Nippon Telegraph and Telephone Corporation

Ken Takeya

Mitsuru Shinagawa

Tadao Nagatsuma

Masami Urano

Makoto Yaita

Tomoo Fukazawa

The present invention discloses a method for randomizing a microprocessor system, such as an IC card, in order to prevent the microprocessor system from being tampered with. The method ensures that the randomized microprocessor system realizes a functionality equivalent to that of an original microprocessor system and enables easy modification of a configuration of the microprocessor system. In the context of this disclosure, to randomize a microprocessor system means to randomize a microprocessor and a program included in the microprocessor system while maintaining an equivalence of functionality realized by the microprocessor system regardless of this randomization. According to the present invention, the method for randomizing a microprocessor system performing a given functionality consists in (a) randomizing items stored in a memory in accordance with randomizing information, and (b) randomizing a microprocessor so as to allow the microprocessor to have an access to the randomized items stored in the memory. Thus, a randomized microprocessor system performing a functionality equivalent to the given functionality is generated.

Apparatus and method for modifying microprocessor system at random and maintaining equivalent functionality in spite of modification, and the same microprocessor system

An electric signal measurement apparatus using the electro-optic sampling which is capable of measuring electric signals propagating on a signal line with only a lower disturbance, in a high precision over a wide bandwidth, and economically by a relatively compact apparatus size. The apparatus has a conductor body to be set in one point contact with the signal line, and an electro-optic material which changes a birefringence according to a strength of an electric field coupled by the conductor body, and which has a sufficient thickness between the lower surface and an upper surface such that a potential at the upper surface due to the electric field coupled by the conductor body is effectively zero. A polarization detector for detecting the laser beam with a polarization changed due to a change of the birefringence of the electro-optic material can be provided within a handy type probe body to which a probe head is attached.

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Tokyo, Japan

Ken Takeya