This is an introductory version of the widely acclaimed book that redefined how to build databases that protect the user's information. Instead of trying to store sensitive data in a tightly guarded box, the book describes simpler, faster and more secure solutions that leave the user in control of personal information. The trick to building a translucent database is scrambling the personal information in a way that only the right person can recover it. The book describes how traditional and not-so-traditional techniques can create a database that can answer questions for the right person without holding any useful information that might be abused by an insider or an attacker who manages to slip inside the fold. The abridged version of the second edition includes the six chapters that form the core of the book. All of the chapters include detailed descriptions of the algorithms and many descriptions include working code.