Identity-Based Proxy Re-Encryption (IB-PRE) allows a semi-trusted proxy to convert the ciphertext encrypted under Alice’s identity into Bob’s ciphertext of the same message without leaking plaintext. Lattice-based c...Identity-Based Proxy Re-Encryption (IB-PRE) allows a semi-trusted proxy to convert the ciphertext encrypted under Alice’s identity into Bob’s ciphertext of the same message without leaking plaintext. Lattice-based cryptography enjoys potential resistance to quantum analysis and low computational complexity. A multi-hop and unidirectional IB-PRE from lattices is presented. We split the functions of decryption and ciphertext transformation separately, and design the double private keys mechanism, where two keys are generated for each user, one key is used to decrypt the ciphertext by Pre-Image Sampling technique, and the other is used to generate the re-encryption key by Bonsai Trees technique. The generation of the re-encryption key is non-interactive and collusion resistant. Moreover, its IND-sID-CPA security over the decisional Learning With Errors (LWE) assumption under the standard model is proved. Compared with some previous IBPRE schemes from Bilinear Pairings, the format of transformed ciphertext in our scheme remains unchanged, furthermore, it can also resist quantum analysis. Compared with some existing IB-PRE schemes from lattices with similar properties, the space of the message in our scheme is a vector of length l and the encryption process remains a lower encryption blowup factor. At last, a proof-of-concept implementation is provided.展开更多
Data security is vital for medical cyber physical system (MCPS). The decentralization feature of blockchain is helpful to solve the problem that the secure authentication process is highly dependent on the trusted thi...Data security is vital for medical cyber physical system (MCPS). The decentralization feature of blockchain is helpful to solve the problem that the secure authentication process is highly dependent on the trusted third party and implement data security transmission. In this paper, the blockchain technology is used to describe the security requirements in authentication process. A network model of MCPS based on blockchain is proposed. Through analysis of medical data storage architecture, data was ensured not to be tampered and trackable. The security threat was eliminated by bilinear mapping in the authentication process of medical data providers and users. The credibility problem of the trusted third party was avoided and the two-way authentication was realized between the hospital and blockchain node. The security analysis and performance test were carried out to verify the security and related performance of the authentication protocol. The results show that the MCPS based on blockchain realizes medical treatment data sharing, and meets safety requirements in the security authentication phase.展开更多
基金supported by the National Natural Science Foundation of China under grant No.(U1636114, 61572521,61772550)Natural Science of Shaanxi Province of China under grant No.2018JM6078Innovative Research Team in Engineering University of PAP (KYTD201805)
文摘Identity-Based Proxy Re-Encryption (IB-PRE) allows a semi-trusted proxy to convert the ciphertext encrypted under Alice’s identity into Bob’s ciphertext of the same message without leaking plaintext. Lattice-based cryptography enjoys potential resistance to quantum analysis and low computational complexity. A multi-hop and unidirectional IB-PRE from lattices is presented. We split the functions of decryption and ciphertext transformation separately, and design the double private keys mechanism, where two keys are generated for each user, one key is used to decrypt the ciphertext by Pre-Image Sampling technique, and the other is used to generate the re-encryption key by Bonsai Trees technique. The generation of the re-encryption key is non-interactive and collusion resistant. Moreover, its IND-sID-CPA security over the decisional Learning With Errors (LWE) assumption under the standard model is proved. Compared with some previous IBPRE schemes from Bilinear Pairings, the format of transformed ciphertext in our scheme remains unchanged, furthermore, it can also resist quantum analysis. Compared with some existing IB-PRE schemes from lattices with similar properties, the space of the message in our scheme is a vector of length l and the encryption process remains a lower encryption blowup factor. At last, a proof-of-concept implementation is provided.
文摘Data security is vital for medical cyber physical system (MCPS). The decentralization feature of blockchain is helpful to solve the problem that the secure authentication process is highly dependent on the trusted third party and implement data security transmission. In this paper, the blockchain technology is used to describe the security requirements in authentication process. A network model of MCPS based on blockchain is proposed. Through analysis of medical data storage architecture, data was ensured not to be tampered and trackable. The security threat was eliminated by bilinear mapping in the authentication process of medical data providers and users. The credibility problem of the trusted third party was avoided and the two-way authentication was realized between the hospital and blockchain node. The security analysis and performance test were carried out to verify the security and related performance of the authentication protocol. The results show that the MCPS based on blockchain realizes medical treatment data sharing, and meets safety requirements in the security authentication phase.
