PKI provides security for conversations between computers. It relies on these components to achieve its purpose:
- Digital signature (certificate): like a handwritten signature, this verifies that a message is actually from the stated source. Users, computers, routers and organisations can use digital certificates to certify their identities, so certificates thus provide authentication.
- Encryption: like seal on a soft drink bottle verifies that the contents have not been tampered with, encryption verifies that the message has not been corrupted or viewed. Encryption thus provides privacy as well as integrity to the communicating entities.