According to security requirements, which service is considered secure for system operations?

The selected answer, SSH, is considered secure for system operations due to its robust encryption and authentication mechanisms. SSH, or Secure Shell, is widely used for secure remote login and other secure network services over an insecure network. It encrypts the data transmitted between the client and server, thereby protecting sensitive information like passwords and command executions from eavesdropping.

SSH also offers features such as secure file transfer and the ability to execute commands on a remote server securely. Its cryptographic protocols ensure that both the connection is encrypted and that the identity of the server is authenticated before any data exchange occurs. This makes SSH a trusted choice for secure communication in system operations.

In contrast, the other options—FTP, HTTP, and Telnet—lack these necessary security features. FTP (File Transfer Protocol) and Telnet transmit data, including sensitive information like credentials, in plaintext, making it easy for attackers to intercept and exploit that data. Similarly, HTTP, which is an unsecured version of the web protocol, does not provide encryption, leaving communication between a user's browser and web servers vulnerable to interception and attacks.

Thus, the security provided by SSH makes it the preferred choice for secure system operations.