CA (certificate authority) is an important component in PKI (Public Key Infrastructure)

and its main task is to issue and sign digital certificates that can identify different users.When the private key of a CA is compromised

all the certificates that are issued by this CA would be revoked.So

keeping the private key secret is the core of the whole PKI security.The secure managing scheme for protecting the private key of a CA recommended in this article is based on threshold cryptography.By storing the private key of a CA in more than one components and by ensuring that any component of the CA is unable to reconstruct the private key

this scheme makes sure that even if some components are compromised or some system administrators betray the private key of the CA would not be leaked and the CA can still work normally in the process of generating

distributing and using the private key.