Lightweight Selective Disclosure for Verifiable Documents on Blockchain
This work addresses privacy concerns in verifiable document systems on blockchain, but it appears incremental as it builds on known cryptographic techniques.
The paper tackles the problem of privacy protection for document holders by proposing an XML format with cryptographic hashing and salts for selective disclosure, enabling partial digital signatures and efficient verification, and demonstrates advantages over existing Merkle tree-based methods.
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.