PITCOR: Privacy-assured Time-controlled Revocation in Blockchain Transactions

The proliferation of blockchain technology is based on decentralization, transparency, and security. The inherent openness and transparency of blockchain are beneficial for trust and accountability but pose a significant challenge to privacy. Besides, outdated access to the blockchain data also leads to privacy leakage. This needs time-controlled access revocation for the blockchain transactions. In this paper, we introduce a privacy-preserving framework, Privacy-ensured Time-COntrolled Revocation (PITCOR), leveraging advanced techniques including Public key Encryption-based Keyword search (PEKS), InterPlanetary File System (IPFS), and Private Information Retrieval (PIR). PITCOR also uses time-controlled revocation to update the access rights of the blockchain data. We implement PITCOR on Ethereum and HyperLedger Fabric (HLF). PICTOR shows a throughput of 56 Transaction Per Second (TPS) and 50 TPS with latency of 8.5 ms and 7.7 ms for Ethereum and HLF, respectively. Demonstrating efficacy against privacy attacks, PITCOR provides robust protection, making it a promising solution for addressing privacy concerns in blockchain applications.