Abstract

Decentralized peer-to-peer (P2P) systems and blockchain technologies each address centralization and tampering risks; combined, they can enable auditable, censorship-resistant data sharing for sensitive applications. Conventional P2P sharing either depends on centralized access-control or leaks metadata and authority to intermediaries, exposing users to privacy, integrity, and single-point-of-failure risks. Achieving fine-grained, verifiable access control while preserving confidentiality and scalability remains a challenge. We propose TrustlessShare, a hybrid architecture that anchors compact metadata on a permissioned blockchain while keeping encrypted payloads off chain in a distributed hash table (DHT). Smart contracts implement capability tokens (timebound, revocable), a lightweight reputation ledger, and on-chain anchors for content hashes and policy digests. End-to-end encryption uses ephemeral content keys distributed via asymmetric capability exchange. Privacy is strengthened by metadata minimization, selective disclosure proofs, and optional mix routing for request blinding. A small consensus layer handles policy operations while peer discovery and content transfer remain fully P2P. Prototype evaluation shows that blockchain anchoring adds minimal latency to authorization (sub-second in common scenarios), enforces revocation reliably, and enables complete audits of access history without exposing content. The approach tolerates node churn, reduces centralized attack vectors, and scales storage costs via off-chain content addressing. TrustlessShare thus offers a practical, privacy-aware path to secure, trustless data sharing.

Authors

Sathish Krishna Anumula¹, S. Vimala²
IBM Corporation, Hyderabad, India¹, Prathyusha Engineering College, India²

Keywords

Blockchain, Peer-To-Peer, Trustless, Encrypted DHT, Smart Contracts