Difference between FTP and SFTP?

[utkarsh]

Hi,

What is the difference between FTP and SFTP? I read about it online and have two question:

1. I understand that SFTP is secure FTP but what is secured?

2. Having Unix installed on mainframes is first condition to use SFTP? Is that correct?

[Robert Sample]

1. SFTP stands for Secure File Transfer Protocol and is based on using the Unix Secure Shell. Unlike FTP, SFTP uses a single channel for both data and control information, and that channel is encrypted.

2. Since SFTP is based upon a shell, you -- by definition -- must be using Unix System Services in order to SFTP. This is not a concern since every z/OS system has required use of Unix System Services for quite a few years.

Your post did not mention FTPS (FTP secure socket layer) which is a different protocol to provide security for communications between computers. SSL (secure socket layer) has been replaced by TLS (transport layer security), which allows two computers to negotiate the level of encryption used for their FTP connection. This encryption is established before any data flows over the data channel.

[utkarsh]

Thank you so much, Robert.