Security notes on generalization of threshold signature and authenticated encryption
In 2000, Wang et al. proposed a (t, n) threshold signature scheme with (k, l) threshold shared verification, and a (t, n) threshold authenticated encryption scheme with (k, l) threshold shared verification. Later, Tseng et al. mounted some attacks against Wang et al.'s schemes. At the same, they also presented the improvements. In this paper, we first point out that Tseng et al.'s attacks are actually invalid due to their misunderstanding of Wang et al.'s Schemes. Then, we show that both Wang et al.'s schemes and Tseng et al.'s improvements are indeed insecure by demonstrating several effective attacks.
security threshold signature authenticated encryption digital signature cryptography