Blockchain-Based Digital Rights Management Scheme via Multiauthority Ciphertext-Policy Attribute-Based Encryption and Proxy Re-Encryption

In order to ensure the confidentiality of digital contents, improve the fairness of digital copyright transactions, and reduce the time and management overhead of digital copyright owners, we proposed a blockchain-based digital rights management scheme. First, we designed a new multiauthority ciphertext-policy attribute-based encryption (MA-CPABE) scheme and showed that the new MA-CPABE has the indistinguishability of plaintext under adaptively chosen plaintext attack (IND-CPA) security and good performance. By combining the MA-CPABE and proxy re-encryption, the rights owner can flexibly sell the copyright to different users with once encryption by an agent who cannot access any information related to digital content when changing the ciphertext access policy as required. By using the smart contract of Ethereum, a fair trade of the decryption keys between the rights owner and rights requester is implemented. In order to further improve fairness, another blockchain is used as a ledge to store information related to digital rights, which greatly reduces the storage overhead in public blockchain. Security analysis shows that our scheme can provide IND-CPA security, resist collusion attacks, and protect the user's privacy. Performance analysis shows that our scheme can provide a wealth of features to meet the various needs of users. The simulation results show that our scheme is very efficient compared to other schemes.