What technology helps prevent unauthorized access using SSH keys?

Public/private key pairs are a crucial technology for preventing unauthorized access when using SSH (Secure Shell) keys. This cryptographic method relies on a pair of keys: a public key, which can be shared freely, and a private key, which is kept secret and secure. When a user attempts to connect to a server via SSH, the server verifies the user's identity by checking if the provided private key corresponds with the stored public key.

If the private key is not present on the client side or does not match the server’s record, access is denied. This ensures that only authorized users who possess the correct private key can gain access, effectively mitigating the risk of unauthorized access.

While two-factor authentication can enhance the security of SSH by adding an additional layer of verification, it is not exclusively tied to the functionality of SSH key pairs. Single-sign-on systems streamline user access across different applications but do not inherently secure SSH key usage. Encryption of SSH keys is helpful for securing the keys themselves, but it does not prevent unauthorized access unless those keys are used correctly in conjunction with a rigorous authentication process, primarily relying on the public/private key mechanism.