A Blockchain-Based Access Control Architecture Using Non-Transferable NFTs and Gas-Efficient IPFS URI Management

Abstract

This paper presents a decentralized authorization framework that employs non-transferable Non-Fungible Tokens (NFTs), also known as soul-bound tokens (SBTs), to deliver tamper-resistant, identity-bound access control. Access rights are permanently linked to a user's blockchain wallet and can be upgraded via metadata updates without reminting, enabling dynamic tier management while preventing resale or delegation. The architecture combines an ERC-721 smart contract backend with a decentralized front-end interface for wallet-based authentication and administrator-controlled content distribution. Implementation on the Binance Smart Chain test network demonstrates secure and cost-effective access management with tiered content control. An experimental evaluation quantifies the gas costs associated with NFT minting, tier upgrades, and InterPlanetary File System (IPFS) metadata storage. Results show that using the native Base32 encoding of IPFS content identifiers reduces storage gas costs by approximately 6% compared to the previously standard Bitcoin-style Base58 encoding. Furthermore, shorter uniform resource identifiers (URIs) avoid costly expansions of the storage slots of the Ethereum Virtual Machine (EVM), which can increase transaction costs by 20,000 gas per slot. These findings provide practical guidelines for designing scalable and cost-effective NFT-based authorization systems. Source code and implementation details are available on GitHub.