Research Of Efficient Anonymous Certificateless Multi-receiver Signcryption Scheme

As a one-to-many communication,multi-receiver signcryption can simultaneously perform the signature and encryption within a logical step.It improves the efficiency and reduces the communication cost compared with the traditional signature-then-encryption.In recent years,it has gradually become a research focus.Most of the existing multi-receiver signcryption schemes are identity based,which has the problem of key escrow and may suffer from the attacks from the malicious third party because PKG possesses the private key of users.The certificateless multi-receiver signcryption,which is the combination of certificateless cryptography and multi-receiver signcryption,is proposed to avoid this problem.The private key is generated by KGC and users together,so KGC cannot acquire the user's complete private key and steal the communication.So,the security of the communication is enhanced.At present,there is little research on the certificateless multi-receiver signcryption scheme.The existing certificateless multi-receiver signcryption schemes are not good for performance and efficiency,the main problem is as follows:(1)The use of bilinear pairing and the more number of the scalar multiplication lead to the high computational cost.(2)The existing certificateless multi-receiver signcrpytion schemes only consider the receiver anonymity without the sender anonymity.As the important participant,the privacy protecting of the sender is very important.(3)The truth and reliability of partial private key cannot be guaranteed.The user cannot verify whether the partial private key coming from the KGC is true or not.So these schemes cannot resist the attacks from malicious KGC.To deal with the above problem,we proposed an efficient and completely anonymous certificateless multi-receiver signcryption scheme.Based on ellipse curve discrete logarithm problem,the proposed scheme does not use bilinear pairing which needs a large amount of computation,and the number of the scalar multiplication is much less than the existing schemes.So it reduces the computational cost and increases the efficiency clearly.By use of the polynomial technology,the information that is calculated by sender and is related to each receiver can be mixed and hidden,making it possible to realize the receiver anonymity.By introducing a random number and mixing the sender's identity with it,a signature parameter can be computed to hide the identities of the senders and protect the sender's privacy,which realizes the sender anonymity.Thus,this scheme realizes the anonymity of all the participants.In addition,the proposed scheme satisfies the decryption fairness,and can be widely applied to the pay-per-view TV,video conference and cloud data storage in group communication,and so on.