Meeting summary: Monero Research Lab, 5 April 2023

This is a comprehensive summary, with added reference links, of the MRL meeting¹ from April 5th 2023, 1700 UTC.

Logs

The raw, unedited, full log file for this meeting:

230405-mrl.log (158 lines)

Summary

Note: it is possible that some relevant information may be missing from this summary; read the full log file for the complete, unedited discussion.

• Participants: 17 (UkoeHB², ArticMine³, compdec⁴, rbrunner⁵, Rucknium⁶, tevador⁷, hbs⁸, jeffro256⁹, vtnerd__¹⁰, narodnik¹¹, blankpage¹², ofrnxmr¹³, Alex-LocalMonero¹⁴, Lyza¹⁵, plowsof11¹⁶, sech1¹⁷, politicalweasel¹⁸)

• (1) Updates

  • (1.1) on decoy selection improvements & the Monero Light Wallet Server¹⁹:

    • jeffro256 implemented the solution for MRL issue #109 (Avoid selecting coinbase outputs as decoys²⁰) in PR #8815²¹

    • Rucknium started reviewing jeffro256’s code to avoid selecting coinbase outputs when spending non-coinbase outputs

    • vtnerd was working on LWS stuff and also reviewed jberman’s Decoy selection algo off-by-1 patch²²

  • (1.2) on Seraphis/JAMTIS:

    • UkoeHB referenced his new CCS²³, updated the Seraphis paper²⁴ (minor cleanup, cut out implementation recommendations, simplified composition proof writeup, added grootle proof construction + security proof), and was preparing to write the jamtis-instantiation companion paper next

  • (1.3) on Mordinals²⁵:

    • Rucknium noted, after monitoring the ‘Mordinals’²⁶ project, that in the last 3 days Mordinal minting has essentially ceased and announced plans to do a write-up next week on the empirical privacy effects of Mordinals (+ coinbase outputs)

  • (1.4) on elliptic curves²⁷:

    • narodnik started writing the benchmarks: now im doing the normal pedersen commit, have the scheme written in sage, then will begin constructing circuits with modified ECIP proof to benchmark against normal pedersen commit

• (2) Open discussions

  • (2.1) on tx_extra²⁸:

    • UkoeHB reiterated his position²⁹ against removing the tx_extra field; blankpage agreed 99% with UkoeHB’s comment

    • Rucknium thought that UkoeHB’s encrypted by default statement was a little misleading to most readers if the encryption rule would have no enforcement mechanism whatsoever; UkoeHB clarified that there would not be wallet2, since the change is planned for Seraphis, and the core library would encrypt/decrypt tx extra contents by default

    • jeffro256 mostly agreed with UkoeHB’s stance, but argued in favor of making the field mandatory, assuming there is consensus to keep tx_extra: giving transaction constructors the option of having it be present is a bigger privacy issue than initially assumed

    • tevador agreed that the field should be made mandatory if the portion of transactions using tx_extra will be significant

    • UkoeHB shared what the conservative development path would look like: unconstrained -> optional -> mandatory (-> removed); ofrnxmr didn’t see a use for the in-between optional step

    • rbrunner pointed at the clear lack of consensus about the main question (‘remove’ versus ‘keep in some form’): We are stuck there

    • plowsof11 dropped in to announce that the relevant Monero version 0.18.2.2 was tagged³⁰

    • ofrnxmr was interested in tevador’s thoughts about standardizing outputs; rbrunner thought the addition of this adjacent topic to the already difficult tx_extra debate would not make things easier

    • Alex-LocalMonero thought that keeping tx_extra was signaling that arbitrary data injection has a stable standardized place on the Monero blockchain, which would be counter-productive towards Monero’s goals, concluding that arbitrary data storage on the XMR chain should be disincentivized to the greatest practical extent; however, if arbitrary data was to be stored on the chain it should look just like any other tx data

    • sech1 replied to Alex’s position, noting that arbitrary data can be stored in outputs, ~30 bytes per output and it’s impossible to stop it and a fixed small tx_extra is better than forcing arbitrary data into outputs; Alex commented that Nobody is forcing anyone to use outputs, people can use CLSAG too

    • UkoeHB announced plans to implement tx_extra pruning + optional encrypted field in the seraphis library as a temporary solution and noted that he would be open to future incremental changes

    • Alex-LocalMonero called for making arbitrary data unstable, inefficient, costly, and ideally indistinguishable from other data; sech1 was not prepared to change his opinion until a way to prevent stuffing arbitrary data into outputs is discovered; UkoeHB thought that protocol instability was the opposite of what the project should aim for; Alex disagreed in the context of arbitrary data injectors

    • rbrunner proposed abbreviating arbitrary data injectors to ADIs; Alex liked the idea

    • ofrnxmr proposed adding the standardizing in/out discussion to agenda of future MRL meetings

Let me know if you find this kind of report helpful.

Feedback, edits always welcome @/about.

-3RA