说明：  Shamir秘密分享算法的java实现，主要是使用平面上k点可以决定k-1次方的多项式，以k点为门槛值，应用Lagrange多项式插入方法的技术，回复原多项式，再求出主密钥。
(Shamir secret sharing algorithm to achieve the java, is the use of the plane could be decided k k-1 power of the polynomial, a k-value of the threshold, Application of Lagrange polynomial method of technology insertion to restore the original polynomial, then calculated the main key.)