A Cryptographic Framework for the Controlled Release of Certified Data

It is usually the case that before a transaction can take place, some mutual trust must be established between the participants. On-line, doing so requires the exchange of some certified information about the participants. The easy solution is to disclose one’s identity and reveal all of one’s certificates to establish such a trust relationship. However, it is clear that such an approach is unsatisfactory from a privacy point of view. In fact, often revealing any information that uniquely corresponds to a given individual is a bad idea from the privacy point of view. In this survey paper we describe a framework where for each transaction there is a precise specification of what pieces of certified data is revealed to each participant. We show how to specify transactions in this framework, give examples of transactions that use it, and describe the cryptographic building blocks that this framework is built upon. We conclude with bibliographic notes on the state-of-the-art in this area.