Abstract:

How to protect the security of secret keys is an important problem of security. A proactive and publicly verifiable server-assisted secret sharing scheme is proposed. The secret in this scheme is publicly verifiably shared between a user and a group of servers, and the secret reconstruction is activated by the user. Another important trait of the scheme is that it has two-side initial proactive property, that is, the shares of the user and servers will be renewed in each time period and the renewal operation is initiated by the cooperation of the user and servers. This will make the scheme very fair and make it difficult for an adversary to compromise the secret.

Key words: proactive secret sharing, publicly verifiable secret sharing, server-assisted cryptosystem