Transport layer security (TLS) is a cryptographic protocol that provides end-to-end privacy, data integrity, and authentication between two computer applications communicating over the internet.
It is a more advanced and widely used security protocol than SSL and is essential for web browsers and applications requiring strict security for data transfer over a network. This includes emails, messaging, virtual private network (VPN) connections, web browsing sessions, remote desktop sessions, file transfers, and voice-over IP (VoIP).
What Does TLS Do?
Transport layer security (TLS) has 3 main functions: authentication, encryption, and integrity.
- Authentication: Transport layer security ensures that the entities exchanging data are not impersonating someone else; they must be who they claim to be.
- Encryption: TLS protects the information being transferred from third-party access.
- Integrity: TLS also ensures that the transferred data has not been tampered with or forged.
What is a TLS Certificate?
A transport layer security certificate is issued to applications and websites that have installed TLS on their server. It is issued by a certificate authority to the business or person who owns the domain. The TLS certificate usually contains important information about the identity of the domain owner, as well as the server‘s public key. These are essential information for validating the server’s identity.
How Does Transport Layer Security Work?
TLS works with a client-server handshake mechanism to establish a secure, authentic, and encrypted connection. This connection is established with a sequence known as the TLS handshake; when a user visits a website that uses TLS, the handshake begins between the web server and the user’s device.
The TLS handshake specifies which version of TLS and cipher suites are used, generates session keys for encrypting messages, and authenticates the server’s identity using the server’s TLS certificate.
The cipher suite is a set of algorithms that determines which session keys will be used for a particular session. The TLS uses public key cryptography to set the matching session key over an unencrypted channel.
The handshake will also handle authentication for the server to prove its identity to the client. This is done using public keys only, which are part of the TLS certificate.
Once the data is successfully encrypted and authenticated, it will be signed with a message authentication code (MAC). The recipient can verify the MAC to ensure the integrity of the data.