Verifiable Anonymous Identities and Access Control in Permissioned Blockchains

TL;DR

This paper introduces ChainAchor, a system for permissioned blockchains that enables anonymous yet verifiable identities and access control, ensuring privacy and regulatory compliance.

Contribution

It presents a novel approach to identity and access management in permissioned blockchains with unlinkability and optional identity disclosure features.

Findings

Provides anonymous verifiable identities for blockchain entities

Enables access control via simple public-key look-up

Ensures unlinkability of transactions for privacy

Abstract

In this paper we address the issue of identity and access control within shared permissioned blockchains. We propose the ChainAchor system that provides anonymous but verifiable identities for entities on the blockchain. ChainAchor also provides access control to entities seeking to submit transactions to the blockchain to read/verify transactions on the the permissioned blockchain. Consensus nodes enforce access control to the shared permissioned blockchain by a simple look-up to a (read-only) list of anonymous members' public-keys. ChainAnchor also provides unlinkability of transactions belonging to an entity on the blockchain. This allows for an entity to optionally disclose their identity when a transaction is called into question (e.g. regulatory or compliance requirements), but without affecting the anonymity and unlinkability of their remaining transactions.