X.509 is a standard that defines the format of public key certificates. These certificates are used in many Internet protocols, including TLS and SSL, to provide secure communications. In cloud computing, X.509 certificates are used to secure communications between services and users.

• X.509 certificates provide a way to verify the identity of a party in a communication, improving security and trust.
• They're also used to encrypt communications, protecting data from interception and tampering.

X.509 works by providing a standard format for public key certificates. These certificates contain a public key and an identity (a hostname, or an organization, or an individual), and are either signed by a certificate authority or self-signed.

• When a certificate is presented, the recipient can verify that it is valid and that the public key belongs to the party presenting the certificate.
• This allows the recipient to trust that they're communicating with the right party and that the communication is secure.

A cloud service provider, CloudServe, uses X.509 certificates to secure communications between their cloud services and their customers. When a customer connects to a CloudServe service, the service presents an X.509 certificate. The customer can then verify the certificate and establish a secure communication channel.