What Is RuffCT and How Will It Affect Monero?

Achieving anonymity with cryptocurrency is not straightforward at all. It often requires either the involvement of third-party service providers or some advanced technology and cryptography. In the case of Monero, anonymity is mainly provided thanks to the use of Ring Confidential Transactions, or RingCT. It appears the developers are looking for ways to further improve upon this technology. A new proposal by Tim Ruffing dubbed “RuffCT” aims to achieve this goal. Now is a good time to look into what all of these changes could mean for Monero.

Taking RingCT to the Next Level

In a research paper written by Tim Ruffing, Viktoria Ronge, Dominique Schroder, and Sri Aravinda Krishnan, the concept of improved Ring Confidential Transactions was proposed. As most Monero users are well aware, RingCT effectively allows users to hide their XMR transaction amounts. This technology has been implemented for quite some time now and powers nearly 95% of all Monero transactions today. This goes to show the technology is greatly appreciated by Monero supporters who want additional anonymity when using cryptocurrency.

There are other benefits to RingCT-based transactions as well. This technology allows users to hide not just the transaction amount, but also the origin and destination of any transfer. All of that is achieved with “reasonable efficiency” and is done in a trustless manner. There is no need to rely on a third-party service provider to remove taint from coins and successfully obfuscate the origin and destination address. This has been hailed as one of the major advancements introduced by Monero‘s developers. However, there is always room for future improvement, which is exactly what this white paper aims to achieve.

The new technology is currently dubbed “RuffCT” by the Monero developers, even though Tim Ruffing is only one of the four authors of the white paper. The proposal involves using Confidential Transactions combined with sublinear ring signatures.  Implementing this technology would expand ring signature sizes to over 100,000, although it remains to be seen if such a high number is actually feasible. For now, it seems the current ring size in Monero will be greatly expanded although not necessarily to such a scale as originally assumed.

Although this technology sounds quite exciting, Ruffing advises Monero users to remain level-headed for the time being. For now, signatures are more compact for larger ring sizes. However, the computation time required to verify these “RuffCT” signatures are similar to how larger RingCT verification occurs right now. There is no notable speed advantage to using one over the other, which does not make RuffCT stand out from the current implementation. This is something the team is still working on and it may take a while to figure out how to optimize everything. Reasonable ring sizes right now are somewhere below 1,000 at best.

While still in the early stages of implementation, RuffCT offers significant improvement in transaction size. As most cryptocurrency users are well aware, there is a limited amount of blockchain space for any cryptocurrency. Without a block size increase, there is only so much “space” to contend for. RuffCT will provide a way for Monero to scale to larger rings without requiring larger network blocks or anything of that sort. A lot of work still needs to be done in this regard and peer review by developers is expected to take place as well.

It appears the main limiting factor for the current implementation of RuffCT is CPU power. That is not necessarily a big issue on paper, but it may introduce some other changes to the Monero fee structure if it cannot be resolved. It will be interesting to see if this proposal is implemented a few months from now. For the time being, the community patiently awaits the release of the white paper, expected “soon.”