Blockchain-based privacy-preserving SaaS acquisition through NFTs and Ricardian contracts
Abstract
Current Software-as-a-Service (SaaS) platforms require users to disclose personal information during service registration, which implies privacy risks and regulatory compliance challenges, particularly in privacy-sensitive domains such as healthcare, financial analytics, research computing, and decentralized knowledge platforms. This paper presents a proof-of-concept blockchain-based framework enabling anonymous service acquisition through non-fungible tokens (NFTs) linked to legally-interpretable Ricardian contracts. The system combines smart contracts for token management, InterPlanetary File System (IPFS) for decentralized contract storage, and pseudonymous wallet addresses to decouple user identity from service acquisition. Users acquire services by obtaining NFTs that serve as both digital receipts and proofs, with each token cryptographically linked to a personalized Ricardian contract stored on IPFS. The framework addresses a significant gap in privacy-preserving service acquisition for domains where anonymity is both feasible and essential, providing a scalable alternative to traditional identity-based registration systems without compromising contractual transparency or verifiability. Performance evaluation shows Ricardian contracts upload times of 350-750ms and retrieval times under 35ms across different contract sizes. Economic analysis demonstrates feasibility with individual service acquisition costs of approximately \$3.50, while batch processing reduces costs up to 86\% through deployment cost amortization. Privacy analysis confirms that no personally identifiable information is stored on-chain, with contractual relationships recorded only through pseudonymous wallet addresses, achieving compliance with data minimization principles while enabling legal enforceability.