Certificateless multi-receiver signcryption method with multivariate-based cryptosystem

The invention discloses a certificateless multi-receiver signcryption method with a multivariate-based cryptosystem. The certificateless multi-receiver signcryption method is used for solving the technical problem of poor security of an existing certificateless signcryption method. The technical scheme includes that the method includes: firstly, using a key generation center to generate system parameters, and selecting a secure multivariable encryption algorithm to generate keys; and enabling a user U to obtain system private keys of the key generation center and generate the private keys to user keys prior to that a user Alice with the identity IDA sends signcryption messages to a user group L={ID1, ID2,...,IDt}, and accepting or refusing ciphertext sigma by means of un-signcryption. By the aid of the multivariate-based cryptosystem, high security of anti-quantum computation is achieved, and the certificateless multi-receiver signcryption method is still high in security facing attack of a quantum computer.