Improvements of generalization of threshold signature and authenticated encryption for group communications

Recently, Wang et al. proposed a (t, n) threshold signature scheme with (k, l) threshold shared verification and a group-oriented authenticated encryp tion scheme with (k, l) threshold shared verification. However, this articl e will show that both the schemes violate the requirement of the (k, l) thr eshold shared verification. Further, two improvements are proposed to elimi nate the pointed out security leaks inherent in the original schemes. (C) 2 002 Elsevier Science B.V. All rights reserved.