Different Authentication Properties and a Signcryption Scheme Revisited

We put forward the concepts of universal authentication, restrictive authentication and designated authentication. We then revisit a popular signcryption scheme using a technique similar to the one developed in Schnorr´s signature, allowing it respects the restrictive authentication property. Comparing with the modification suggested by Baek et al in 2007, which uses a zero-knowledge proof run between the recipient and the third party, our scheme saves about 1/2 cost. Besides, the security of the revisited scheme can be reduced to that of Schnorr´s signature.