How do TCP and TLS relate to each other? What problem does TLS solve?

TCP (Transmission Control Protocol) is a transport protocol that provides reliable, ordered, and checked delivery of data between two nodes in a network.

TLS (Transport Layer Security) is a cryptographic protocol that operates over TCP and ensures data transmission security: encryption, authentication, and integrity.

Relationship:

• TCP is responsible for error-free and correctly ordered data delivery.
• TLS uses TCP as a transport layer and adds protection against eavesdropping, impersonation, and man-in-the-middle attacks.

The problem TLS solves:

• Without TLS, data is transmitted in plain text, allowing attackers to intercept and modify information.
• TLS encrypts data, guarantees that the server and client are who they claim to be (authentication), and checks message integrity.

Thus, TLS provides secure communication over a reliable but unprotected TCP.