FTPS (File Transfer Protocol Secure) is an extension of the FTP protocol that adds encryption using SSL or TLS. It is used to securely transfer files between a client and a server while protecting data such as login credentials and file contents.
FTPS is based on the traditional FTP structure but adds a security layer on top of it.
Table of Contents
How FTPS works
FTPS uses the same client–server model as FTP:
- the client connects to the server
- authentication is performed using username and password or certificates
- data is transferred between the client and server
The difference is that FTPS encrypts the connection using SSL/TLS, protecting both control commands and file data during transmission.
Encryption in FTPS
FTPS secures communication by using:
- SSL (Secure Sockets Layer) or TLS (Transport Layer Security)
- encryption of login credentials
- encryption of file contents
- optional use of digital certificates for authentication
This ensures that data cannot be easily intercepted or read during transfer.
FTPS connection modes
FTPS can operate in two modes:
Explicit FTPS
- The connection starts as standard FTP
- The client explicitly requests encryption
- Commonly uses port 21
Implicit FTPS
- The connection is encrypted immediately on connection
- Commonly uses port 990
Both modes provide encryption, but explicit FTPS is more commonly used in modern systems.
FTPS vs FTP
FTPS ≠ FTP
| Feature | FTP | FTPS |
|---|---|---|
| Encryption | No | Yes (SSL/TLS) |
| Data security | None | Encrypted |
| Credentials | Plain text | Encrypted |
| Modern usage | Legacy | Secure alternative |
FTPS improves FTP by adding encryption without changing its basic structure.
FTPS vs SFTP
FTPS is often compared with SFTP, but they are different technologies:
- FTPS is FTP with SSL/TLS encryption
- SFTP is a separate protocol based on SSH
They are not compatible with each other and use different connection methods.
Practical use cases
FTPS is used for:
- secure file transfers in legacy FTP environments
- integration with systems that already support FTP infrastructure
- transferring sensitive data with encryption requirements
- business systems requiring certificate-based authentication
Practical implications
FTPS requires additional configuration compared to SFTP, including certificate setup and firewall port management.
Because it uses multiple communication channels, FTPS may require more complex firewall configuration than SSH-based alternatives.
In modern hosting environments such as mybox, SFTP is often preferred for simplicity, while FTPS may still be supported for compatibility with older systems.
Summary
FTPS is an encrypted version of FTP that uses SSL/TLS to secure file transfers. It improves the security of traditional FTP while maintaining its structure, but is more complex to configure than newer alternatives like SFTP.