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.
@article{arxiv.1807.10554,
title = {Coloured Ring Confidential Transactions},
author = {Felix Engelmann and Frank Kargl and Christoph Bösch},
journal= {arXiv preprint arXiv:1807.10554},
year = {2018}
}