关于（k,n）门限通信密钥分散管理系统

首先指出从Ｓｈａｎｎｏｎ信息论出发给出的门限通信密钥分散保管系统定义并不十分完善，这会将一些有价值的门限方案排除在定义之外，为了便于评价一具门限方案的好坏，给出了门限方案的新定义，并且讨论了很多方案的性能优劣以及它们之间的联系。

On (k,n) Threshold Communication Secret Key Sharing Systems

The definition of (k,n) threshold communication secret sharing systems (denoted by (k,n) TCSSS for short) is first studied. It is pointed out that the definition is not very good since it may exclude some very valuable schemes. A new definition of (k,n) TCSSS is given. This new definition can be conveniently used to evaluate any sheme of (k,n)TCSSS. Many shemes of (k,n) TCSSS that were given in recent years are discussed, and their relationships are proposed in this paper. In order to identify the legality of the persons who grasp the subcryptographic key, a general method is presented, which can be conveniently used. In the end, the multiple assignment scheme is simply considered for sharing secret.