Abstract: The present invention provides a secure, efficient, simple and operator-independent method for generating an electronic signature, for execution by a processing unit in a mobile terminal. The method comprises the steps of receiving an electronic message, fetching a basic key from a memory area, inputting a credential from a user, generating a dynamic key based on the basic key and the credential, and generating an electronic signature for the message using the dynamic key. The invention further comprises a corresponding method for verifying the electronic signature, for execution by a verification server.