Lightweight selective disclosure for verifiable documents on blockchain

• Main Authors: Kenji Saito, Satoki Watanabe
• Format: Article
• Language: English
• Published: Elsevier 2021-09-01
• Series: ICT Express
• Subjects: Selective disclosure; Content extraction signature; Privacy; Proof of existence; Blockchain
• Online Access: http://www.sciencedirect.com/science/article/pii/S2405959521001016

To achieve lightweight selective disclosure for protecting privacy of document holders, we propose an XML format for documents that can hide arbitrary elements using a cryptographic hash function and salts, which allows to be partially digitally signed and efficiently verified, as well as a JSON format that can be converted to such XML. The documents can be efficiently proven to exist by representing multiple such structures as a Merkle tree and storing its root in blockchain.We show that our proposal has advantages over known methods that represent the document itself as a Merkle tree and partially hide it.