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Mutual authentication

(also two-way authentication)

Mutual authentication definition

Mutual authentication is a security process where both the server and client validate each other's identities before initiating a connection. This protocol amplifies the security measures of a connection compared to conventional one-way authentication, where identity validation only happens from the server's end.

See also: network security protocols, SSL encryption, certificate authority server

Mutual authentication examples

  • Secure shell (SSH): SSH uses mutual authentication to create a secure channel between a local and remote computer.
  • Transport layer security (TLS): TLS can be configured for mutual authentication to ensure both parties in a connection are who they claim to be.
  • Virtual private networks (VPN): Some VPN protocols use mutual authentication to increase the security of the connection.

Advantages and disadvantages of mutual authentication


  • Enhanced security: By authenticating both parties, mutual authentication reduces the risk of man-in-the-middle attacks.
  • Trust: It builds a higher level of trust in the communication as both parties verify each other..


  • Complexity: Mutual authentication involves a more complex setup and management than one-way authentication.
  • Performance: The extra security checks can lead to a slight delay in establishing a connection.

Using mutual authentication

  • Use trusted certificates for authentication to avoid spoofing attacks.
  • Ensure that both parties have a system in place for managing and renewing their digital certificates.