|FTPS (also known as FTP-ES, FTP-SSL and FTP Secure) is an extension to the commonly used File Transfer Protocol (FTP) that adds support for the Transport Layer Security (TLS) and the Secure Sockets Layer (SSL) cryptographic protocols.
FTPS should not be confused with the SSH File Transfer Protocol (SFTP), an incompatible secure file transfer subsystem for the Secure Shell (SSH) protocol. It is also different from Secure FTP, the practice of tunneling FTP through an SSH connection.
The File Transfer Protocol was drafted in 1971 for use with the scientific and research network, ARPANET. Access to the ARPANET during this time was limited to a small number of military sites and universities and a narrow community of users who could operate without data security and privacy requirements within the protocol.
As the ARPANET gave way to the NSFnet and then the Internet, a broader population potentially had access to the data as it traversed increasingly longer paths from client to server. The opportunity for unauthorized third parties to eavesdrop on data transmissions increased proportionally.
In 1994, the internet browser company Netscape developed and released the application layer wrapper, Secure Sockets Layer. This protocol enabled applications to communicate across a network in a private and secure fashion, discouraging eavesdropping, tampering, and message forgery. While it could add security to any protocol that uses reliable connections, such as TCP, it was most commonly used by Netscape with HTTP to form HTTPS.
The SSL protocol was eventually applied to FTP, with a draft Request for Comments (RFC) published in late 1996. An official IANA port was registered shortly thereafter. However, the RFC was not finalized until 2005.