Rethinking Public Key Infrastructures and Digital Certificates: Building in Privacy

As paper-based communication and transaction mechanisms are replaced by automatedones, traditional forms of security such as photographs and handwritten signatures are becomingoutdated. Most security experts believe that digital certificates offer the best technology forsafeguarding electronic communications. They are already widely used for authenticating andencrypting email and software, and eventually will be built into any device or piece of softwarethat must be able to communicate securely. There is a serious problem, however, with thisunavoidable trend: unless drastic measures are taken, everyone will be forced to communicate viawhat will be the most pervasive electronic surveillance tool ever built. There will also be abundantopportunity for misuse of digital certificates by hackers, unscrupulous employees, governmentagencies, financial institutions, insurance companies, and so on.In this book Stefan Brands proposescryptographic building blocks for the design of digital certificates that preserve privacy withoutsacrificing security. Such certificates function in much the same way as cinema tickets or subwaytokens: anyone can establish their validity and the data they specify, but no more than that.Furthermore, different actions by the same person cannot be linked. Certificate holders have controlover what information is disclosed, and to whom. Subsets of the proposed cryptographic buildingblocks can be used in combination, allowing a cookbook approach to the design of public keyinfrastructures. Potential applications include electronic cash, electronic postage, digital rightsmanagement, pseudonyms for online chat rooms, health care information storage, electronic voting,and even electronic gambling.