A tentative approach to constructing tamper-resistant software

So far tamper-resistance has been considered as a prop-erty such as information stored in (I device is hard to read or modify by tampering. Such tamper-resistance is quite important in many situations: superdistribution, electronic commerce systems using IC card, pay tele-vision systems with decoders containing secret values for descrambling image and so on. Tamper-resistance ensures proper operation of a program and prevents ex-traction of secret data and abuse of the program. More-over, tamper-resistance enables a vendor to enforce his own conditions upon users. A new notion of tamper-resistance is stated as follows. Tamper-resistance means a property such as informa-tion stored in a device or software is hard to read o