Research Of Anonymous Identity-Based Encryption And Its Application

Identity-based encryption system simplifies the key management in traditional public key encryption system.In an Identity-based encryption system,the public key of a user can be computed directly based on the user's own identity information,such as name and email address.The private key of a user is generated directly by the private key generation center.Identity-based encryption system eliminates the public key certificates,which reduces the storage and verification process of public key certificates and greatly saves the resources.Aiming at the fact that most of the current Identity-based encryption schemes do not have the receiver anonymity,this paper proposes a new anonymous identity-based encryption scheme.Based on the DBDH assumption in bilinear group of compo:site order,our scheme achieves selective identity chosen plaintext(ANON-IND-sID-CPA)security under the standard model.On the other hand,the new scheme is anonymous,which means that the adversary cannot get any information about the plaintext or receiver's identity from the ciphertext.Finally,this paper compares the new scheme with several identity-based encryption schemes of the same type,which shows that the new scheme has certain advantages in the anonymity and the encryption and decryption efficiency.Based on the previous scheme,this paper proposes another new anonymous identity-based encryption scheme.Under the premise of preserving the anonymity,this new scheme achieves chosen plaintext(ANON-IND-ID-CPA)security under the standard model.It has higher security than the previous scheme.Therefore,its application scenario is more flexible.Finally,this paper applies the new scheme to the public key encryption system with keyword search,and constructs a public key encryption scheme with keyword search.