Secure Sockets Layer in the context of HTTPS

Netscape Communications Corporation (originally Mosaic Communications Corporation) was an American independent computer services company with headquarters in Mountain View, California, and then Dulles, Virginia. Its Netscape web browser was once dominant but lost to Internet Explorer and other competitors in the first browser war, with its market share falling from more than 90 percent in the mid-1990s to less than one percent in 2006. An early Netscape employee, Brendan Eich, created the JavaScript programming language, the most widely used language for client-side scripting of web pages. A founding engineer of Netscape, Lou Montulli, created HTTP cookies. The company also developed SSL which was used for securing online communications and was later renamed to TLS.

Netscape stock traded from 1995 until 1999 when the company was acquired by AOL in a pooling-of-interests transaction ultimately worth US$10 billion. In February 1998, approximately one year before its acquisition by AOL, Netscape released the source code for its browser and created the Mozilla Organization to coordinate future development of its product. The Mozilla Organization rewrote the entire browser's source code based on the Gecko rendering engine, and all future Netscape releases were based on this rewritten code. When AOL scaled back its involvement with Mozilla Organization in the early 2000s, the Organization proceeded to establish the Mozilla Foundation in July 2003 to ensure its continued independence with financial and other assistance from AOL. The Gecko engine is used to power the Mozilla Foundation's Firefox browser.

In cryptography, a public key certificate, also known as a digital certificate or identity certificate, is an electronic document used to prove the validity of a public key. The certificate includes the public key and information about it, information about the identity of its owner (called the subject), and the digital signature of an entity that has verified the certificate's contents (called the issuer). If the device examining the certificate trusts the issuer and finds the signature to be a valid signature of that issuer, then it can use the included public key to communicate securely with the certificate's subject. In email encryption, code signing, and e-signature systems, a certificate's subject is typically a person or organization. However, in Transport Layer Security (TLS) a certificate's subject is typically a computer or other device, though TLS certificates may identify organizations or individuals in addition to their core role in identifying devices. TLS, sometimes called by its older name Secure Sockets Layer (SSL), is notable for being a part of HTTPS, a protocol for securely browsing the web.

In a typical public-key infrastructure (PKI) scheme, the certificate issuer is a certificate authority (CA), usually a company that charges customers a fee to issue certificates for them. By contrast, in a web of trust scheme, individuals sign each other's keys directly, in a format that performs a similar function to a public key certificate. In case of key compromise, a certificate may need to be revoked.