Basic Research for Realizing and Applying the Key Predistribution System

在大型复杂的现代开放式网络系统中，密码学是与未事先给定的伙伴进行安全通信的重要手段。然而，由于公共密钥加密在实际应用中仍然占主导地位，因此最大的问题是如何事先在合作伙伴之间共享公共密钥。最近提出的密钥预分配系统（KPS）的概念是解决这一问题的一种新的候选技术，本研究项目从1987年至1988年财政年度进行，（1）利用现有的电子技术验证KPS的可实现性，（2）确认KPS应用于各种信息系统的基础。目标（1）的主要结果是KPS的一种实现方案称为线性方案是有效和安全地使用IC卡实现。这一结论是基于一个深入的理论和建设性和实验研究的核心部分的算法，每个参与者在KPS。特别是，我们对一种单向随机函数的结构获得了许多有价值的见解，该函数将每个参与者的名字转换为长向量。目标（2）的主要结果包括KPS支持的任何大型网络都可以使用任何公钥体制的任何功能，KPS可以实现单向密码通信等。我们相信，线性方案将是一个非常实用和有用的工具，感测网络，通过检查的计划，建设一个原型KPS组成的IC卡为每个参与者，接口设备的IC卡和非密码通信设备，和设备的管理中心。基于这些结果开发实用的KPS将是一个强烈推荐的研究主题。

In large and complicated modern open network systems, cryptography can be a significant means for secure communication with partners which are not given a priori. However, since the common-key cryptography is still dominant for practical purposes, the largest problem has been how to share a common key among the partners beforehand. Recently proposed notion of Key Predistribution System (KPS) is a novel candidate technology to remove the problem.This research project has been performed from 1987 to 1988 fiscal year, (1) to verify the realizability of KPS by the use of presently available electronics technology and (2) to confirm the basis of applications of KPS to various information systems. The main result for goal(l) is that a kind of realization scheme of KPS called the linear scheme is efficiently and securely realizable using IC cards. This conclusion is based on a deep theoretical and constructive and experimental study of the central part of the algorithm for each participant in a KPS. In particular we obtained a number of valuable insights into the structure of a kind of one-way random function which transforms the name of each participant into a long vector. The main results for goal(2) include demonstrations of the facts that any function of any common-key system can be utilized in any large network supported by KPS, and that KPS can realize one-way cryptographic communication, and so on. Moreover, we have been convinced that the linear scheme will be a very practical and useful tool for broad-sense networks through an examination of a plan of constructing a prototype KPS consisting of IC cards for each participant, interface devices for IC cards and non-cryptographic communication equipments, and devices for the management centers. Developing practical KPS based on these results will be a strongly recommended research theme.