A Collusion-Resistant Blockchain-Enabled Data Sharing Scheme with Decryption Outsourcing under Time Restriction

• Published in: Security and communication networks 2021, Vol.2021, p.1-11
• Main Authors: Shen, Xieyang, Huang, Chuanhe, Shen, Xiajiong, Shi, Jiaoli, Wang, Danxin
• Format: Article
• Language: English
• Subjects: Access control; Algorithms; Blockchain; Cloud computing; COVID-19; Cryptography; Data retrieval; Encryption; Information sharing; Outsourcing; Performance evaluation; Personal health; Security; Security management; Servers
• ISSN: 1939-0114; 1939-0122
• DOI: 10.1155/2021/7249470

With the ever-increasing demands on decentralization and transparency of cloud storage, CP-ABE (Ciphertext Policy-Attribute-Based Encryption) has become a promising technology for blockchain-enabled data sharing methods due to its flexibility. However, real-world blockchain applications usually have some special requirements like time restrictions or power limitations. Thus, decryption outsourcing is widely used in data sharing scenarios and also causes concerns about data security. In this paper, we proposed a secure access control scheme based on CP-ABE, which could share contents during a particular time slot in blockchain-enabled data sharing systems. Specifically, we bind the time period with both ciphertexts and the keys to archive the goal of only users who have the required attributes in a particular time slot can decrypt the content. Besides, we use time slots as a token to protect the data and access control scheme when users want to outsource the decryption phase. The security analysis shows that our scheme can provide collusion resistance ability under a time restriction, and performance evaluations indicate that our scheme uses less time in decryption compared to other schemes while ensuring security.