Abstract:

Integrating the selfcertified public key technique and signcryption system enables both digital signature and encryption simultaneously in a fitted logical procedure and eliminates the certificate management problem and the key escrow problem. It has lower computational cost and saves the storage space, so it is important for us to construct secure and efficient self certified signcryption schemes. Analysis of Yu’s and Wang’s papers shows that they are not secure.The third can forge signature instead of the true signer with a pair of clear text and cipher text. We improve their schemes by rooting a random number in the digital signature scheme.Our improvement overcomes their disadvantage and achieves a higher security.
      

Key words: self-certified public key;selfcertified signcryption;discrete logarithm problem;attack