Security of Authenticated Encryption Scheme with Message Linkages

Recently, Tseng et al. proposed an authenticated encryption scheme with message linkages to reduce the computation time and communication costs for large message transmissions. However, in 2005, Zhang et al. pointed out that Tseng et al.´s scheme does not achieve non-repudiation property because the scheme is based on Horster et al.´s scheme. Furthermore, they proposed a new authenticated encryption scheme with message linkages based on the meta-message recovery signature scheme to overcome the weakness in Tseng et al.´s scheme. However, the current paper demonstrates that Zhang et al´s authenticated encryption scheme with message linkages still does not achieve non-repudiation property for messages in which an attacker can forge the valid signature blocks and pass the receiver´s verification