On the ”Efficient Pairing-based Threshold Proxy Signature Scheme with Known Signers”

[[abstract]]In 2005, Qian et al. proposed a pairingbased threshold proxy signature scheme with non-repudiation property. However, this paper points out that their scheme is not secure against both the original signer forgery attack and the universal forgery attack. Furthermore, an improved scheme is proposed to avoid the weaknesses on Qian et al.’s scheme