A method is disclosed for certificate-based authentication, in which a first subscriber authenticates himself to a second subscriber using a digital certificate associated to the first subscriber. The certificate specifies requirement(s) and the fulfillment of a requirement is ensured by a third subscriber. Within the framework of the authentication by the second subscriber, a validity condition is checked, and the certificate is classified as valid if the validity condition is fulfilled, based on the issue and/or absence of issue of the requirement(s) specified in the certificate by the third subscriber. Requirements may be used to restrict the validity of the certificate. The validity of a certificate can thereby be controlled in a simple and flexible manner without explicitly defining the validity in the certificate. The method can be used for authentication in any technical field, e.g., to authentication subscribers in the form of components of an automation system.