November 12, 2018
<suraeNoether> howdy everyone!
<rehrar> …..to quote sarang
<suraeNoether> so, let's flip the usual order of the meeting to allow for questions at the beginning
<suraeNoether> i like that
<suraeNoether> in fact, i'm going to call THAT the new "usual order"
<suraeNoether> so, the agenda today is 1) questions, 2) sarang's research this week and last, 3) mine, and 4) any other project discussion that's remotely relevant to research
<suraeNoether> so, someone give me and sarang your top two questions :D
<nioc> any updates on Konferemco preparations?
<rehrar> I should have a logo and branding guidelines today
<rehrar> in regards to MRL, where are we in the churn and privacy formalizations?
<rehrar> although I assume this will be talked about with your report of the week suraeNoether
<suraeNoether> that is precisely the case
<suraeNoether> i'm in the midst of getting hard numbers for a timing for a practical attack
<suraeNoether> sarang and i have discovered an anonymity metric that could give us a guideline for "how rapidly we need to chagne our ring size with respect to blockchain size to maintain our current levels of anonymity."
<suraeNoether> this is a very useful metric, but it's dangerous to misinterpret it
<sarang> Let us shift that to the later agendum
<suraeNoether> so we're avoiding making formal proclamations about it, but we are going to use it as a rough guideline for future ring size increases
<suraeNoether> nioc our conference organizer has been checking out a few alternative venues, and we have already identified some vendors for things like catering
<sarang> I have a question… how the hell do I build the dalek bulletproof rust implementation for timing testing??!?!?!?!
<sarang> I know jack shiz about rust
<suraeNoether> that's an excellent question that occurred to me yesterday afternoon!
<sarang> they claim to be bonkers fast, even compared to libsecp256k1 (which seems nutso to me)
<suraeNoether> they are claiming some mad speed gainz on top of your already mad speed gainz
<sarang> They don't have batch verification yet tho
<sarang> (it's on their issue list)
<sarang> So I want to run timing tests myself to see
<suraeNoether> if that's the case, then… man that implementation is bonker fast like what-what
<sarang> I don't think they're lying, but I'm also naturally skeptical
<sarang> I don't find it terribly relevant since we're already pretty fast
<suraeNoether> i suspect that bulletproofs are going to benefit from 40 years of optimizations in linear algebra and ECC very very quickly
<sarang> and any changes specific to underlying curve architecture aren't useful for us ATM
<rehrar> sarang: what if it's so fast it can reverse the blackchain continuum?
<rehrar> somethign to look into
<sarang> Ah yes, the chain shrinks over time
<suraeNoether> the blackchain continuum hypothesis, by tom clancy
<suraeNoether> or dan brown
<sarang> Anyway, it won't build for me, but I'll verify timings once I get it figured out
<rehrar> <sarang> Ah yes, the chain shrinks over time <– it will give extra space to your computer when it goes negative
<sarang> However, they also have ideas for non-power-of-2 stuff, which was on the back burner for me
<sarang> if it proves useful for them in a way that translates to us, great
<suraeNoether> nioc i believe we already have enough funding availalbe to put a deposit down on a location, and I would like to do that before the end of 2018. email invitations to speakers will be start being setn out this week
<sarang> Also our other conference FFS (Stanford) was funded recently, so many thanks on that front
<suraeNoether> in general: thank you to all contributors who make Monero Research Lab a funded thing
<sarang> suraeNoether and I will learn next month if either of us will be speaking there
<sarang> anyway, other questions for us?
<sarang> In the absence of further questions, we can talk recent research
<sarang> This past week, I did two events in Chicago
<sarang> one was a hands-on Monero development workshop
<sarang> the other was a more general talk on privacy tech
<sarang> both videos are on YouTube, linked from the Monero Moon posting
<sarang> thanks to the Chicago Bitcoin and Open Blockchains group for hosting me
<suraeNoether> Did you have a good time? think you'll do something like that again?
<sarang> Yeah, I think it was very valuable
<sarang> They had good turnout and excellent questions
<sarang> I really like the workshop idea especially
<sarang> Aside from that work, I did a good amount of lit review to support suraeNoether's work (discussed shortly) on graph matchings, which was an extension of some earlier analysis we did on spent output analysis
<suraeNoether> what was the demographic of the crowd like?
<sarang> The workshop was smaller (due to scheduling shenanigans for some participants) but had folks interested in math/CS/development
<sarang> The talk had a good mix of technical folks and well-wishers
<sarang> It'd be cool to find a way to host an interactive online workshop
<OpenSorceress> what would that entail?
<sarang> Well, one set of tasks I had them do was use a simple Python ed25519 library to build some constructions
<sarang> like Pedersen commitments and Schnorr sigs
<rehrar> lol, love the name OpenSorceress. That's funny.
<sarang> So being able to do video w/ slides for introductory work would be good
<sarang> as well as interactive stuff to help the participants write code
<sarang> Then we did some basic RPC stuff
<OpenSorceress> like remote pairing?
<sarang> OpenSorceress: some situation where the workshoppers could do in-browser code, perhaps, and then let me assist interactively if needed
<sarang> I don't know if there is such a thing already
<sarang> just spitballing here
<suraeNoether> that is pretty awesome, sarang! i'm glad it's online.
<OpenSorceress> there is
<OpenSorceress> -> floobits pops to mind
<sarang> Cool, let's discuss after meeting
<OpenSorceress> :) ok
<sarang> I've also been working to integrate stealth addresses into the RTRSRingStringRuffCT optimizations
<sarang> and other minor tasks, etc
<sarang> How about you suraeNoether? The graph matching, perhaps
<suraeNoether> well, i've been doing the churn and graph theoretic stuff
<suraeNoether> as I mentioned earlier, sarang and I have stumbled upon a class of anonymity metrics for graphs such as ours, and this will give us a quantitative basis for maintaining at least our current levels of anonymity as the blockchain gets larger
<sarang> It's worth noting that this isn't even new analysis
<sarang> But a really clever interpretation of older stuff that suraeNoether came up with
<sarang> which is always great in math
<suraeNoether> correct, in fact several of these were proposed right around the time Bitcoin was proposed, which amuses me
<suraeNoether> 2007, 2008, 2009
<rehrar> so are you saying that as the blockchain gets larger, anonymity decreases?
<suraeNoether> well, consider the following situation
<suraeNoether> let's say something ridiculous like "tomororw Monero goes back to ring size 1"
<sarang> It's important to note that "anonymity" here means "anonymity according to a very specific metric formulation that may or may not correspond to a particular threat model"
<suraeNoether> what happens? a bunch of blocks are added to the monero blockchain, all of which are totally linkable
<suraeNoether> this is an edge case of the following idea:
<notmike> Even I could link them!
<suraeNoether> if we take our present system and add a bunch of non-anonymous stuff, we aren't improving our anonymity
<suraeNoether> in fact, we are decreasing our anonymity, by essentially diluting our nice big fat blockchain filled with fat ring sigs with non-anonymous data
<sarang> At their heart, these metrics use numbers of matchings to relate to some idea of anonymity
<sarang> a graph matching is a possible global spend history, of which there will be many
<sarang> Think of it as being a guess about true spends that's at least _consistent_, but of course not provable
<sarang> My current view of this type of analysis is that, being only a heuristic that could be combined with things like output age, it provides the same types of plausible deniability that ring sigs have always offered
<sarang> what suraeNoether was saying about it being useful to examine proposed changes is a good idea
<sarang> So you can say "if we increase ring size to X given usage patterns Y, this metric implies that anonymity gets better"
<sarang> it's not possible to say things like "anonymity gets Z% better" though
<suraeNoether> so, to answer your question rehrar: the Edman anonymity level is *negatively* related to overall graph size and *positively* related to ring size. so we can say "okay, if our blockchain was *this* big, how big of a ring size would we need to have similar EAL to today?"
<suraeNoether> the fact of the matter is, though, it very slowly changes with respect to graph size at these levels
<rehrar> got it
<suraeNoether> to maintain an EAL similar ot what we have today, the blockchain could be 10x larger
<suraeNoether> and we might need a ring size of like 15 at that point, or something like that, to make it equal exactly
<sarang> I have the same types of broad, non-mathematical questions about global anonymity that I do about rings in general
<sarang> If there are 2^64 possible spend histories, is that good enough for our threat models? What if there were only 2^4? I don't know
<suraeNoether> sarang actually we can sort of answer that question quantitatively
<sarang> Well, for some threat models, "good enough" means "enough reasonable doubt to avoid someone getting in trouble for a spend history they weren't actually involved in"
<sarang> and that depends on how your legal system works
<sarang> What types were you considering?
<suraeNoether> the question an attacker needs to answer is "out of all possible spend histories with a likelihood greater than some C of being the true spend history, what % of these is a specific edge traced?" for example, if in 95% of all plausible and likely histories, edge e sending monero from address X to address Y is included in the matching, we conclude that edge e is the true spender.
<suraeNoether> we may be able to quantify our security on an individual level that way, and see how it is sensitive to game parameters
<suraeNoether> anyway, 100% of my MRL attention is on this paper right now
<sarang> A lot of this (not just graph metrics) seems to be chasing after specific heuristics (some unknown) without a real fundamental idea of what guarantees we want to be able to offer
<sarang> Subtly moving from "not provable spending" to "not heuristically-guessable spending" seems like a generally good idea, but it's like swiss cheese
<suraeNoether> all of my work so far is highlighting, essentially, the urgency with which we need to replace ring signatures
<suraeNoether> and the fundamental problem with using KYC exchanges
<sarang> Well, those aren't going anywhere
<sarang> and if anything, more people will move to them
<hyc> as opposed to DEXs?
<sarang> Do you know of any usable ones?
<hyc> I assume Bisq works
<gingeropolous> bisq .. ?
<hyc> haven't used it
<rehrar> question on replacing ring signatures…is there any sort of tech (eevn un battle tested) that exists at the moment?
<sarang> nor have I
<sarang> rehrar: no
<suraeNoether> i hear bisq is good, but i haven't used it yet
<suraeNoether> rehrar: yes and no
<sarang> not without sacrificing trust
<suraeNoether> or speed/efficiency
<suraeNoether> there are some trustless set-ups that are unreasonably slow
<hyc> if we could do cross-chain atomic swaps with BTC that would eliminate a huge chunk of exchange usecases
<suraeNoether> or big
<sarang> IMO the goal of the graph matching analysis should be to at least get an order-of-magnitude estimate on Monero global spend histories
<suraeNoether> hyc that is 100% correct, and we have all the theoretical framework for that except SPV at this point, but the recent nipopow paper and another recent paper may fix that too
<sarang> I'm not convinced this provides an adversary with remarkably more actionable data than existing heuristics
<OpenSorceress> how would you go about sussing that out?
<sarang> And while it should push us toward better non-ring-sig solutions, I also don't want to FUD our users in the same way that all the other Monero tracking papers have
<suraeNoether> it should provide literally the same amount of data, just one is a global approach and one is a txn-by-txn approach
<sarang> OpenSorceress: run the analysis on at least a portion of the chain
<sarang> suraeNoether: implementing nipopow is a huge undertaking
<sarang> suraeNoether: what do you see as the goal of the analysis?
<suraeNoether> provide actionable advice for the monero community on how to mitigate the worst known traceability chainalsysis attack. ultimately
<sarang> in terms of ring size specifically?
<sarang> given that the EAL is sensitive to it?
<suraeNoether> not necessarily, although that is presently a facet of the analysis, yeah.
<suraeNoether> i mean, at this point, I think that further increases in ring size without order-of-magnitude increases… i'm not convinced of their efficacy, but i can't say either way at this point
<sarang> What's the takeaway from all of this, for the folks in this meeting?
<suraeNoether> research is ongoing into the matter
<suraeNoether> progress is being made in terms of making actionable recommendations to the community
<suraeNoether> but we aren't announcing them yet, until after more consideration
<suraeNoether> i'm not sure what you mean
<rehrar> good enough for me
<sarang> Do you view this a fundamentally new form of analysis that provides adversaries with a lot of new damaging information?
<sarang> (as opposed to, for example, the closed-set attack, which really gave marginal information)
<suraeNoether> there is no practical way i can answer that question, sarang
<suraeNoether> i'm telling you it's the worst-known traceability attack
<suraeNoether> i'm estimating how bad it is
<suraeNoether> that's my job right now
<sarang> Anything else of note to share from your side regarding recent stuff?
<suraeNoether> not with respeect to MRL, no
<suraeNoether> and i have an appointment i need to get to you guys, so.. peach out
<suraeNoether> imagine whirled peas
<suraeNoether> love you guys *smooches*
<sarang> Anyone else wish to bring up something they've been working on?
<hyc> if you're bothered by blockchain sync speed, get your hands on Optane SSDs
<OpenSorceress> Optane SSDs?
<sarang> I store the chain in RAM
<hyc> yeah http://www.lmdb.tech/bench/optanessd
<sarang> I build a new ASIC for each block that gets added
<hyc> Real Men store the blockchain in RAM :P
<sarang> Well, I'll officially adjourn today's meeting; thanks to all for attending
<sarang> Next week, same bat-time, same bat-channel