On-Chain Verifiable Credential with Applications in Education

Abstract

A veriable credential (VC) has been standardized and applied in vari- ous domains, including education. Due to its immutability, blockchain has been considered and used for credential issuance and verication. Most existing methods, however, are not compatible with the W3C VC stan- dard. In this paper, an on-chain VC issuance and verication method has been described. The method is based on the standard VC data model and applicable to any credential type. It decomposes a VC document into a VC template and the corresponding value array(s). This allows a VC to be issued on-chain in the Bitcoin BTC network, which has a limited data- embedding capacity. The proposed method reduces blockchain resource consumption due to the reusability of a VC template. In addition, it al- lows the use of a concise VC ngerprint format instead of a full VC for credential exchange. Two issuance modes, namely the full on-chain and partial on-chain, are proposed targeting dierent use cases. The proposed method has been applied for issuing and verifying two learning creden- tial types. The method was evaluated on the Bitcoin Testnet to measure time and space complexities. With the reduced-size VC ngerprint, the proposed method can embed a VC on a traditional paper-based creden- tial as a compact-sized QR code. The proposed method oered faster VC issuance and verication than an existing standard-based veriable creden- tial method.