Requirements and Approaches for Electronic Licenses


David Maher
Affiliation: AT&T Laboratories
Abstract: Electronic Licensing schemes have been around for several years. They have mostly been restricted to administration of software licenses over corporate local area networks. As a much wider variety of intellectual property ("IP" or "content") is distributed over public wide area networks such as the Internet, it appears that new schemes are needed to allow maintenance and control of IP rights and to support the economic value of the content. Current schemes for content distribution from IBM, EPR, AT&T and others all use a secure container paradigm, whereby content is cryptographically placed in a secure container that can be freely distributed, while the access key is independently provided to those wishing to use the IP, often after they pay. There remains the question of how the access key is distributed, and how to control use of the IP by those who have access to the key.

Whereas E-cash has been said to involve a marriage between Cryptography and Economics, Electronic Licensing involves a love-triangle comprising Cryptography, Marketing, and Economics. This is due to the fact that distribution of goods and services in a modern economy involves concepts of product bundling, multi-channel and multi-tier distribution, leasing, subscriptions, amalgamation, discounting, sampling, promotional offers, etc. Electronic distribution over networks will allow even more creative schemes to be devised, and therefore licensing approaches that overly constrain the freedom of marketing and the economic power of open markets will destroy the balance of this threesome.

Recognizing this, we examine various licensing schemes and show why we favor schemes that require a highly distributed trust model. We show that a licensing scheme with such a trust model can be implemented using the PolicyMaker system of Blaze, Feigenbaum, and Lacy. We also discuss related issues of license enforcement and payment systems.