A method and device are disclosed for executing applications that involve
secure transactions and or conditional access to valuable contents and/or
services. The device includes an integrated circuit that has a central
processing unit, an internal memory, input/output connections for
external memory and connection ports for an external interface circuit
incorporated on a single chip. The internal memory includes a secured
memory area accessible to the central processing unit only. The secret
memory area contains a secret encryption key used for encryption of
sensitive data stored in the extenal memory. Preferably, the chip
includes a random number generator. A hash value is obtained from a
random number generated by the random number generator, the random number
with its hash value are encrypted with the secret key, and the encrypted
random number with its hash value are stored in the external memory. As a
result, the device has a chip that is uniquely paired with the external
memory.
