An object known as an identity object comprises a public key and a private key pair and at least one certificate issued by a certificate authority that certifies that the public key of the pair is genuine. In one embodiment, this object may be used as proof of identification by using the private key to sign data provided to it or signals derived from the data. An identity object may be stored in a non-volatile memory as proof of identity, where the memory is controlled by a controller. Preferably, a housing encloses the memory and the controller.