Targeted Advertising ... And Privacy Too

The Web presents a rich and powerful tool for aggregation of consumer information. A flurry of recent articles in the popular press has documented aggressive manipulation of such information by some companies for the purposes of targeted advertising. While advertisers tout the economic and social benefits of such advertising, consumer privacy groups have expressed grave concerns about its potential abuses, and called for legislative policies to protect sensitive consumer data. In this paper, we explore the notion that targeted advertising and privacy protection need not necessarily be conflicting goals. We describe some conceptually simple technical schemes that facilitate targeted advertising, but also offer protection for sensitive consumer data. Some simple proposals do not even require the use of cryptography. (As an example, we mention an existing scheme in commercial deployment.) We also consider some more sophisticated protocols offering greater assurance of privacy. These involve cryptographic constructions that may be thought of as partial, practical PIR (private information retrieval) schemes.