| 摘要 |
1,212,220. Data security. COMPUTER USAGE CO. Inc. 17 Jan., 1968 [17 Jan., 1967], No. 2604/68. Heading G4A. [Also in Division H4] Transmission of information along a communication line can be prevented by operation of a mechanically-operated lock mechanism, such operation developing an identification signal which is compared with a lock signal accompanying the information to be transmitted. In a computer system, three lock bits A, B, C (comprising the lock signal and forming part of each stored word) are applied on read-out of the associated word from memory to inputs 38, 40, 42 of a security trap (Fig. 5). Seven keyoperated locks 26 are provided for seven possible users of the computer which in this case is assumed to have only a single output terminal. Seven AND-gates 44-50 are provided with inputs so connected to the locks and the inputs 38, 40 and 42 that no AND-gate conducts so long as the lock corresponding to the identification lock bits has been operated. If such condition does not hold, a signal is passed to output device 70 to prevent transmission and/or to sound or indicate an alarm. A universal lock signal which can never give rise to alarm conditions is reserved for words which are available to all users alike. Traps may be included also between other computer components to prevent stored data being modified. In computer systems including a plurality of output terminals, each being provided with a respective lock, transmission of signals from the locks 26 to the gate 44-50 of the trap is effected on a time sharing basis (Fig. 6, not shown). Use of the invention in a multiprocessor multi-output terminal system is illustrated in Fig. 9 (not shown). In case of serial mode transmission, a serial to parallel converter (Fig. 7, not shown) may be associated with the trap. The lock signals may be associated with blocks of data instead of individual words and traps may be provided also in the input to the memory. The invention may be applied to radio or telephone communication lines. |
