| 摘要 |
Identification system for use in a system where one unit must be sure of the identity of another unit with which it communicates, the units ranging from portable scanner applications (shown), smartcards and remote car locking applications (Figs. 7-9) , to mobile telephones and high security telephone or data links. The first unit keeps a first unit current record, which it communicates to the second unit for storage, of its activities since it last connected to the second unit. These activities are random and unpredictable, e.g. a record of the bar codes that have been scanned by a scanner, or the running count of a free running clock in the first unit at the time of connection. The first unit also keeps a first unit past record, which it also communicates to the second unit for comparison, of its activities up to the time it last connected to the second unit. If the second unit sees a match between its previously stored first unit current record and the just received first unit past record, it recognises the first unit.
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