Signcryption scheme with threshold shared unsigncryption preventing malicious receivers

A new signcryption scheme with (t, n) shared unsigncryption based on the discrete logarithm is proposed, which is the integration of the signcryption scheme of Jung et al. (2001) and the Shamir (1979) secret sharing scheme. In this scheme, any t of n receivers can unsigncrypt the message and any t-1 or fewer receivers can not unsigncrypt the message. As compared to Hsu and Wu's authenticated encryption scheme with (t, n) shared verification, the proposed scheme has the following advantages: it is more efficient for signcryption; it can prevent malicious receivers from cheating others.