Secure multi-party computation provides a wide array of protocols for mutually distrustful parties be able to securely evaluate functions of private inputs. Within recent years, many such protocols have been proposed representing a plethora of strategies to securely and efficiently handle such computation. These protocols have become increasingly efficient, but their performance still is impractical in many settings. We propose new approaches to some of these problems which are either more efficient than previous works within the same security models or offer better security guarantees with comparable efficiency. The goals of this research are to improve efficiency and security of secure multi-party protocols and explore the application of such approaches to novel threat scenarios. Some of the novel optimizations employed are dynamically switching domains of shared secrets, asymmetric computations, and advantageous functional transformations, among others. Specifically, this work presents a novel combination of Shamir and Additive secret sharing to be used in parallel which allows for the transformation of efficient protocols secure against passive adversaries to be secure against active adversaries. From this set of primitives we propose the construction of a comparison protocol which can be implemented under that approach with a complexity which is more efficient than other recent works for common domains of interest. Finally, we present a system which addresses a critical security threat for the protection and obfuscation of information which may be of high consequence.

翻译：安全多方计算为互不信任的各方提供了一系列协议，使其能够安全地计算私有输入的函数。近年来，许多此类协议被提出，代表了处理此类计算安全且高效的各种策略。这些协议已变得越来越高效，但其性能在许多场景下仍不切实际。我们针对其中一些问题提出了新方法，这些方法在同安全模型下比以往工作更高效，或在效率相当的前提下提供更优的安全保证。本研究的目标是提高安全多方协议的安全性和效率，并探索将这些方法应用于新型威胁场景。其中采用的一些新颖优化包括动态切换共享秘密的域、非对称计算以及有利的函数变换等。具体而言，本工作提出了一种结合 Shamir 和加法秘密共享的并行使用方式，使得针对被动敌手的高效协议能够转化为针对主动敌手的安全协议。基于这一组原语，我们提出了一个比较协议的构建方案，该协议可在该方法下实现，并且在常用感兴趣域中的复杂度优于近期其他工作。最后，我们提出了一套系统，用于应对可能造成严重后果的信息保护与混淆中的关键安全威胁。