Which of the following is a secure file transfer protocol?

• A. FTP
• B. HTTP
• C. SFTP
• D. Telnet

Answer: (C)

Secure file transfer depends on encryption and strong authentication to protect both credentials and data in transit. SFTP achieves this by running over SSH, which creates an encrypted channel for all commands and data. Because everything is encrypted, eavesdroppers can’t read usernames, passwords, or the file contents, and the transfer is protected against tampering and impersonation. FTP, by comparison, sends credentials and data in plaintext, making it insecure. Telnet also transmits data in plaintext and isn’t designed for secure file transfer. HTTP isn’t a dedicated secure file transfer protocol (though it can be secured with HTTPS, it’s not the standard for file transfer). So the secure file transfer protocol here is SFTP.