity through a certificate issued by a trusted authority. This certificate contains information such as the entity's public key, name, and the authority's signature. When you connect to a secure site (HTTPS), your browser checks the X.509 certificate to ensure it's legitimate, helping to protect against fraud and maintain privacy. Essentially, X.509 certificates establish trust in online interactions, ensuring that the parties involved are who they claim to be.