CompleteFTP supports FTP, FTPS, SFTP, SCP and SSH (from version 4.0).
FTPS is often described as FTP over an SSL connection, while SFTP is file transfer secured by SSH. SCP is an earlier form of secure copy which is also over SSH. CompleteFTP also supports SSH terminals.
The Standard Edition supports FTP, FTPS and SFTP.
Both SCP and SSH are additionally supported in the Professional Edition.