SFTP, or Secure File Transfer Protocol, is a secure version of the File Transfer Protocol (FTP), which is a widely-used protocol for transferring files over the internet. FTP is a simple, widely-supported protocol that allows users to upload and download files to and from a server, but it does not provide any security or encryption. SFTP adds support for SSH (Secure Shell) encryption to FTP, which helps protect the confidentiality and integrity of the data being transferred. SFTP is often used in environments where data security is important, such as in financial or healthcare applications. It is supported by most FTP client and server software, but requires that both the client and server support SSH. Unlike FTPS, which uses the older SSL/TLS protocols for encryption, SFTP uses the more modern and secure SSH protocol.