Meeting summary: Monero Research Lab, 4 October 2023

This is a comprehensive summary, with added reference links, of the MRL meeting¹ from October 4th 2023, 1700 UTC.

Logs

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

231004-mrl.log (86 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: 5 (Rucknium², tevador³, j​effro256⁴, rbrunner⁵, UkoeHB⁶)

• (1) Updates

  • (1.1) on JAMTIS, wallet2’s decoy selection algorithm⁷:

    • j​effro256 has been working with Rucknium, discussing and implementing Jamtis changes, trying to formalize wallet2 decoy selection algorithm

  • (1.2) on statistical research:

    • Rucknium was also working on excluding the set of txs with nonstandard fees from analysis of on-chain ring member age⁸

• (2) Open discussions

  • (2.1) on JAMTIS design changes:

    • tevador asked if there was enough consensus to go forward with the Jamtis changes

    • j​effro256 was looking to dive deeper into one issue⁹ that he recently mentioned on the JAMITS gist: multiple self-send enotes within a transaction creates a significant statistical fingerprint for finding outgoing enotes for anyone with knowledge of the find-received/assist-filter/filter-involved key

    • tevador generally agreed with the change regarding self-send enotes, but noted that it has a potential to increase the required wallet traffic 2.5x or more

    • jeffro256 thought that most people are already in agreement about using the extra public key to guard against third-parties knowing the nominal address tags

    • tevador brought up previous pushback against dynamic view tags and reiterated his opinion that the proposed Jamtis changes might not be worth it without them¹⁰

    • rbrunner mentioned that a Reddit poll for support of variable size viewtags only had around 40 voters in total and felt like things were still pretty much in flux, not yet ‘converging’ to a solution

    • Rucknium was interested in finding other potential use cases for pre-signed transactions, signed days+ in advance besides atomic swaps and shared a link to the LightSwap: An Atomic Swap Does Not Require Timeouts At Both Blockchains paper¹¹; j​effro256 replied, mentioning dead man switch scenarios and transaction ceremonies that can take a while to complete but don’t necessarily make fingerprintable decoy selections

    • j​effro256 thought that light wallets will take a bigger part in the ecosystem from Jamtis onwards, especially with mobile wallets

    • tevador noted that although possible to hardfork in the future to adjust the view tag, Monero would be stuck with the address format forever

    • tevador confirmed to rbrunner that deciding how many keys to have is much more important than choosing between fixed size and flexible viewtags

    • j​effro256 thought that the pros of the extra public key in the address far outweigh the downsides and proposed flexible sized view tags by hard consensus rules, but which the relay rules enforce a constant size

    • tevador noted that the 3rd key would help everyone with the Janus attack protection and a separate key to view amounts, while the 4th key would only benefit light wallet users

    • UkoeHB was wondering if consensus was reached for the proposed JAMTIS changes; j​effro256 replied that he is in agreement with tevador on most issues: a key derivation tree, public address layout, and sender-receiver secret derivation scheme if we choose to add the extra pubkey to the address, and underlined the main point of contention: how to do the view tags

    • tevador thought that a soft-rule for view tags would probably work, but considered the 3-key/4-key debate unsettled regardless of the view tag decision; j​effro256 added that a soft-rule flexible view tag would allow switching to dynamic view tags without a consensus change; tevador agreed

    • tevador was wondering if there is any data on the number of 3rd party scanners users, which could make the 4th key most likely worth it

    • rbrunner thought that light-wallet use under Jamtis has the potential to become a stampede and mentioned third-world countries where you still buy your mobile data traffic in megabytes

    • Rucknium quoted and linked fluffypony’s comment on MyMonero users/txs - Whilst we don’t disclose user numbers, I can assure you that the number of viewkeys we have is not even double-digit percentages¹², before concluding that discussions about dynamic view tag length and the 4th public key will continue in future meetings

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

Feedback, edits always welcome @/about.

-3RA