A biometric authentication system , comprising: one or more inputs , for receiving biometric input signals from a user; and a biometric authentication module having one or more biometric authentication module inputs, and being configured to carry out biometric authentication of signals received at the one or more biometric authentication module inputs and generate an authentication result; characterized by further comprising: a control interface , for receiving one or more control signals from an application processor; a routing module , having a set of routing inputs and a set of routing outputs, at least one of the routing inputs being coupled to the one or more inputs and at least one of the routing outputs being coupled to the biometric authentication module, the routing module being configurable by the one or more control signals to route signals from one or more of the routing inputs to one or more of the routing outputs; and a security module , operable to determine whether a routing module configuration complies with one or more rules and, responsive to a determination that the routing module configuration does not comply with one or more of the one or more rules, generate a signal indicating that the routing module configuration is insecure. one or more inputs , for receiving biometric input signals from a user; and a biometric authentication module having one or more biometric authentication module inputs, and being configured to carry out biometric authentication of signals received at the one or more biometric authentication module inputs and generate an authentication result; characterized by further comprising: a control interface , for receiving one or more control signals from an application processor; a routing module , having a set of routing inputs and a set of routing outputs, at least one of the routing inputs being coupled to the one or more inputs and at least one of the routing outputs being coupled to the biometric authentication module, the routing module being configurable by the one or more control signals to route signals from one or more of the routing inputs to one or more of the routing outputs; and a security module , operable to determine whether a routing module configuration complies with one or more rules and, responsive to a determination that the routing module configuration does not comply with one or more of the one or more rules, generate a signal indicating that the routing module configuration is insecure. a control interface , for receiving one or more control signals from an application processor; a routing module , having a set of routing inputs and a set of routing outputs, at least one of the routing inputs being coupled to the one or more inputs and at least one of the routing outputs being coupled to the biometric authentication module, the routing module being configurable by the one or more control signals to route signals from one or more of the routing inputs to one or more of the routing outputs; and a security module , operable to determine whether a routing module configuration complies with one or more rules and, responsive to a determination that the routing module configuration does not comply with one or more of the one or more rules, generate a signal indicating that the routing module configuration is insecure. <EOS>