The purpose of the TLS (Transport Layer Security) record layer is to ensure secure communication between client and server over a network by providing confidentiality, integrity, and authentication of data transmitted. It achieves this through encryption, message authentication codes (MACs), and cryptographic algorithms. The record layer encapsulates higher-level protocol data into records, which are then encrypted and transmitted securely. It also manages compression and fragmentation of data to optimize transmission efficiency while maintaining security.
The record protocol in SSL (Secure Sockets Layer), which is the predecessor to TLS, serves a similar purpose as the TLS record layer. It operates at the transport layer (Layer 4 of the OSI model) and is responsible for fragmenting, compressing (if enabled), encrypting, and authenticating data exchanged between the client and server. By encapsulating application data into records, the record protocol ensures that sensitive information transmitted over the network remains confidential and integral, protecting against eavesdropping and tampering.
TLS consists of two main layers: the TLS record layer and the TLS handshake protocol. The TLS record layer, as previously described, handles the encryption, authentication, and transmission of data in secure records between client and server. The TLS handshake protocol, on the other hand, is responsible for establishing the parameters of the secure connection, including negotiating cryptographic algorithms, exchanging cryptographic keys, and verifying the authenticity of the server and optionally the client. Together, these two layers ensure secure and reliable communication over the internet, facilitating the protection of sensitive information transmitted between parties.