Certifichain: Secure QR Codes for Blockchain-Verified Digital Credentials

A blockchain-based digital credential securely verifies identity and prevents fraud through decentralized validation. In recent applications, QR codes link these credentials, facilitating quick verification. Earlier research showed QR codes lacked subject data, making them easy targets for forgery and quishing attack. This study developed Certifichain, an application designed to manage digital credentials within a blockchain, integrating secure QR code tagging to provide a dual credential verification mechanism. The secure QR code holds both the encrypted digital credential object and the digital signature as the subject. The encryption scheme utilizes the Advanced Encryption Standard (AES) and the Elliptic Curve Digital Signature Algorithm (ECDSA). Powered by Hyperledger Fabric, the system supports up to 200 transactions per second with high throughput and low latency. The system achieves a usability score of 89 while maintaining an average CVSS score of below 2.1 from the STRIDE threat model, indicating both high usability and minimal risk. The system surpasses other QR code schemes in recent blockchain applications by providing confidentiality, integrity, authenticity, and non-repudiation from subject verification.