trong trường hợp của một thẻ thông minh dự định được sử dụng với một điện áp cung cấp từ 3-5 V, các ngưỡng tắt máy thông thường khoảng 2,3 V và 6,3 V. Những lời nói dối một chút giá trị bên ngoài phạm vi củatheo quy định của tiêu chuẩn khác nhau, | 644 The Smart Card Life Cycle delivered data sets cannot be used if any of the chips are faulty since the defective chips are no longer available. If this method is used the personalizer must always report back to the party that generated the data to inform them which chips have actually been processed. This is not necessary with the personalization methods that are presently in common use since it is easy to reproduce a faulty card. Incidentally this is also why the personalization facilities of card producers are always secure areas. Unfortunately the cryptographic procedures and security measures used in the realm of personalization are largely secret so it is not possible for us to describe any specific application. However Figure shows an example of an initialization process followed by a personalization process as seen from a cryptographic perspective. For the cryptographic protection to be effective these two production steps must take place in separate rooms using separate personnel. The illustrated procedure works as follows. During initialization a card-specific key KD is derived in a security module using a unique chip number and a master key KM . This key is sent as plaintext to the card where it is stored. Naturally a lot of other data must be written to the smart card during the initialization but generating and storing the card-specific key KD is the only cryptographically relevant step. Following this the card is personalized. This can be done immediately following the initialization but it may also be done several weeks later. The important factor is that personalization must be completely separate from initialization in order to prevent a KD that has been illicitly acquired during initialization from being used during personalization to decrypt the card-specific data. In the personalization process the personalization data that have been encrypted using a shared key are decrypted for each individual card by the security module. This is .
