--- 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 **\<suraeNoether>** howdy everyone! **\<nioc>** meow **\<OpenSorceress>** :D **\<sarang>** hiyo **\<TheFuzzStone[m]>** Sup! **\<rehrar>** hiyo **\<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 **\<sarang>** roger **\<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>** agreed **\<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) **\<suraeNoether>** jfc **\<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 **\<sarang>** negachain **\<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>** nice **\<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? **\<rehrar>** ne **\<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 **\<sarang>** orly **\<OpenSorceress>** yeppers **\<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 **\<suraeNoether>** allrighty **\<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>** heh **\<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>** however **\<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 **\<sarang>** true **\<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 **\<sarang>** correct **\<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 **\<suraeNoether>** yes **\<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 **\<sarang>** ok **\<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>** ok **\<sarang>** Anything else of note to share from your side regarding recent stuff? **\<suraeNoether>** not with respeect to MRL, no **\<sarang>** kk **\<suraeNoether>** and i have an appointment i need to get to you guys, so.. peach out **\<suraeNoether>** imagine whirled peas **\<suraeNoether>** etc **\<sarang>** np **\<suraeNoether>** love you guys \*smooches\* **\<sarang>** Anyone else wish to bring up something they've been working on? **\<sarang>** crickets! **\<hyc>** if you're bothered by blockchain sync speed, get your hands on Optane SSDs **\<sarang>** yeah? **\<OpenSorceress>** Optane SSDs? **\<endogenic>** SSDs? **\<sarang>** Ds? **\<endogenic>** ?? **\<OpenSorceress>** **\<sarang>** I store the chain in RAM **\<hyc>** yeah http://www.lmdb.tech/bench/optanessd **\<endogenic>** LOL **\<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 **\<hyc>** ttyl **\<rehrar>** bai