From 1c8b1ace7cf0401b9f7444bb92dbb5997e39d98a Mon Sep 17 00:00:00 2001 From: el00ruobuob <bruno.labour@gmail.com> Date: Mon, 11 Mar 2019 19:34:19 +0100 Subject: [PATCH] MRL meeting logs from 2019-03-11 + correction after test --- ...Research-Lab-meeting-held-on-2019-03-11.md | 198 ++++++++++++++++++ 1 file changed, 198 insertions(+) create mode 100644 _posts/2019-03-11-logs-for-the-Monero-Research-Lab-meeting-held-on-2019-03-11.md diff --git a/_posts/2019-03-11-logs-for-the-Monero-Research-Lab-meeting-held-on-2019-03-11.md b/_posts/2019-03-11-logs-for-the-Monero-Research-Lab-meeting-held-on-2019-03-11.md new file mode 100644 index 00000000..8c619d0e --- /dev/null +++ b/_posts/2019-03-11-logs-for-the-Monero-Research-Lab-meeting-held-on-2019-03-11.md @@ -0,0 +1,198 @@ +--- +layout: post +title: Logs for the Monero Research Lab Meeting Held on 2019-03-11 +summary: Network upgrade, Point release discussions, MRL work, and miscellaneous +tags: [community, crypto, research] +author: el00ruobuob / sarang +--- + +# Logs + +**\<sarang>** Our meeting begins presently +**\<sarang>** Let's go ahead and get started. Agenda is here: https://github.com/monero-project/meta/issues/314 +**\<suraeNoether>** howdy everyone +**\<sarang>** 1. GREETINGS +**\<sarang>** hi +**\<MRL-discord> \<Isthmus>** Hello! Biking, in soon. +**\<parasew[m]>** hello! +**\<sarang>** Let's recap 2. NETWORK UPGRADE +**\<sarang>** Kudos to everyone for a successful first upgrade +**\<sarang>** I don't recall when the second was slated to occur, since block arrival was stunted +**\<sarang>** Any thoughts on the upgrade after the fact? +**\<xmrmatterbridge> \<rehrar>** Hi +**\<sarang>** I believe it was dEBRUYNE who wanted an upcoming meeting specifically to talk more deeply about the future of PoW +**\<parasew[m]>** anyone monitored the "old chain"? if there have been this large amount of asics on there, and not turned off it should be visible +**\<sarang>** I believe sgp\_ ran some blackball numbers on it +**\<sarang>** and found essentially nothing of interest +**\<sarang>** but as far as hashrate, I am not sure +**\<sgp\_>** yeah, no chain reactions so far, very few known spent outputs through reused key images +**\<sgp\_>** impact on network privacy so far is essentially 0 +**\<sarang>** sgp\_: were the key image reuse numbers for only v9 and v10? +**\<sgp\_>** yes, just those two +**\<sarang>** great, thanks +**\<sarang>** Relating to this, we can also introduce 3. NEXT POINT RELEASE +**\<sarang>** Not all desired non-consensus changes made it in to this release, so Sometime Soon (tm) will be a point release +**\<sarang>** BP optimizations will be one nice addition +**\<sarang>** I would like output selection to also be included... we talked about it at length at an earlier meeting +**\<dEBRUYNE>** sarang: Correct. It's a topic with a lot of depth that requires an extensive discussion imo +**\<sarang>** suraeNoether: do you have a current recommendation for output selection? +**\<suraeNoether>** i'm running into problems testing the matching code, based on this problem too +**\<sarang>** Here is a discussion of the different algorithms: https://github.com/monero-project/meta/issues/307#issuecomment-466514757 +**\<suraeNoether>** iirc the output lineup method performs quite well +**\<sarang>** I prefer it among the others that were tested +**\<sarang>** But it's a change that deserves more than two thumbs-up :) +**\<suraeNoether>** there is no optimal solution, but some solutions are better than others and the output lineup method is more reasonable than the other proposals, and i have no new proposals to make (yet) +**\<sarang>** I updated the sim code (link in agenda) to examine the output weighting in more details +**\<sarang>** Hopefully the BP optimizations are less contenious +**\<suraeNoether>** uhm i think i have one possible proposal that i want to chat about with you by side channel to hash out some details +**\<sarang>** sure +**\<sarang>** We should have a formal recommendation before whatever date is set for the point release code freeze +**\<sarang>** Anything else relating to the point upgrade that ought to be discussed? +**\<sarang>** ping moneromooo perhaps +**\<xmrmatterbridge> \<rehrar>** I just want timelines. Nothing to say on content. +**\<moneromooo>** hi +**\<moneromooo>** What's the question ? :) +**\<moneromooo>** I don't know about any date. Depends when we get all the stuff on master ready really. +**\<sarang>** Anything relating to the next point release you'd like us to discuss? +**\<moneromooo>** None that come to mind right now. +**\<sarang>** ty +**\<sarang>** In that case, let's move to 4. ROUNDTABLE +**\<sarang>** suraeNoether: care to go first? +**\<sarang>** OK, I can go first instead +**\<suraeNoether>** ok +**\<sarang>** aha, go ehead +**\<suraeNoether>** heh +**\<suraeNoether>** Well, my simulations for the matching code are to the point where i'm running a matching on some test data now to generate a confusion matrix. +**\<suraeNoether>** i'm also editing the manuscript describing the whole process +**\<suraeNoether>** one of the problems i'm running into is actually simulating our output selection in part because it's not clear which direction we are going yet +**\<suraeNoether>** and it occurred to me that this could help inform our choice of output selection by seeing if one of these possibilities makes matching easier or harder +**\<sarang>** IMO matching expect spend with proper weighting seems optimal enough from a purely timing perspective +**\<sarang>** (leaving out questions of binning etc) +**\<suraeNoether>** when i say easy or hard i don't mean in terms of time, because as we've seen matching is essentially super duper fast +**\<suraeNoether>** i mean in terms of false negative and false positive rates +**\<suraeNoether>** but you are 100% on that +**\<sarang>** aw shucks +**\<suraeNoether>** i'm working on a variety of other side things but i'm shooting for this matching paper to be complete and published some time in the next 2 months +**\<sarang>** Excellent +**\<suraeNoether>** if we get more speakers for the konferenco, then i won't be speaking, but otherwise i will probably be presenting on this at the konferenco +**\<sarang>** Neat; anything else of interest to share? +**\<suraeNoether>** that's all i have today, thanks! +**\<sarang>** Righto +**\<sarang>** I have a few things +**\<xmrmatterbridge> \<learninandlurkin>** The line up is looking great btw! Fantastic effort for a first konferenco +**\<suraeNoether>** catching up on lots of reaidng in algebraic geometry :D +**\<sarang>** First, my next FFS/CCS will be posted soon +**\<sarang>** As was discussed here, in -community, and elsewhere, the request will be for immediate payout +**\<sarang>** This means both donors and I know the actual value of the donations +**\<sarang>** Since this is a big change, any questions or comments on it? +**\<sarang>** (presumably suraeNoether will be doing the same arrangement) +**\<suraeNoether>** i'm in support of this, and i will indeed be mimicking this +**\<sarang>** Folks who do not trust us to run with the money should, of course, not donate +**\<sarang>** But my hope is that our records have shown we're good for it :D +**\<binaryFate>** happy we came to that solution eventually, hopefully will be better for your guys +**\<sarang>** Thanks to binaryFate and others for agreeing to this change +**\<binaryFate>** yes the idea is that donors being careful should discourage randomers to do the same +**\<sarang>** The CCS posting will \_very\_ clearly state the arrangement, so there is no confusion +**\<binaryFate>** If you figure out the markdown +**\<sarang>** Yes indeed +**\<moneromooo>** Technically, it's within the existing rules as stated: one milestone, which consists of "sarang starts working" :) +**\<sarang>** Second, the paper that suraeNoether and I have been collaborating with external researchers on (DLSAG et al.) is in final review now +**\<sarang>** We've been asked not to share it before it's released as a preprint, as a courtesy to all authors +**\<suraeNoether>** \*nod\* +**\<sarang>** It has some great details on useful constructions that I'm sure we'll discuss at length after the preprint goes to IACR +**\<sarang>** it'll be submitted for a conference as well +**\<sarang>** Third, I wrote up some additional tests and code for Bulletproofs MPC +**\<dEBRUYNE>** sarang: How does this work if the proposal is not fully funded yet when your period starts? +**\<sarang>** Two options: either the bulk is paid out and it stays open until filled +**\<sarang>** or it all sits there until fully funded +**\<sarang>** I prefer the first, but am open to discussion +**\<sarang>** Regarding Bulletproofs MPC, real\_or\_random had some great thoughts on this before the meeting (but I won't put him on the spot) +**\<suraeNoether>** i imagine that the important part is laying out which way it goes in the proposal +**\<sarang>** the question has to do with what a malicious player can do +**\<sarang>** We chatted about the fact that an evil player could try to pull what amounts to a cancellation of partial proof elements, effectively setting the inputs to the hash that generates a F-S challenge +**\<sarang>** I couldn't find a way that this could be used as an exploit, aside from obviously generated an invalid proof +**\<sarang>** but the security proofs for BPs do require that F-S challenges are uniform +**\<sarang>** I had neglected that point when I had thought about this earlier +**\<sarang>** My strong suspicion is that proof elements are still uniformly distributed in the presence of a dishonest challenge due to the prover's randomness, and that you still get zk in this case (but not provably) +**\<sarang>** Moral: if we do anything in the future that requires/desires this scheme, these things would need to be considered +**\<sarang>** Any questions/comments relating to this? +**\<sarang>** allrightythen +**\<suraeNoether>** i think we should continue to ponder it and write something up formally about the BP MPC schemes +**\<sarang>** Well that's the thing... there's really nothing to write formally +**\<sarang>** You can probably solve all the theoretical woes by having all players commit to their proof elements before multicasting them +**\<sarang>** then an honest prover is guaranteed uniform F-S challenges +**\<xmrmatterbridge> \<learninandlurkin>** Sorry but I'm a little out of the loop here. What exactly are BP MPC for? something to do with multisig with BP? +**\<suraeNoether>** it's nice to think about collectively computing BP range proofs, but I'm still v curious about the coinjoin approach that we are considering on the larger scale. +**\<sarang>** Ideally, untrusted parties could generate single BPs for outputs +**\<suraeNoether>** after all, it's hard to even think about threat models unless we know how these things will be used in practice +**\<sarang>** Sure, this is all pie-in-the-sky right now +**\<suraeNoether>** learninandlurkin: collaborating with friends to compute a range proof for a coinjoin style transaction, so that the participants don't reveal their amounts to each other +**\<sarang>** But yes, the threat model would be very different depending on how the rounds go +**\<sarang>** Finally, suraeNoether had shown me this a while back: https://lelantus.io/lelantus.pdf +**\<suraeNoether>** agreed on the commit-and-reveal; expensive but usually does the trick to ensure participants can't be rewound inappropriately +**\<sarang>** An interesting application of some of the fundamentals behind Bulletproofs and the old StringCT scheme +**\<xmrmatterbridge> \<learninandlurkin>** So... allowing multi-input transactions where each user doesn't know the amounts of the other inputs? Sounds useful +**\<suraeNoether>** learninandlurkin hence our interest in nailing down threat models \*nod\* +**\<sarang>** I've been playing around with some of the math in that paper to see what nuggets could be extracted +**\<suraeNoether>** oh i had a brief thing to point out: isthmus and n3ptune at noncesense-research-lab answered one of my requests and we now have a complete empirical distribution of number of inputs and outputs per transaction +**\<suraeNoether>** forgot to mention this: +**\<sarang>** Neato, where is this distribution to be found? +**\<suraeNoether>** https://github.com/noncesense-research-lab/tx\_in\_out\_distribution +**\<suraeNoether>** the data surprised me +**\<dEBRUYNE> \<sarang>** I prefer the first, but am open to discussion <= I'd be OK with the first, but perhaps it would be most convenient to use a rounded number +**\<dEBRUYNE>** e.g. if 211 XMR is funded, pay out 200 +**\<sarang>** You won't believe what's in tx\_distribution\_in.csv! +**\<dEBRUYNE>** Mebbe malware +**\<dEBRUYNE>** :P +**\<suraeNoether>** super heavy tails for one thing, and a rootkit for another +**\<sarang>** dEBRUYNE: perhaps a full payout at date X, and then a second payout at either date Y or completion, whichever comes first +**\<binaryFate> \<sarang>** I prefer the first, but am open to discussion <-- donors will have no incentive to fund in time, it will drag till the end of the period +**\<sarang>** binaryFate: how would you do it? +**\<binaryFate>** I like the incentive to donors of you proposing something and getting to work on it only if funded +**\<xmrmatterbridge> \<learninandlurkin>** I imagine coinjoining going on would really complicate output selection. Or is there some idea where they work off each other to get rid of heuristics? +**\<sarang>** Depends on how timely it is +**\<suraeNoether>** learningandlurkin coinjoin brings a whole new nightmare to the party. does everyone bring their own mix-ins? certainly nothing is to stop a malicious party from coinjoining with a bunch of badly selected mix-ins +**\<moneromooo>** A ring is one person only. Fake output selection is untouched. +**\<sarang>** Well each input signs with its own ring +**\<sarang>** ^ +**\<moneromooo>** That person makes their own ring, yes. Otherwise others would know which is the real out. +**\<sarang>** The benefit is breaking the assumption of one-party control of outputs and the link to the input rings +**\<binaryFate>** What about simple attack of using the same 10 decoys as one of the other participants? +**\<suraeNoether>** ^ +**\<msvb-mob>** Is parasew, nevvton, or txmr in the channel? +**\<binaryFate>** mmm you don't know which are decoys, nevermind ^^ +**\<sarang>** If this moves forward, hopefully we can determine the necessary practical security for BPs +**\<sarang>** If we can't aggregate, they'd have to be separate for each output +**\<suraeNoether>** my beard is getting very thoroughly stroked this morning. much to think about... +**\<sarang>** I believe we'd get practical security without player commitments, but not provable +**\<sarang>** Anyway: does anyone else wish to share interesting research before we close? +**\<xmrmatterbridge> \<learninandlurkin>** Yes it sounds like the interplay between coinjoin and ringsigs will require some diagrams for me to ever understand. Could get complicated. +**\<suraeNoether>** i think you would want a commit-and-reveal stage for everyone to see the ring members to prevent malicious ring intersection in the coinjoin +**\<sarang>** MoneroCoinJoin: an easy 14-round process! +**\<suraeNoether>** isthmus and i have been chatting about methods of extracting the true spend-time distribution from the monero blockchain without knowing exactly which outputs have been spent +**\<suraeNoether>** that's a very nascent conversation, though I think it'll end up being a very straightforward project +**\<sarang>** Discussions in #noncesense-research-lab I presume? +**\<xmrmatterbridge> \<learninandlurkin>** so, truish spend-time distribution +**\<binaryFate>** Are there regular meetings on this or just continuous discussion? I had been working on this at some point and have some code around aiming to graphically show the real spend distribution +**\<sarang>** I've seen a few informal conversations in #noncesense-research-lab but didn't know if suraeNoether had something more formal +**\<suraeNoether>** binaryFate: ah, no, this has been a casual conversation by side channel, but there is clearly interest +**\<suraeNoether>** i'll start blabbing about it in here more publicly +**\<sarang>** In the interest of time, let's review 6. ACTION ITEMS and then close to continue discussion afterword +**\<binaryFate>** Ok don't hesitate to ping me on this +**\<sarang>** I will be posting my CCS request soon, tidying up the output selection stuff for a recommendation, getting the DLSAG application paper reviewed and out the door, and playing around with that Lelantus paper when/if I get a chance +**\<sarang>** suraeNoether: ? +**\<suraeNoether>** CCS request, working on simulations and measurable numbers for matching, and looking into using our matching code to answer questions about output selection +**\<sarang>** excellent +**\<suraeNoether>** also casual github maintenance +**\<sarang>** Any final questions or remarks before we adjourn? +**\<xmrmatterbridge> \<learninandlurkin>** once you guys have made a recommendation for output selection +**\<xmrmatterbridge> \<learninandlurkin>** and it gets implemented, what's the next big focus? +**\<sarang>** There will be much to consider in the realm of refund and payment channels +**\<xmrmatterbridge> \<learninandlurkin>** Ooh yes the refund ideas from a while back were really interesting +**\<sarang>** and some aspects of output selection, like linking spends across rings in txns, is not solved yet +**\<xmrmatterbridge> \<learninandlurkin>** Seems like a logical next area of research +**\<sarang>** and if coinjoin works out, there will be a lot to consider with that +**\<sarang>** Also transaction relay and network-level anonymity stuff that's still in progress +**\<sarang>** To quote the Simpsons: "like the cleaning of a house... IT NEVER ENDS" +**\<sarang>** But on that note, our meeting does end +**\<sarang>** Thanks to everyone for attending. We're adjourned; let the conversations continue