Research On Certificateless Aggregate Signcryption And Anonymous Hierarchical Broadcast Encrytion

As computer networks are integrated into all aspects of life,complex network environments require a variety of encryption algorithms.Since the public key cryptography algorithm has been proposed,a variety of algorithms have been derived,especially in order to resist quantum computer attacks,an encryption algorithm based on lattice theory has been produced,but the cost is relatively high.In fact,in order to pursue cost performance,it is not simply to increase the strength of the algorithm,but to choose the encryption algorithm that suits the needs.This article studies the signcryption and encryption schemes in two practical scenarios,and the main work is as follows:(1)In the many-to-one scenario,aiming the previous aggregation signcryption scheme,which requires multiple bilinear operations and exponential operations,and the calculation efficiency is low,this thesis proposes a safe and efficient based on the certificateless model Aggregate signcryption scheme without bilinear pairing.The proposed scheme aggregates the previous certificateless signcryption and optimizes the encryption process.The parameters used in the aggregate decryption are added to the hash function of the generated key.The security is guaranteed and the computational complexity is reduced without the bilinear pairing.After analyzing the security and efficiency of the random prediction model,the proposed scheme avoids the linearization of the key,under the Hash function with strong collision resistance,it has confidentiality and unforgeability,and has higher calculation efficiency.(2)In the broadcast scenario,in order to solve the problem of low efficiency of the key distribution mechanism in the previous anonymous broadcast encryption,this thesis proposes a hierarchical anonymous broadcast encryption scheme.Based on the existing anonymous broadcast encryption scheme,the users in the broadcast are layered into a tree structure,and the private key of the parent layer user and the public parameters are used to generate the private key of the sub-layer user,which reduces the PKG's burden.The proposed scheme extends the security model of anonymous broadcast encryption to anonymous hierarchical broadcast encryption.Theoretical analysis shows that the proposed scheme is completely anonymous and supports the encryption of messages from any set of arbitrary receivers,and only selected users and their parent users can decrypt.And it owns unforgeability and indistinguishability.