As we have noted here previously, Ethereum will be releasing a comprehensive but not backward compatible upgrade to the blockchain as implemented for Bitcoin. Similar efforts are happening with Counterparty, who intend to provide an upgrade in place. Concealing transactions are a key feature for both of these efforts.
One team is skipping ahead with an effort focused on anonymous transactions, and they have just announced a cryptography focused white paper entitled ShadowCash: Zero-knowledge Anonymous Distributed E-Cash via Traceable Ring Signatures (pdf).
What Is Shadow Cash?
ShadowCash (SDC) is itself a proof of stake cryptocoin. There are mobile wallets for Android and iPhone, as well as Mac and Windows desktop apps. The coin is traded on several exchanges: CoinSwap , Bittrex , Lazycoins, and Cryptsy. There are a small number of buy orders around the 0.05BTC point on Coin Swap.
The coin has a blockchain explorer and a wiki that offers the following definition:
ShadowCash is a state of the art, Proof of Stake crypto currency, utilizing cutting edge technology, such as instant p2p encrypted messaging (ShadowChat), and anonymous dual-key stealth addresses (ShadowSend). Initial distribution was done using Proof of Work and Proof of Stake.
There are a great many altcoins out there, and almost all are some sort of scam, pump and dump attempts by shady operators who are confused, but excited by all of the fiat and cryptocurrency sloshing around. The slick Shadow.cash site, the supporting explorer and wiki, trading on four major exchanges, wallets for all major platforms, and the features found within the wallet itself all combine to dispel any such concerns about ShadowCash.
An Applied Cryptography Advance?
Evaluating the public face of the community is one thing, but what are we to make of this graph and five pages of heavy duty math?
User and investors are confronted with an impenetrable maze of equations, but the Overview contains what we need to see to be comfortable; a call for peer review of the combination of methods the paper offers:
In this paper we will present our anonymous cryptographic transaction protocol which utilizes: dual-key stealth addresses, traceable ring signatures, and non-interactive zero knowledge proofs.
We prove how our scheme introduces a much higher level of privacy and anonymity to the network while still preserving the core principles of trustless decentralization, unforgeability, and double-spend prevention. We will also present performance data of our scheme that includes proof sizes, signature generation times, and verification times.
Finally, we will present planned future improvements to the current scheme. We present this paper as a first draft towards receiving peer review.
Top Class Reviewers
When asked who their A list reviewers for the anonymous transaction code were, Sebastian from ShadowCash talked to the rest of the team and came back with the following five individuals:
- Matthew Green @matthew_d_green
- Adam Back @adam3us
- Nick Szabo @NickSzabo4
- Ian Miers @secparam
- Trevor Perrin @trevp__
The assessment of new coins and exchanges from an economic perspective benefits from a fairly broad base of expertise. The ability to critically read a new application of cryptographic algorithms with an eye for both innovation and potential errors is a much smaller set of individuals. ShadowCash is, at a bare minimum, a cryptocoin to keep an eye on for the sake of the innovations the team is producing, and forward looking analysts and investors will want to get a wallet and start working out the market details for themselves.
Images from Shadow Cash and Shutterstock.
