Content Extraction Signatures(CES)improve the efficiency of multiparty interaction and resolve the problem of multiple signature and communication. Documents' format becomes messy after messages extraction in the traditional CES scheme. To solve this problem, based on RSA, combining the batch signature idea, this paper promotes a new CES scheme and analyses the effects of the extractor's behaviors to the verification of signature. Compared with the traditional CES, the new scheme optimizes the structure of ...