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Which protocol is primarily used for secure file transfer over the internet?
HTTP
FTP
SFTP
SMTP
SFTP
SFTP (SSH File Transfer Protocol) is a secure version of the File Transfer Protocol that runs over the SSH (Secure Shell) protocol. It encrypts both commands and data, preventing passwords and sensitive information from being transmitted in plaintext over the network.
IETF RFC 4253 (SSH Transport Layer Protocol)
SFTP (SSH File Transfer Protocol) is a secure version of the File Transfer Protocol that runs over the SSH (Secure Shell) protocol. It encrypts both commands and data, preventing passwords and sensitive information from being transmitted in plaintext over the network.
Security=Authentication+Encryption
SFTP operates by establishing a secure channel between the client and server using the SSH-2 protocol. All data transmitted is encrypted using symmetric encryption (e.g., AES) for the payload and asymmetric encryption (e.g., RSA or Diffie-Hellman) for the initial handshake and key exchange, ensuring data confidentiality and integrity.
SFTP provides full file system functionality, unlike older secure protocols.
It uses port 22 by default, which is the standard SSH port.
Unlike FTP, SFTP encrypts the entire session, including authentication credentials.
It supports file permissions and attribute manipulation.
High security due to mandatory encryption.
Single port requirement simplifies firewall configuration.
No separate control and data channels, reducing connectivity complexity.
Higher overhead due to encryption/decryption cycles.
Performance might be slower than FTP on low-end hardware due to CPU intensive encryption.
Secure remote server administration.
Automated enterprise file transfers.
Cloud storage synchronization.
| Feature | FTP | SFTP |
|---|---|---|
Encryption | No (Plaintext) | Yes (SSH encrypted) |
Port Requirement | Multiple ports | Single port |
FTP (File Transfer Protocol) is inherently insecure as it transmits data in plaintext.
HTTP is primarily for web page delivery, not dedicated secure file transfer.
SMTP is a protocol for electronic mail transmission, not file transfer.
C is correct тАФ SFTP is the primary protocol used for secure file transfer because it wraps file transfer operations within an encrypted SSH session.
In competitive exams, always distinguish between FTPS (FTP over SSL/TLS) and SFTP (FTP over SSH); they are different protocols despite both being secure.