دانلود کتاب طرح های به اشتراک گذاری راز مبتنی بر کد – تئوری کدگذاری ترکیبی کاربردی

A pirate wants to disclose the secret of a treasure location to his crew. To avoid that the greedy sailors compete and fight for the secret, he dissects the map of the location into several pieces, and gives a piece to each crew member. One single piece of the map is not enough to locate the treasure. Several pieces are needed to find it. This small tale is a toy example of a secret-sharing scheme. Secret-sharing schemes form one of the most important topic in Cryptography. These protocols are used in many areas, applied mathematics, computer science, engineering, etc. A secret-sharing scheme is an encryption method. A secret s is divided into n pieces called shares. Each piece has no information about the secret, but it is retrieved by a specified of combination of these pieces. Specifically, a secret-sharing scheme is called a (k, n)-threshold scheme if the following property holds. Any k out of n pieces can reach the secret s but k−1 or fewer pieces have no information about s. The k elements that are capable of recovering the secret are called minimal access elements. A central entity, called the dealer, distributes the pieces to the participants. This distribution phase constitutes the first step of the protocol. In a second step, the recovery phase, coalitions of participants can pool their respective shares, and, if they are authorized, run an algebraic algorithm to reconstruct the secret.