Fig. 9 Prototype 1 for superdistribution architecture.
Fig. 9 Prototype 1 for superdistribution architecture.
Prototype 1 (Fig 9)[1] has been operating in our laboratory for three years and is available for demonstration. The S-box of Prototype 1 is connected to a NEC 9801 personal computer through an RS232C interface, but any other personal computer could be used. Prototype I was constructed when we were using the "Software Service System" name for these ideas.
Prototype II (Fig 10) is now working. We expect to fabricate the S-box chip during 1990. We further plan to demonstrate the chip and distribute a limited number of copies of it to groups that will test it. We then hope to make available sufficient technical information so that others can design and produce S-boxes with the same function and purpose as ours. These S-boxes would be coprocessors for the 68020. 68030, 80286, . and 80386 chips. The coprocessor implementation is clearly superior to the free-standing implementation because it has less overhead, would make multi-tasking possible, and is nearly invisible to users.
Prototype II does not provide encryption, nor does it physically protect the coprocessor against attacks. However, we anticipate no difficulty in using existing ASIC technology as embodied in encrypting units using established cryptographic technology to satisfy all the requirements of Section 1 of this paper.
The accounting algorithms of Prototype II are simple--simpler, even. than those of Prototype I . We are now investigating methods by which various charging methods, e. g. outright purchase and free trials, can be gotten by having a collection agent process the payment files.
Fig. 10 Prototype II for superdistribution architecture.
The extension of these methods to multi-programming is not difficult, given appropriate hardware. The MC68020 coprocessor interface has save-restore instructions for the coprocessor status, and these can be adapted to halt or resume processes within the coprocessor. It is also possible to disable interrupts in the main processor while the coprocessor is executing instructions, provided that the coprocessor can return control within a suitably short period of time. The time can be kept short because it usually requires only one general purpose coprocessor instruction to carry out the authentication required by the checking routine.
We have implemented Prototype II using the MC68020, but the interface section of Fig. 4 is the only part of the system that depends on the coprocessor interface of the MC68020. Thus our architecture can be adapted to other MPU's just by changing the interface.
Our work on Prototype II has verified that superdistribution can be achieved without a large initial investment, and reinforces our belief that a production system will be feasible in the near future. Our future plans include the following:
Although we have directed our work towards superdistribution of computer software, our architecture can be applied to other forms of digital information as well One example is music in the forms that it is recorded on digital audio tapes
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