A Forgery Converted Signature Attack on the Novel Authenticated Encryption Scheme with Convertibility

In 2013, Thadvai et al. proposed a novel authenticated encryption scheme with convertibility. They claimed that the proposed scheme satisfies all the properties of an ideal authenticated encryption scheme (AES). However, this paper shows that Thadvai et al.’s AES scheme still suffers from a forgery converted signature attack, that is, any one Corresponding author: Ki-Dong Bu ([email protected]) 2798 Hae-Jung Kim, Eun-Jun Yoon and Ki-Dong Bu can forge a valid converted signature of a signer on an arbitrary message. Certainly, the secure requirement against the forgery converted signature attack should also be concerned about. Mathematics Subject Classification: 94A60, 11T71, 14G50, 68P25, 81P94