This book provides information on theoretically secure multiparty computation (MPC) and secret sharing, and the fascinating relationship between the two concepts.

In a data-driven society, individuals and companies encounter numerous situations where private information is an important resource. How can parties handle confidential data if they do not trust everyone involved? This text is the first to present a comprehensive treatment of unconditionally secure techniques for multiparty computation (MPC) and secret sharing. In a secure MPC, each party possesses some private data, while secret sharing provides a way for one party to spread information on a secret such that all parties together hold full information, yet no single party has all the information. The authors present basic feasibility results from the last 30 years, generalizations to arbitrary access structures using linear secret sharing, some recent techniques for efficiency improvements, and a general treatment of the theory of secret sharing, focusing on asymptotic results with interesting applications related to MPC.

Practitioners and researchers seeking a concise, accessible introduction to secure multi-party computation which quickly enables them to build practical systems or conduct further research will find this essential reading.

We generate and gather a lot of data about ourselves and others, some of it highly confidential. The collection, storage and use of this data is strictly regulated by laws, but restricting the use of data often limits the benefits which could be obtained from its analysis. Secure multi-party computation (SMC), a cryptographic technology, makes it possible to execute specific programs on confidential data while ensuring that no other sensitive information from the data is leaked. SMC has been the subject of academic study for more than 30 years, but first attempts to use it for actual computations in the early 2000s – although theoretically efficient – were initially not practicable. However, improvements in the situation have made possible the secure solving of even relatively large computational tasks. This book describes how many different computational tasks can be solved securely, yet efficiently. It describes how protocols can be combined to larger applications, and how the security-efficiency trade-offs of different components of an SMC application should be chosen. Many of the results described in this book were achieved as part of the project Usable and Efficient Secure Multi-party Computation (UaESMC), which was funded by the European Commission. The book will be of interest to all those whose work involves the secure analysis of confidential data.

This book constitutes the refereed proceedings of the 32nd Annual International Cryptology Conference, CRYPTO 2012, held in Santa Barbara, CA, USA, in August 2012. The 48 revised full papers presented were carefully reviewed and selected from 225 submissions. The volume also contains the abstracts of two invited talks. The papers are organized in topical sections on symmetric cryptosystems, secure computation, attribute-based and functional encryption, proofs systems, protocols, hash functions, composable security, privacy, leakage and side-channels, signatures, implementation analysis, black-box separation, cryptanalysis, quantum cryptography, and key encapsulation and one-way functions.

Secure Multi-Party Computation (MPC) is one of the most powerful tools developed by modern cryptography: it facilitates collaboration among mutually distrusting parties by implementing a virtual trusted party. Despite the remarkable potential of such a tool, and decades of active research in the theoretical cryptography community, it remains a relatively inaccessible and lesser-known concept outside of this field. Only a handful of resources are available to students and researchers wishing to learn more about MPC. The editors of this book have assembled a comprehensive body of basic and advanced material on MPC, authored by experts in the field. It will serve as a starting point for those interested in pursuing research related to MPC, whether they are students learning about it for the first time or researchers already working in the area. The book begins with tutorials introducing the concept of MPC and zero-knowledge proofs, an important theoretical platform where many of the concepts central to MPC were shaped. The remaining chapters deal with classical as well as recent MPC protocols, and a variety of related topics. Each chapter is self-contained and can be read independently of the others.

This volume constitutes the refereed proceedings of the 27th Annual International Cryptology Conference held in Santa Barbara, California, in August 2007. Thirty-three full papers are presented along with one important invited lecture. The papers address current foundational, theoretical, and research aspects of cryptology, cryptography, and cryptanalysis. In addition, readers will discover many advanced and emerging applications.

This book constitutes the refereed proceedings of the Third International Workshop on Coding and Cryptology, IWCC 2011, held in Qingdao, China, May 30-June 3, 2011. The 19 revised full technical papers are contributed by the invited speakers of the workshop. The papers were carefully reviewed and cover a broad range of foundational and methodological as well as applicative issues in coding and cryptology, as well as related areas such as combinatorics.

These are the proceedings of Eurocrypt 2010, the 29th in the series of Eu- pean conferences on the Theory and Application of Cryptographic Techniques. The conference was sponsored by the International Association for Cryptologic Research and held on the French Riviera, May 30–June 3, 2010. A total of 191 papers were received of which 188 were retained as valid submissions. These were each assigned to at least three Program Committee members and a total of 606 review reports were produced. The printed record of the reviews and extensive online discussions that followed would be almost as voluminous as these proceedings. In the end 35 submissions were accepted with twosubmissionpairsbeingmergedtogive33paperspresentedattheconference. The ?nal papers in these proceedings were not subject to a second review before publication and the authors are responsible for their contents. The ProgramCommittee, listed on the next page, deservesparticular thanks for all their hard work, their outstanding expertise, and their constant c- mitment to all aspects of the evaluation process. These thanks are of course extended to the very many external reviewers who took the time to help out during the evaluation process.It was also a greatpleasure to honor and welcome Moti Yung who gave the 2010 IACR Distinguished Lecture.

In the setting of multiparty computation, sets of two or more parties with p- vate inputs wish to jointly compute some (predetermined) function of their inputs. The computation should be such that the outputs received by the parties are correctly distributed, and furthermore, that the privacy of each party’s input is preserved as much as possible, even in the presence of - versarial behavior. This encompasses any distributed computing task and includes computations as simple as coin-tossing and broadcast, and as c- plex as electronic voting, electronic auctions, electronic cash schemes and anonymous transactions. The feasibility (and infeasibility) of multiparty c- putation has been extensively studied, resulting in a rather comprehensive understanding of what can and cannot be securely computed, and under what assumptions. The theory of cryptography in general, and secure multiparty computation in particular, is rich and elegant. Indeed, the mere fact that it is possible to actually achieve the aforementioned task is both surprising and intriguing.