Supported Transfer Protocols

Despite SSH in its name, it is designed to work over any reliable data stream, but WinSCP supports only operation over SSH, which is also by far its most common usage.

Being operated over SSH, it is secure protocol. In its basic functionally it is similar to old FTP, while having better designed advanced functionality. Unfortunately not all SFTP server implementations take advantage of the advanced features, yet.

Especially in its later versions (from 4 upwards), it is more platform independent, compared to both FTP and SCP.

Unlike SCP, for connection with an SFTP server you do not need access to shell (although some implementations may still require that).

SCP is mostly used with SSH-1. SCP is an older protocol but almost universally supported on Unix-like platforms as part of an SSH protocol suite. It is rarely supported on other platforms. SCP is a descendant of the ancient “rcp.”

The SCP protocol allows only file transfers in both directions. WinSCP is able to offer other features, implemented using common shell commands like cd, ls, pwd, rm, ln, etc. For this, WinSCP—unlike command-line SCP clients (which allow only file transfers)—requires full shell access and permission to execute other commands in addition to scp (see requirements). For access to non-UNIX servers it is necessary that the server have at least a UNIX-like shell. njuhhuhuhu

FTP, being the oldest of the three, is most widespread transfer protocol of nowadays. In its basic form it inherently insecure, sending all data (including passwords) unencrypted. There is also secure variants (FTP over TLS/SSL). FTP is functionally inferior to SFTP. Also it is less platform independent than later versions of SFTP, mainly in respect to directory listing.

The list below shows only those features which differ between the protocols, so it is not complete listing.