FTPS (File Transfer Protocol Secure), also known as FTP-SSL, emerged in the 1990s as a solution to FTP’s security limitations. It maintains the familiar FTP protocol while adding a crucial security layer through SSL (Secure Sockets Layer) or TLS (Transport Layer Security) encryption.
The relationship between FTPS and FTP mirrors that of HTTPS to HTTP – it’s essentially the same protocol with encryption wrapped around it. This approach allows organizations to upgrade their security without completely abandoning their existing FTP infrastructure and knowledge base.
FTPS offers two modes of operation: Explicit FTPS (FTPES) and Implicit FTPS. Explicit mode starts as a regular FTP connection and then upgrades to encrypted communication, while Implicit mode establishes an encrypted connection from the start. Both modes encrypt the command and data channels, protecting sensitive information during transmission.
The protocol provides strong authentication through X.509 certificates and maintains compatibility with existing internet infrastructure that already supports SSL/TLS. This widespread support makes FTPS implementation relatively straightforward for system administrators.
However, FTPS can present challenges with firewalls due to its use of multiple ports and connections. Despite this limitation, FTPS represents a significant security improvement over plain FTP while preserving the protocol’s fundamental structure and commands.
