A New Threshold-Authenticated Encryption Scheme

An authenticated encryption scheme is a message recovery scheme that provides the authenticity property. In an authenticated encryption scheme, the recipients not only verify the message authentication, but they also could recover the message. In this paper, we propose a new authenticated encryption scheme based on two hard number theoretical problems: factoring and discrete logarithm. In our new scheme, t out of n signers/senders are required to sign and at the same time encrypt a message, while k out of l recipients cooperate to verify and recover the original message. We also show that our scheme is secure against some cryptographic attacks and requires reasonable number of operations in both signature/encryption and verification/decryption phases.