The invention provides a cryptographic apparatus which may be "personalized" to its owner. The apparatus may be utilized by its owner to identify himself to an external computer system, to perform various financial transactions with an external system, and to provide various kinds of credentials to an external system. The apparatus, in one embodiment, is separable into a cryptographic device, packaged in a tamper resistant housing, and a personal terminal device. The cryptographic device includes interface circuitry to permit information exchange with the external system, a memory device for storage of data necessary to allow identification of the owner, and control logic for controlling the exchange of data with the external system to identify the owner. Certain data which must be utilized to perform the identification information exchange is stored in the memory device in encrypted form. The decryption of this data requires the entry of a secret ID, known to the owner.
The personal terminal device includes a data entry capability to allow the owner to enter his secret ID. Certain embodiments of the personal terminal device include data display capability to provide transaction information to the owner. Other embodiments include memory devices and a processor to allow storage and manipulation of relatively unsecured data of the owner.