Lattice-based Deterministic Proxy Re-encryption And Its Applications

With the advent of the era of big data,more and more network security incidents have occurred,which makes people pay more and more attention to the security of information storage and sharing.Proxy Re-Encryption(PRE)emerged as a special public key cryptography primitive for key conversion between ciphertexts.However,with the rapid development of quantum computing technology,the current mainstream public key cryptography based on number theory has been seriously threatened,and it is imminent to seek more secure and efficient postquantum cryptography to ensure information security.Lattice cryptography is a typical type of post-quantum cryptography,which not only has a simple algebraic structure and high computational efficiency,but also has the advantages of small key size,resistance to quantum attacks and provable security,and has broad application prospects.The current research on lattice-based PRE schemes mainly uses random encryption algorithms to construct cryptographic schemes.However,the above PRE schemes have shortcomings such as long ciphertext and key sizes,and low encryption and decryption efficiency.Therefore,this paper focuses on deterministic encryption algorithms.In the research direction,a lattice-based deterministic threshold proxy re-encryption scheme and a lattice-based deterministic identity-based proxy re-encryption scheme are proposed respectively.The innovative results obtained in this paper are as follows:(1)Aiming at the problem that it is difficult to flexibly realize the sharing and efficient search of encrypted data in large databases,this paper constructs a novel threshold-based deterministic proxy re-encryption scheme under the auxiliary input model.The scheme uses secret sharing technology to achieve threshold control.Moreover,while solving the ciphertext search problem in large databases,it is proved that its security can achieve indistinguishable privacy security under the standard model.(2)Aiming at the dependence on public key certificates in public key cryptography and the efficiency of key management and information sharing in databases,this paper constructs a novel lattice-based deterministic identity-based proxy reencryption scheme.The samplepre technology to obtain the private key not only improves the efficiency of encryption and decryption,but also achieves the security of honest re-encryption attacks.