A highly efficient threshold key escrow scheme based on elliptic curve cryptosystem

In this paper, the key escrow scheme balances the needs between individuals and the ones of trustees. Firstly, in order to ensure the secret of communication information, the security of this scheme is based on the difficulty of solving discrete logarithm in finite filed. At the same time, since this threshold is a status-tree based (t, n) secret sharing scheme, it holds the characteristic with more efficiency and smaller computing. Secondly, user's private key is the product of the user and KMC, and the pieces of the user's private key can be verified, so the scheme can avoid user's cheating and "subliminal attack". Thirdly, escrow agents can not get all the information of user's private key and they must be verified. Therefore this scheme effectively resists escrow agents' cheating and "early recovery". Also, it can avert the cheating of KMC (Key Management Center) as well. Finally, it solves effectively the problem of "once monitor, monitor for ever". In the same breath, it prevents too much power of government supervision agency.