Debug School

Posted on

How ssh key authentication works

SSH key authentication is a method used to securely grant a user an access to a remote server or system without transmitting passwords over the network which can be intercepted. It relies on a pair of cryptographic keys: a public key and a private key.

How it works

  1. Key Generation
    : The user generates a pair of cryptographic keys - a public key and a private key. The private key is kept secure on the user's local system, while the public key can be shared freely.

  2. Public Key Placement: The user places the public key on the remote server they wish to access. Typically, this involves adding the public key to a file called authorized_keys in the .ssh directory in the user's home directory on the server.
    3*.Authentication Attempt: When the user attempts to connect to the remote server using SSH, the server sends back a challenge.
    **Key Exchange
    : The user's SSH client uses the private key to create a digital signature for the challenge and sends it back to the server.
    **Verification:* The server then verifies the signature using the public key stored in the authorized_keys file. If the signature is valid, the user is authenticated and granted access.
    5*.Connection***: Once authenticated, the user can interact with the remote server over the SSH connection as usual.

Top comments (0)