Abstract:

Signcryption scheme is an integration of signcrypted signature and encryption system,which is different from the traditional firstsignatureandthenencryption system,and which achieves both confidential and certified services for the transferred information within a logical step.Thus how to design a safe and efficient signcryption scheme is particularly important. We analyze the security flaws in the existing literature which do not meet unforgeable requirement,that is,there is a known forgery attack against the plaintext and ciphertext.Any third party can steal plaintext and ciphertext,and counterfeit signcrypter legitimate signatures for any messages,which seriously harms the interests of signcrypters.

Key words: elliptic curve;self-certified signcryption;discrete logarithm problem;proxy re-encryption