Which protocol is used for securely transferring files over the internet?

Secure File Transfer Protocol, commonly known as SFTP, is specifically designed for secure file transfer over a network. It operates by providing an encrypted connection to ensure data confidentiality and integrity during the transfer process. This is crucial in a world where sensitive information is often transmitted across potentially insecure networks.

SFTP uses the Secure Shell (SSH) protocol to encrypt the data and commands that are sent over the network, protecting against eavesdropping, tampering, and other forms of attacks. This makes it a reliable choice for transferring files securely, especially in environments where data security is a priority.

In contrast, the other choices are associated with different functionalities. File Transfer Protocol (FTP) does not provide any encryption, hence making it unsuitable for secure file transfers. Simple Mail Transfer Protocol (SMTP) is used for sending emails, not for file transfer. Hypertext Transfer Protocol Secure (HTTPS) is used for secure communication over the internet, primarily for loading web pages, rather than for directly transferring files.

SFTP is, therefore, the appropriate protocol for any scenario where file transfers require security considerations.