How Secure Shell Works (SSH)
SSH (Secure Shell) is a cryptographic network protocol used to securely connect to remote systems over an unsecured network. It’s commonly used for managing servers, accessing network devices, and transferring files securely. Here’s a simple breakdown of how it works: 1. Client and Server Client: The system trying to access another system remotely. Usually, you run an SSH client (like ssh on Unix/Linux or PuTTY on Windows). Server: The remote system that the client wants to connect to, which runs an SSH server (like sshd on Unix/Linux). 2. Initiating the Connection When you try to connect to a remote system using SSH, the client sends a request to the SSH server on a specific port (usually port 22). The server then responds by sending its public key to the client. 3. Key Exchange and Authentication Key Exchange: The client and server exchange encryption keys to establish a secure communication channel. They use algorithms like Diffie-Hellman or Elliptic Curve Diffie-Hellman (ECDH) for this. This ensures that even if someone is eavesdropping on the connection, they won’t be able to decrypt the data. ...