Coloured Ring Confidential Transactions

TL;DR

This paper introduces a novel privacy-preserving transaction type for blockchains that allows confidential trading of multiple asset types using coloured ring signatures, enabling asset tracking without compromising privacy.

Contribution

It extends ring confidential transactions with colour commitments and verifiable proofs, allowing multiple asset types to be traded privately on a common blockchain.

Findings

Supports multiple asset types with same anonymity set size

Enables asset tracking without revealing transaction details

Maintains privacy while ensuring asset conservation

Abstract

Privacy in block-chains is considered second to functionality, but a vital requirement for many new applications, e.g., in the industrial environment. We propose a novel transaction type, which enables privacy preserving trading of independent assets on a common block-chain. This is achieved by extending the ring confidential transaction with an additional commitment to a colour and a publicly verifiable proof of conservation. With our coloured confidential ring signatures, new token types can be introduced and transferred by any participant using the same sized anonymity set as single-token privacy aware block-chains. Thereby, our system facilitates tracking assets on an immutable ledger without compromising the confidentiality of transactions.