Transport Layer Security (TLS) is a cryptographic protocol designed to provide communications security over a computer network. It is used to encrypt data sent over the internet to ensure that eavesdroppers and hackers are unable to see what is transmitted. TLS is mostly familiar to users through its use in secure web browsing, and in particular, the padlock icon that appears in web browsers when a secure session is established. TLS aims primarily to provide security, including privacy (confidentiality), integrity, and authenticity through the use of cryptography, such as the use of certificates, between two or more communicating computer applications. TLS is composed of two layers: the TLS record and the TLS handshake protocols. The closely related Datagram Transport Layer Security (DTLS) is a communications protocol that provides security to datagram-based applications. TLS is a proposed Internet Engineering Task Force (IETF) standard, first defined in 1999, and the current version is TLS 1.3, defined in August 2018.
TLS works by encrypting data sent between applications over the internet, ensuring the secure delivery of data over the internet, avoiding possible eavesdropping and/or alteration of the content. TLS is normally implemented on top of TCP to encrypt Application Layer protocols such as HTTP, FTP, SMTP, and IMAP, although it can also be implemented on UDP, DCCP, and SCTP as well (e.g., for VPN and SIP-based application uses) . TLS does not secure data on end systems, but it ensures the secure delivery of data over the internet, avoiding possible eavesdropping and/or alteration of the content.
TLS replaced SSL (Secure Sockets Layer) in 1999 and is an updated, more secure version of SSL. SSL is standard technology for securing an internet connection by encrypting data sent between a website and a browser (or between two servers) . HTTPS appears in the URL when a website is secured by an SSL/TLS certificate. Users can view the details of the certificate, including the issuing authority and the corporate name of the website owner, by clicking the lock symbol on the browser bar.
