--- layout: post title: Logs for the Monero Research Lab Meeting Held on 2018-11-12 summary: Sarang work, Surae work, and miscellaneous tags: [dev diaries, crypto, research] author: el00ruobuob / surae --- # Logs **\** howdy everyone! **\** meow **\** :D **\** hiyo **\** Sup! **\** hiyo **\** .....to quote sarang **\** so, let's flip the usual order of the meeting to allow for questions at the beginning **\** i like that **\** in fact, i'm going to call THAT the new "usual order" **\** 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 **\** roger **\** so, someone give me and sarang your top two questions :D **\** any updates on Konferemco preparations? **\** I should have a logo and branding guidelines today **\** in regards to MRL, where are we in the churn and privacy formalizations? **\** although I assume this will be talked about with your report of the week suraeNoether **\** that is precisely the case **\** i'm in the midst of getting hard numbers for a timing for a practical attack **\** 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." **\** this is a very useful metric, but it's dangerous to misinterpret it **\** Let us shift that to the later agendum **\** 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 **\** agreed **\** nioc our conference organizer has been checking out a few alternative venues, and we have already identified some vendors for things like catering **\** I have a question... how the hell do I build the dalek bulletproof rust implementation for timing testing??!?!?!?! **\** I know jack shiz about rust **\** that's an excellent question that occurred to me yesterday afternoon! **\** they claim to be bonkers fast, even compared to libsecp256k1 (which seems nutso to me) **\** they are claiming some mad speed gainz on top of your already mad speed gainz **\** They don't have batch verification yet tho **\** (it's on their issue list) **\** jfc **\** So I want to run timing tests myself to see **\** if that's the case, then... man that implementation is bonker fast like what-what **\** I don't think they're lying, but I'm also naturally skeptical **\** I don't find it terribly relevant since we're already pretty fast **\** i suspect that bulletproofs are going to benefit from 40 years of optimizations in linear algebra and ECC very very quickly **\** and any changes specific to underlying curve architecture aren't useful for us ATM **\** sarang: what if it's so fast it can reverse the blackchain continuum? **\** somethign to look into **\** Ah yes, the chain shrinks over time **\** negachain **\** the blackchain continuum hypothesis, by tom clancy **\** or dan brown **\** Anyway, it won't build for me, but I'll verify timings once I get it figured out **\ \** Ah yes, the chain shrinks over time <-- it will give extra space to your computer when it goes negative **\** However, they also have ideas for non-power-of-2 stuff, which was on the back burner for me **\** if it proves useful for them in a way that translates to us, great **\** 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 **\** nice **\** Also our other conference FFS (Stanford) was funded recently, so many thanks on that front **\** in general: thank you to all contributors who make Monero Research Lab a funded thing **\** suraeNoether and I will learn next month if either of us will be speaking there **\** anyway, other questions for us? **\** ne **\** In the absence of further questions, we can talk recent research **\** This past week, I did two events in Chicago **\** one was a hands-on Monero development workshop **\** the other was a more general talk on privacy tech **\** both videos are on YouTube, linked from the Monero Moon posting **\** thanks to the Chicago Bitcoin and Open Blockchains group for hosting me **\** Did you have a good time? think you'll do something like that again? **\** Yeah, I think it was very valuable **\** They had good turnout and excellent questions **\** I really like the workshop idea especially **\** 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 **\** what was the demographic of the crowd like? **\** The workshop was smaller (due to scheduling shenanigans for some participants) but had folks interested in math/CS/development **\** The talk had a good mix of technical folks and well-wishers **\** It'd be cool to find a way to host an interactive online workshop **\** what would that entail? **\** Well, one set of tasks I had them do was use a simple Python ed25519 library to build some constructions **\** like Pedersen commitments and Schnorr sigs **\** lol, love the name OpenSorceress. That's funny. **\** So being able to do video w/ slides for introductory work would be good **\** as well as interactive stuff to help the participants write code **\** Then we did some basic RPC stuff **\** like remote pairing? **\** OpenSorceress: some situation where the workshoppers could do in-browser code, perhaps, and then let me assist interactively if needed **\** I don't know if there is such a thing already **\** just spitballing here **\** that is pretty awesome, sarang! i'm glad it's online. **\** there is **\** orly **\** yeppers **\** -> floobits pops to mind **\** Cool, let's discuss after meeting **\** :) ok **\** I've also been working to integrate stealth addresses into the RTRSRingStringRuffCT optimizations **\** and other minor tasks, etc **\** allrighty **\** How about you suraeNoether? The graph matching, perhaps **\** well, i've been doing the churn and graph theoretic stuff **\** 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 **\** It's worth noting that this isn't even new analysis **\** But a really clever interpretation of older stuff that suraeNoether came up with **\** which is always great in math **\** correct, in fact several of these were proposed right around the time Bitcoin was proposed, which amuses me **\** 2007, 2008, 2009 **\** so are you saying that as the blockchain gets larger, anonymity decreases? **\** well, consider the following situation **\** let's say something ridiculous like "tomororw Monero goes back to ring size 1" **\** 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" **\** what happens? a bunch of blocks are added to the monero blockchain, all of which are totally linkable **\** this is an edge case of the following idea: **\** Even I could link them! **\** heh **\** if we take our present system and add a bunch of non-anonymous stuff, we aren't improving our anonymity **\** in fact, we are decreasing our anonymity, by essentially diluting our nice big fat blockchain filled with fat ring sigs with non-anonymous data **\** At their heart, these metrics use numbers of matchings to relate to some idea of anonymity **\** a graph matching is a possible global spend history, of which there will be many **\** Think of it as being a guess about true spends that's at least \_consistent\_, but of course not provable **\** 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 **\** however **\** what suraeNoether was saying about it being useful to examine proposed changes is a good idea **\** So you can say "if we increase ring size to X given usage patterns Y, this metric implies that anonymity gets better" **\** it's not possible to say things like "anonymity gets Z% better" though **\** 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?" **\** the fact of the matter is, though, it very slowly changes with respect to graph size at these levels **\** got it **\** to maintain an EAL similar ot what we have today, the blockchain could be 10x larger **\** and we might need a ring size of like 15 at that point, or something like that, to make it equal exactly **\** I have the same types of broad, non-mathematical questions about global anonymity that I do about rings in general **\** 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 **\** sarang actually we can sort of answer that question quantitatively **\** 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" **\** and that depends on how your legal system works **\** What types were you considering? **\** 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. **\** we may be able to quantify our security on an individual level that way, and see how it is sensitive to game parameters **\** anyway, 100% of my MRL attention is on this paper right now **\** 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 **\** Subtly moving from "not provable spending" to "not heuristically-guessable spending" seems like a generally good idea, but it's like swiss cheese **\** all of my work so far is highlighting, essentially, the urgency with which we need to replace ring signatures **\** true **\** and the fundamental problem with using KYC exchanges **\** Well, those aren't going anywhere **\** and if anything, more people will move to them **\** as opposed to DEXs? **\** Do you know of any usable ones? **\** I assume Bisq works **\** bisq .. ? **\** haven't used it **\** question on replacing ring signatures...is there any sort of tech (eevn un battle tested) that exists at the moment? **\** nor have I **\** rehrar: no **\** i hear bisq is good, but i haven't used it yet **\** rehrar: yes and no **\** not without sacrificing trust **\** or speed/efficiency **\** correct **\** there are some trustless set-ups that are unreasonably slow **\** if we could do cross-chain atomic swaps with BTC that would eliminate a huge chunk of exchange usecases **\** or big **\** IMO the goal of the graph matching analysis should be to at least get an order-of-magnitude estimate on Monero global spend histories **\** 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 **\** I'm not convinced this provides an adversary with remarkably more actionable data than existing heuristics **\** how would you go about sussing that out? **\** 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 **\** it should provide literally the same amount of data, just one is a global approach and one is a txn-by-txn approach **\** OpenSorceress: run the analysis on at least a portion of the chain **\** suraeNoether: implementing nipopow is a huge undertaking **\** yes **\** suraeNoether: what do you see as the goal of the analysis? **\** provide actionable advice for the monero community on how to mitigate the worst known traceability chainalsysis attack. ultimately **\** in terms of ring size specifically? **\** given that the EAL is sensitive to it? **\** not necessarily, although that is presently a facet of the analysis, yeah. **\** 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 **\** What's the takeaway from all of this, for the folks in this meeting? **\** research is ongoing into the matter **\** progress is being made in terms of making actionable recommendations to the community **\** but we aren't announcing them yet, until after more consideration **\** i'm not sure what you mean **\** good enough for me **\** Do you view this a fundamentally new form of analysis that provides adversaries with a lot of new damaging information? **\** (as opposed to, for example, the closed-set attack, which really gave marginal information) **\** there is no practical way i can answer that question, sarang **\** ok **\** i'm telling you it's the worst-known traceability attack **\** i'm estimating how bad it is **\** that's my job right now **\** ok **\** Anything else of note to share from your side regarding recent stuff? **\** not with respeect to MRL, no **\** kk **\** and i have an appointment i need to get to you guys, so.. peach out **\** imagine whirled peas **\** etc **\** np **\** love you guys \*smooches\* **\** Anyone else wish to bring up something they've been working on? **\** crickets! **\** if you're bothered by blockchain sync speed, get your hands on Optane SSDs **\** yeah? **\** Optane SSDs? **\** SSDs? **\** Ds? **\** ?? **\** **\** I store the chain in RAM **\** yeah http://www.lmdb.tech/bench/optanessd **\** LOL **\** I build a new ASIC for each block that gets added **\** Real Men store the blockchain in RAM :P **\** Well, I'll officially adjourn today's meeting; thanks to all for attending **\** Next week, same bat-time, same bat-channel **\** ttyl **\** bai