It to through keep common key change , realize evolving private key according to definite period with one-way function mainly, after guaranteeing that the present private key is let out, will not influence the signature before this period.

• 它主要是通过保持公钥不变，把私钥按照确定的时段用单向函数实现进化，保证了当前的私钥泄漏后，不会影响到这个时段之前的签名。