SSL stands for Secure Sockets Layer. It is a protocol for establishing a secure, encrypted connection between a client and a server over the internet. The SSL protocol was developed by Netscape in the mid-1990s and is now known as TLS (Transport Layer Security), although the terms SSL and TLS are often used interchangeably.
The SSL/TLS protocol is widely used to secure online transactions, such as credit card transactions, online banking, and e-commerce. It provides authentication, confidentiality, and integrity for data exchanged between a client and a server. When an SSL/TLS connection is established, the client and server negotiate a cypher suite, which determines the encryption algorithm, message authentication code (MAC), and key exchange mechanism that will be used to secure the connection.
To use SSL/TLS, a website must have an SSL/TLS certificate, which is issued by a trusted third-party certificate authority (CA). The certificate contains information about the website, such as its domain name, and is used to authenticate the website to the client. When a client connects to a website using SSL/TLS, the website presents its SSL/TLS certificate to the client, which the client verifies against a list of trusted root certificates installed on the client’s computer. If the certificate is valid and trusted, the client and server can proceed to establish a secure connection.
SSL/TLS has evolved over the years to address security vulnerabilities and improve performance. The latest version of TLS is TLS 1.3, which was released in 2018 and offers improved security and performance over previous versions.