The invention discloses a certificateless-based
signcryption method and a certificateless-based
signcryption system, belonging to the field of
signcryption technologies. The certificateless-based signcryption method and the certificateless-based signcryption
system comprise a third-party KGC (
Key Generation Center partial private
key generation center) and a user module, wherein the third-party module comprises an online task
distributor, a partial private
key generator and an Hash arithmetic unit which are connected through a
secure channel; the user module comprises a user secret value generator, a user full private
key generator, an offline signcryption
machine, an online signcryption
machine and a
decipher, and the signcryption operation is carried out on a user through the steps of generating
system parameters, generating a user secret value, generating a user partial private key, generating a user full private key, carrying out offline signcryption, carrying out online signcryption and decoding in sequence. According to the certificateless-based signcryption method and the certificateless-based signcryption system, signcryption effectively replaces a simple method of combining
encryption and a signature through a logic unit, so that the online / offline signcryption can be implemented under the certificateless environment safely and effectively, and determination of identity of a
receiver is not needed in an offline stage, and the certificateless-based signcryption method and the certificateless-based signcryption system have the advantages of high efficiency, good safety, large flexibility and strong applicability.