Which protocol is primarily used for secure file transmission over the internet?

The protocol primarily used for secure file transmission over the internet is SFTP, which stands for Secure File Transfer Protocol. SFTP operates over the SSH (Secure Shell) protocol to provide a secure channel for transferring files. This means that the data being transferred is encrypted, safeguarding it against interception and unauthorized access during transit.

SFTP not only ensures the confidentiality of the data but also provides integrity checks and authenticity through the SSH protocol's robust authentication mechanisms. This makes it a preferred choice for scenarios where sensitive information is being transmitted over the internet.

In contrast, standard FTP (File Transfer Protocol) does not provide any encryption, leaving data vulnerable to eavesdropping. HTTP (Hypertext Transfer Protocol) is primarily designed for web page transfers and lacks security features unless encapsulated with HTTPS (which is a secure extension). UDP (User Datagram Protocol) is a transport layer protocol that does not establish a reliable connection and lacks built-in security for file transfer purposes. Therefore, SFTP stands out as the ideal choice for secure file transmission.