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MRL meeting logs 2019-09-16

parent 1ad4ea8c
---
layout: post
title: Logs for the Monero Research Lab Meeting Held on 2019-09-16
summary: Sarang work, and miscellaneous
tags: [dev diaries, community, crypto, research]
author: el00ruobuob / sarang
---
# Logs
**\<sarang>** OK, it's time for the meeting!
**\<sarang>** Agenda: https://github.com/monero-project/meta/issues/390
**\<sarang>** Logs posted there afterward
**\<sarang>** GREETINGS
**\<mikerah>** Hello
**\<sarang>** I'll wait a couple of minutes in case anyone else shows up
**\<kinghat>** o/
**\<kinghat>** \*the regular crowd shuffles in\*
**\<el00ruobuob>** Hi
**\<sarang>** Our pal suraeNoether said he may not be available for today's meeting
**\<sarang>** But I can share some of the things I've been working on for our ROUNDTABLE
**\<sarang>** The ever-clever RandomRun posted an idea for a signature scheme earlier: https://github.com/monero-project/research-lab/issues/56
**\<sarang>** Some updates have been made for efficiency, and I worked up proof-of-concept code: https://github.com/SarangNoether/skunkworks/tree/lrs/lrs
**\<sarang>** And a timing/space analysis: https://github.com/SarangNoether/skunkworks/blob/sublinear/triptych.md
**\<sarang>** (I gave it the name Triptych as a placeholder, so we have a name to use for clarity)
**\<sarang>** It actually beats Lelantus in terms of 2-2 transaction size
**\<sarang>** But verification is less efficient
**\<sarang>** Also note that security hasn't been proven yet, but it uses a modification by Bootle et al. to a 1-of-N proof by Groth
**\<sarang>** and that 1-of-N has good proofs
**\<sarang>** Aside from that, I've been working with the Lelantus authors on some ideas to fix its self-spend tracing problem
**\<sarang>** And that's coming together nicely
**\<sarang>** The CLSAG paper will be submitted to Financial Cryptography this week
**\<sarang>** And my CCS funding request for next quarter has been opened: https://ccs.getmonero.org/proposals/sarang-2019-q4.html
**\<sarang>** On a more whimsical note, a preprint was just posted that does some analysis on a card-based cipher originally designed by Bruce Schneier for a book: https://arxiv.org/abs/1909.06300
**\<sarang>** It's a neat example of a cipher that appears to resist a good deal of modern cryptanalysis, but can be done using paper, pen, and a deck of playing cards!
**\<mikerah>** ElsieFour also has such properties except without the playing cards.
**\<sarang>** Ah, and I'd be remiss if I didn't mention the trustless recursive SNARK paper, Halo, that was recently posted by the Zcash folks
**\<sarang>** mikerah: I wasn't familiar with that!
**\<sarang>** Has it undergone much analysis?
**\<mikerah>** Here's the preprint: https://eprint.iacr.org/2017/339.pdf
**\<sarang>** neat
**\<mikerah>** I'm not sure if it has gone through much analysis as it's a relatively new construction.
**\<mikerah>** But you can use paper and pen!
**\<sarang>** Halo has some clever ideas in it, but it's worth noting (as usual) that preprints don't undergo peer review, and that Halo currently lacks a soundness proof
**\<sarang>** It will be fun to see the new research that comes from its ideas
**\<sarang>** Any particular questions on the items that I mentioned?
**\<mikerah>** How would the ideas from lelantus get implemented in monero?
**\<sarang>** Its transaction model could, hypothetically, be implemented directly
**\<sarang>** Using a particular kind of migration transaction to transition older outputs
**\<sarang>** It would result initially in a smaller anonymity set
**\<sarang>** Currently Lelantus has a tracing issue that's a deal-breaker IMO
**\<sarang>** but very recent ideas mean that may not be a problem
**\<mikerah>** Would there be traceability problems from the current monero blockchain to this hypothetical lelantus+monero blockchain?
**\<sarang>** How so?
**\<mikerah>** As in, would it be possible to trace transactions between hard forked blockchains
**\<sarang>** In such an implementation, old-style transactions would not be allowed
**\<sarang>** Old outputs would undergo a signer-ambiguous transaction to generate a new output commitment that is Lelantus-compatible
**\<doxxy>** sarang: greets
**\<sarang>** So a migration is trivially distinguishable, but retains the same kind of signer ambiguity that exists now
**\<sarang>** hi
**\<sarang>** To be clear, there are no plans to implement this AFAIK
**\<mikerah>** I see. I guess more work would need to be done on this front.
**\<sarang>** It's all just research
**\<sarang>** Anyway, that's what I've been working on
**\<sarang>** Does anyone else wish to share interesting research?
**\<sarang>** OK!
**\<sarang>** Well, in that case my ACTION ITEMS are administrative stuff for FC submission, ongoing analysis of Lelantus modifications and proofs, and returning to some existing recent proving systems
**\<sarang>** Before we adjourn, is there anything else to discuss?
**\<gingeropolous>** i don't have any research im working on, but im enjoying banging my head regarding the randomx branch prediction problem
**\<sarang>** Go on!
**\<gingeropolous>** so, big chunk of CPU silicon dedicated to branch prediction. Turns out a lot of the methods use neural networks kinda thing (called perceptron at one point).
**\<gingeropolous>** however, problem is that randomx is random - its random whether a branch will be taken
**\<gingeropolous>** and when somethings random, hard for machine-learning / pattern recognition to get any gains
**\<sarang>** Makes sense
**\<gingeropolous>** however, if you try and seed random into the program (such that a branch predictor could find some emergent pattern), this information could be harvested by an ASIC or some other mitigation
**\<gingeropolous>** so, my head sorta got stuck at that point... and if it'd be possible to somehow hide the emergent pattern... and then all the thought threads frayed
**\<sarang>** So, using information from existing CPU architectures in order to develop better specialized hardware?
**\<sarang>** Or information from any kind of well-designed predictor, I suppose
**\<gingeropolous>** well the general randomx problem is to make a PoW that leverages stuff in CPUs.
**\<gingeropolous>** and branch prediction is underleveraged due to the problem i just described
**\<sarang>** Ah, ok
**\<sarang>** I don't know enough about CPU branch prediction to fully appreciate this, but it sounds interesting nonetheless
**\<sarang>** Anything else of interest to share before the meeting ends?
**\<sarang>** All righty then
**\<sarang>** Thanks to everyone for being here; we are now adjourned!
**\<sarang>** Logs will be posted shortly
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