Skip to main content

Home Symmetric key authentication

Symmetric key authentication

Symmetric key authentication definition

Symmetric key authentication is like having a secret password that both a sender and receiver know. They use this password to scramble (or 'encrypt') a message and then to unscramble (or 'decrypt') it.

This method is quicker than other methods that use two different passwords, but if someone else learns the secret password, it can cause a big problem for the security of the messages.

See also: authentication server, certificate-based authentication, password authentication protocol

How symmetric key encryption works:

  1. 1.The friends decide on a secret password.
  2. 2.One friend scrambles a message using the password and sends it off.
  3. 3.The other friend receives the scrambled message and uses the same password to unscramble it.
  4. 4.If they can read the message, they know it came from their friend.

Symmetric key authentication use cases:

  • Wi-Fi: When you enter a password to connect to a Wi-Fi network, you're using symmetric key authentication. The password scrambles and unscrambles the data sent over the network.
  • File Protection: When you protect a file on your computer with a password, it's usually using symmetric keys.
  • Remote Server Access (SSH): This is a way to securely access and control servers over the internet. It often uses symmetric key authentication for keeping the connection secure.
  • VPNs: These help you create a secure connection over the internet by scrambling all data sent between your device and the VPN server, often using symmetric keys.
  • Secure Websites (SSL/TLS): These technologies help secure internet traffic when you visit websites that start with 'https'. After a first greeting (or 'handshake') that uses two different keys (asymmetric authentication), they switch to a single key method (symmetric encryption) for efficiency.