monero-site/_posts/2019-07-29-logs-for-the-Monero-Research-Lab-meeting-held-on-2019-07-29.md
el00ruobuob ca61c34564
Meeting logs update:
+ dev diaries tag added to all backlog
+ MRL 7/29, 8/5, 8/20, 8/26, 9/2
+ Dev 8/11, 8/25
+ Community 8/3, 8/17, 8/31
+ tini2p 8/8, 8/22, 9/5
2019-09-06 17:41:08 +02:00

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---
layout: post
title: Logs for the Monero Research Lab Meeting Held on 2019-07-29
summary: Sarang work, Surae work, and miscellaneous
tags: [dev diaries, community, crypto, research]
author: el00ruobuob / sarang
---
# Logs
**\<sarang>** OK, let's begin
**\<sarang>** Hello all
**\<sarang>** Logs of this meeting will be posted to the GitHub agenda issue afterward
**\<sarang>** GREETINGS
**\<suraeNoether>** greetings!
**\<kenshamir[m]>** hey
**\<sarang>** Whoops, here is the current agenda: https://github.com/monero-project/meta/issues/377
**\<sarang>** Let's go ahead with ROUNDTABLE
**\<sarang>** I've been working hard on an RCT3 implementation, integrating some nice optimizations and seeing if it's possible to get key images working as expected
**\<sarang>** This also led to a bunch of other library updates that the code relies on
**\<sarang>** So generally just a lot of coding
**\<sarang>** I also gave a fun lecture on the Enigma cipher machine and the math behind it, which is always fun ;)
**\<suraeNoether>** nice, what was that for? a meetup or something?
**\<sarang>** A friend teaches at a university and thought it would be good for an undergrad crypto class
**\<sarang>** Since the Enigma break is all about permutation groups
**\<suraeNoether>** nice
**\<sarang>** I should be able to finish up an integration of the BP inner product verifier optimization into RCT3 shortly
**\<sarang>** Then, of course, DEF CON approaches!
**\<suraeNoether>** neat
**\<suraeNoether>** i have a very dirty branch on my computer with my matching simulations and experiments being worked upon
**\<sarang>** How are those going?
**\<hyc>** defcon - anyone got grasshopper repellent?
**\<sarang>** -\_\_\_\_-
**\<suraeNoether>** i've proven all the theorems necessary to prove that the algorithm in graphtheory.py does what i claim it does, and i'm currently testing that my simulated ledgers are doing what i expect.
**\<sarang>** noice
**\<sarang>** Will be very neat to see the results, and to see if/how they can work with the analysis that Isthmus et al. are doing on Monero and Zcash
**\<suraeNoether>** in addition to that, i have a bunch of MAGIC stuff I need to get done, and my discussions with isthmus' digital forensics work are leaning in that direction
**\<suraeNoether>** i'm thinking the content of this project may take up more than two papers :\\
**\<sarang>** Cool!
**\<sarang>** Also worth noting that the CLSAG paper has been updated on IACR, thanks mainly to kenshamir[m]'s comments and questions
**\<sarang>** kenshamir[m] has also been working on a Rust implementation of CLSAG/MLSAG using the dalek library
**\<suraeNoether>** hyc: i hear grasshoppers are delicious, i wonder if any of those fancy vegas michelin star restaurants are capitalizing on the swarm
**\<sarang>** Anything you'd like to share on that, kenshamir[m] ?
**\<kenshamir[m]>** Hi, the library is finished, not interopable with monero because it uses a different curve though. The numbers are quite impressive and I believe it is due to the way cLSAG was created
**\<sarang>** aw shucks
**\<sarang>** Will be great to see your MLSAG vs CLSAG numbers at different ring sizes
**\<suraeNoether>** i believe there was a question re: ristretto and multi-exp like pippenger right before the meeting that would be relevant here?
**\<sarang>** I brought it up a while back because we handle different linear combination sizes \_very\_ differently in the codebase
**\<scoobybejesus>** is that rust code in a public repo?
**\<sarang>** We use no fewer than 4 methods
**\<kenshamir[m]>** The numbers above were for different ring sizes, I may have mis-typed key sizes by accident
**\<kenshamir[m]>** 256 and 512 were for the decoy sizes; if I was not clear
**\<sarang>** A big part of the reason CLSAG verification is faster than MLSAG is because of the introduction of a new linear combination evaluation algorithm
**\<sarang>** kenshamir[m]: can you link them again for the logs?
**\<sarang>** (if comfortable having them public)
**\<kenshamir[m]>** \<scoobybejesus "is that rust code in a public re"> Not the cLSAG code, once I add documentation and sanitise it I can post it in here
**\<sarang>** ty
**\<kenshamir[m]>** \<sarang "kenshamir: can you link them aga"> Yep sure
**\<scoobybejesus>** :)
**\<sarang>** What does "without Pippenger/Straus" mean? Simple iterative evaluation of linear combinations?
**\<kenshamir[m]>** Yep exactly
**\<sarang>** Impressive numbers
**\<sarang>** Of course, it's a different hash function
**\<kenshamir[m]>** I just did scalarbase mult in a for loop
**\<kenshamir[m]>** haha yeah that too
**\<suraeNoether>** hmmmmm
**\<sarang>** But if the hash function is the same across both of your CLSAG/MLSAG, then the relative numbers are good
**\<suraeNoether>** something that is both faster and smaller and with equivalent security is a no-brainer for implementation (pending audits)
**\<sarang>** Speaking of this, still in contact with potential auditors, who are moving very slowly
**\<sarang>** Nothing to report on that front :/
**\<suraeNoether>** the improved space allows for a logarithmic increase in verification time without actually slowing down the network (at least when it comes to new nodes downloading the network). judging by these numbers, a ring size of 16 or 32 is no longer like pouring molasses or concrete onto the network
**\<sarang>** OK, any other interesting research to report?
**\<gingeropolous>** re: audits, or roll-out in general. Is this the kind of thing that could be rolled-out in parallel with existing? i.e., have an overlap, where the network uses the existing as the primary / default, but can optionally use the new thing, and then once new thuing is vetted, just prune the old?
**\<hyc>** ^ slow auditors - a lot of people are on summer holiday now
**\<gingeropolous>** or, switch to the new and no longer have to relay / verify the old style during the overlap?
**\<suraeNoether>** sarang: am i wrong in saying that gingeropolous is correct that clsag could be implemented in parallel before mlsag is deprecated?
**\<hyc>** we had a 24hr overlap in the last hardfork for this sort of thing
**\<gingeropolous>** this would be kinda different.
**\<sarang>** I suppose it could be overlapping, provided the fee model supports it properly
**\<sarang>** I don't really see why this would be useful
**\<gingeropolous>** i dunno. i'm just opening the conversation regarding the model that all new things need to be audited
**\<gingeropolous>** i mean, obvi auditing is great
**\<sarang>** yes
**\<gingeropolous>** but its not perfect
**\<dEBRUYNE>** hyc: Yeah in general, summer constitutes low activity
**\<sarang>** It's good for inspiring confidence, as well as the obvious benefits of catching any errors
**\<kenshamir[m]>** Can Monero benefit from using bulletproofs for arithmetic circuits?
**\<dEBRUYNE>** gingeropolous: Didn't we discuss that kind of model for Bulletproofs or RingCT too?
**\<sarang>** Likely not, with our current tx model
**\<gingeropolous>** yeah dEBRUYNE
**\<sarang>** The scaling isn't great
**\<dEBRUYNE>** I think it was shot down for good reasons, but I cannot remember them exactly :-P
**\<gingeropolous>** i think that was post audit though
**\<sarang>** and we have hash functions, which screw things up
**\<sarang>** Zooko had a slide in some presentation where his team estimated the verification time for a circuit with the complexity of Sapling (Sprout? don't recall)
**\<sarang>** and BP verification was O(1 s)
**\<sarang>** Compared to our current verification time which is probably 1/50th of that
**\<sarang>** maybe 1/100th
**\<kenshamir[m]>** yikes
**\<suraeNoether>** kenshamir: if we designed an arithmetic circuit to describe a ring confidential transaction language, then yes, but that's sort of what RCT3 and omniring and lelantus try to do... sarang, i think zooko was showing "what it would look like for a Sapling transaction language to be proven in the bulletproof setting" not ring confidential transactions, so it's not clear to me whether it'd be slower.
**\<suraeNoether>** in our setting
**\<suraeNoether>** with the exception of our non-AC-compatible hash function
**\<dEBRUYNE>** sarang: That's verification time for fully shielded transactions?
**\<suraeNoether>** dEBRUYNE yeah, iirc
**\<dEBRUYNE>** Yikes
**\<sarang>** Yeah, that timing was just to give an example of what a production-size tx circuit might look like
**\<dEBRUYNE>** Especially given that, as far as I know, you have to run a full node in order to properly perform fully shielded transactions
**\<dEBRUYNE>** Anyway, I digress :-P
**\<sarang>** Anyway, suraeNoether is right in that RCT3 and Omniring try to bring the BP benefits to specific languages used to prove RingCT-type statements
**\<sarang>** which is why we're interested in them
**\<suraeNoether>** yeah, bulletproofs for use in SNARK-style languages is like... uhm... putting a large-diameter turbofan engine into a Mini Cooper. It's not going to do what you think it's going to do.
**\<sarang>** BPs can be much more efficient for languages built for it
**\<sarang>** which is why range proofs are so efficient
**\<kenshamir[m]>** haha
**\<suraeNoether>** indeed
**\<suraeNoether>** moving along
**\<sarang>** heh
**\<sarang>** ok, other research?
**\<sarang>** Or QUESTIONS, from the agenda?
**\<sarang>** OK then! To ACTION ITEMS
**\<sarang>** I'll be finalizing some things for my DEF CON talk, workshop, and panel; and finalizing some RCT3 integration optimizations
**\<sarang>** suraeNoether: ?
**\<suraeNoether>** oh gosh sorry
**\<suraeNoether>** i was computing a number sorry about that. :P
**\<sarang>** it's 7
**\<suraeNoether>** my action items are: work on sims and the experimenter, and work with isthmus to formalize statistical hypotheses for testing all this
**\<sarang>** Having data from Isthmus's group will be extremely valuable for this kind of analysis
**\<suraeNoether>** actually the number is O(153.58\*N), which is the number of bits used to describe the number of possible spend histories at ring size 32 with N outputs.
**\<suraeNoether>** which is nutters
**\<sarang>** This is all assuming no external information?
**\<sarang>** Or other graph-based information on chain reactions and provably-spent outputs?
**\<suraeNoether>** merely the total number of self-consistent spend histories
**\<sarang>** Ah ok, so for a hypothetical graph
**\<suraeNoether>** yeah
**\<sarang>** got it
**\<gingeropolous>** O(153.58\*N) ... great. now your math is talking in math
**\<suraeNoether>** well it means that for, say, 1000 transactions at ring size 32, there are 2^(153,580) possible spend histories.
**\<suraeNoether>** anyway
**\<suraeNoether>** (N has to be a lot bigger than the ring size for the above formula to hold btw)
**\<sarang>** which is... quite reasonable
**\<sarang>** Any other final thoughts or questions before we adjourn?
**\<sarang>** OK then! Thanks to everyone for participating. We are adjourned