Application of the Central Encryption System in the Dynamic Secret Sharing Scheme (II)

In 1979, Shamir and Blakley independently proposed the concept of secret key decentralization (Shamir, A, 1979, P.612-613 & Backly, G. R, 1979), and the mechanism implementing this idea was called as the (t, n)-threshold scheme. In two schemes, one secret key (the secret key of the system) was divided into n parts (n sub-secret keys) respectively kept by n persons, and for certain integer t(t<n), it fulfills (1) in these n persons, any r ) ( t r  persons could cooperate to recovery the private key of the system; (2) any r ) ( t r  persons could offer little help to recovery the private key of the system. This idea of private key decentralization makes the private key management more safe and flexible. After the idea of the (t, n)-threshold was proposed, many scholars proposed many schemes to implement it. At present, except of the management of secret key, it has been applied in other domains of cryptology such as signature and group attestation (Du, 2009, P.21-23).