There are at least two reasons why Darkcoin is so interesting to me:
- It is the most popular privacy-centric crypto-currency to date, with the largest market capitalization.
- The privacy technology is based primarily on the CoinJoin protocol first proposed for implementation in Bitcoin. Much of the technology included in Darkcoin’s privacy approach, Darksend+ is adaptable to Bitcoin clients. It is the best funded and most actively developed CoinJoin implementation in the world, currently.
This is the first deliverable from my crowd-funded analysis of Darkcoin’s privacy technology, Darksend+. This paper discusses the design of Darksend+, identifies strengths and weaknesses of the technology, and proposes potential mitigations and improvements to any weaknesses identified.
Since much of the design of Darksend+ can inform other CoinJoin implementations, I hope that this paper will not only shed light on the current state of Darksend+, but provide insight into how to analyze future CoinJoin implementations in general.
I would like to thank Evan Duffield and Justus Ranvier for generously giving their time to review the paper and providing feedback.
Currently I consider the document to be an early version, and request public comment. As mistakes are identified and clarifications are required, I will continue to update the document.
-Kristov