--- layout: post title: Logs for the Monero Research Lab Meeting Held on 2018-05-07 summary: Sarang work, Surae work, and miscellaneous tags: [dev diaries, crypto, research] author: el00ruobuob / surae --- # Logs **\** OK, it's time to begin **\** Welcome to everyone; hello **\** Hi! **\** Calling others: hyc suraeNoether anonimal endogenic binaryFate fluffypony luigi1111 luigi1113 rehrar[m] monerigo[m] gingeropolous dEBRUYNE **\** and many others no doubt **\** s/monerigo[m]/moneromooo **\** présent **\** I suppose we can discuss recent updates and such **\** I have been focusing on noninteractive refund transactions **\** it's surprisingly tricky to get right **\** The idea of whether or not to hide block heights has big implications on size and complexity **\** and also will affect the use of old outputs **\** Hey everyone, sorry I'm late (and not using my registered nick) **\** A good higher-level question is whether we insist that having refund transactions is enough of a priority **\** Hello fake suraeNoether **\** heh **\** \*enough of a priority to devote big plumbing-level changes **\** these questions have consumed me as the Whale consumed Ahab **\** and, like Ahab, I spend much time in the company of Starbuck(s) **\** gross **\** theRealSurae: what has consumed you lately? **\** it feels like there should be an easier way to hide amounts. Maybe worth mulling for some time **\** UkoeHB: other than commitments? **\** Hi **\** Yeah. Maybe a shift in perspective. Baseless intuition **\** what **\** Well, the current Best Way is homomorphic commitments + range proofs to ensure balance **\** I've been thinking about koe's reduced mlsag and how we might be able to batch-verify ring signatures with bulletproofs. and i've been speaking with a professor at clemson university about the possibility of starting a paid project for a grad student to invent a new elliptic curve with 2^255-19 points on it, or to come up with a similar sort of variant to secp256k1 **\** yeah, I think we are going to experience reduced returns in terms of hammering bulletproofs for improving our amount strucutres **\** theRealSurae: BPs to batch verify our current MLSAG scheme? **\** oh yea the curve order question you asked **\** so, i think it'd be really really helpful for both bitcoin and monero to have alternate curves **\** ohgod **\** other than that and the multisig dump I made the night before yesterday, this week has been consumed by editing papers for other folks. Koe and my old advisor and another document. lots of reading this week **\** What are your thoughts on refunds? **\** and thank you for that :) incredibly helpful **\** UkoeHB: any big changes to your excellent paper? **\** Well we found out monero doesn't even use borromean sigs **\** genBorromean should be genSAGs **\** Or something **\** SAG? **\** I've been thinking a lot about the refund structure with timelocks, and I'm trying to figure out exactly whether we have a novel "invention" in these refund transactions or whether tit is equivalent to a timelock+multisig situation **\** spontaneous anonymous group sig. Like LSAG but no key images **\** for range? **\** Yeah **\** Check ringCT.cpp genBorromean **\** Yeah I'm familiar with that code **\** It's 33% larger range proofs than a real borromean setup **\** ... i need more details about that, koe, if you don't mind... **\** heh **\** theRealSurae: big thing is non-interactivity **\** I don't need the recipient's cooperation **\** I'll see what I can do **\** thanks koe, i'm not in a rush on that though... **\** I want to remind everyone that I'll be mostly away from the internet from tomorrow until the 19th, with some intermittent access. **\** luigi1111: is this (genBorromean doesn't actually generate Borromean sigs) correct ? **\** yup have fun :). Vacation right? **\** i'm not the sort who can really put work down, but i'm trying, briefly. i managed to write up a skeleton of the unforgeability proof for multisig and hand it off to sarang to familiarize himself with the musig approach **\** Zcash is also coming up with their own curve so as to speed up the particular things they need to. I find it worrying if the trend is that every project cooks up their curve to suit their particular needs. **\** and, like I said, I'm communicating with some folks at Clemson **\** Yeah I've been revisiting the original musig paper **\** Not that I know of **\** binaryFate: why would this be worrying? **\** theRealSurae: 2^255-19 isn't the number of points **\** you are right, it's the group order **\** against the "don't invent your own crypto", and light years away from typical review process for curves **\** right? i misspoke **\** no, 2^255-19 is the prime field **\** I hear it's a kind of cake **\** Or that feeling when your leg falls asleep and you stand up **\** Group order is l **\** 2^252+blah **\** aaaanyway **\** i confess I tend to think of our group as a scrambled mirror image of Z\_q, despite addition of points not even landing on the subgroup. **\** So theRealSurae is working on unforgeability **\** I am figuring out if noninteractive new-output-style refunds are worth it **\** Other fun times? **\** binaryFate: yeah, I see that **\** binaryFate: do you have any information on the Zcash efforts? I wasn't aware of their work **\** binaryFate: eventually that curve, even if proven to satisfy our desired properties, will have to be implemented, and the dangers or crappy implementation are huge... but I don't think that should discourage research into new curves and new proof methods using isomorphic curves **\** yeah, I wasn't either. I thought it was just Blockstream looking for a variant of secp256k1 so far **\** oh i messed up - they are borromean ugh **\** that's a relief koe! **\** UkoeHB: what led to believe otherwise? **\** ^ **\** misreading code like a fool **\** thought this hash\_to\_scalar(L[1]) meant an array of hashes for each L[1], instead of a hash of the entire array **\** Good thing hashes aren't important to borromean sigs /s **\** If there aren't any other big topics to discuss, we could certainly return to refunds or previous topics **\** There were suggestions from luigi1111 that the refunds needed for payment channels would be possible purely w/ timelocks + multisig **\** will look for some link on the zcash curve thing. It's part of their roadmap to reduce overhead to generate z-transactions iirc **\** I do not see how that would be possible without interaction from both parties, or a third-party arbiter **\** I just want to mention that I'm working on preserving the integrity of outputs held by mining pools **\** But I'd love to be convinced otherwise **\** MRL corporate cheer! **\** sgp\_[m]: in response to the linking work? **\** It does require interaction at the start **\** right **\** it'd have to **\** So the recipient pre-signs for the refund? **\** I have a bit of other ZCash news. **\** sarang kinda, yeah. I don't have too much to mention now though **\** How does the network verify the spend of the originally-intended output? **\** sgp\_[m]: ok, keep us updated **\** I've contacted ehanoc re: the "transaction tree" python toolkit and we will collaborate to deliver that after I finish the scraping tool which moneromooo asked for. mooo, I'll be sending you results this week **\** sorry to interject **\** sneurlax: excellent! That'll provide good data **\** rehrar[m]: tell us? **\** sneurlax: that's fantastic news **\** ZCash wants to open a grant proposal jointly with a Monero community member (that'd be me atm) to donate a considerable sum of money to some FFS proposals. **\** What types of FFS do they want to fund? **\** how would that work? would you have discretion over donating the funds? **\** https://twitter.com/socrates1024/status/993252058923925506?s=19 **\** i'll almost always take free money if it's no-strings **\** Aw shucks, they like us! **\** that's... fantastic **\** Dunno. When next round of bp auditing funds? **\** We can out it up, raise the amount, and take out right away. Superior Coin also wants to help if you recall. **\** Perhaps we can also get subaddresses audited? **\** hmm **\** Yeah, was thinking of waiting until closer to the finalization, but I suppose there's little advantage if we can coordinate w/ OSTIF quickly **\** it seems like a lot of projects want to funnel their research funding through the Monero FFS **\** the harder we criticize them the more they like us... 10k$ is not that much compared to amounts raised typically anyway **\** It's a nice gesture of community spirit though **\** I think the best ones are the hardware wallet (which should work with Zcash iirc) and code audits **\** They're masochists binaryfate. If we criticize harder they'll give more. **\** A subaddress audit depends highly on the scope **\** The BP scope was narrow-ish **\** binaryFate: yeah, it seems like a largely symbolic thing, but also: they've been really encouraging me and sarang to encourage you guys to ask for grant money. **\** rehrar[m]: i should just take zooko out to a bdsm club in denver, see if they offer us six or seven figures. :P **\** In return , we can send them Monero stickers to put on their laptops. **\** something something meat market **\** meat meat something market **\ \** In return , we can send them Monero stickers to put on their laptops. <-- they have one at least, we've put one on zooko's back at CCC without him noticing **\** I'll be interested to see how the 10K is disbursed **\** sarang: Is the implication that it would totally be up to our discretion? that's sort of what i'm getting... **\** Zooko is a dude. **\** I chilled with him in Colorado. **\** Can neither confirm nor deny Verge dev there too. **\** What if we take the 10k, pay for a semester of a grad student working with some cryptographers to invent three new curves, a variant for secp256k1, a variant for x25519, and a variant for zcash's thing **\** tall order **\** maybe **\** sorry rehar **\** it'd guarantee that student would spend the rest of his time in grad school working on that sort of thing **\** which I think would be a valuable thing: seed the mind-virus among as many researchers as possible **\** They're not even asking for doing joint work with zcash stuff at this stage apparently. Would just channel to Monero topics entirely if possible. **\** Hi all. **\** Anyway grad student is a great idea **\** binaryFate: yeah, that's the inference I made **\** I'll talk with Miller. **\** See how he wants to do the grant proposal. **\** binaryFate: the problem then is picking the student/school **\** Funding grant money for school research seems cool. Pinning all the hopes on one grad student seems like a bad idea. **\** rehrar[m]: please do, maybe CC me... I can hook him up with at least two cryptographers at Clemson who may be interested **\** pwrcycle: yeah, you'd pick by advisor more than student **\** Maybe we can get some people to make a FFS that should have made one a while back in exchange for ZCash paper **\** Like dEBRYUNE **\** Then again, what use have gods for our petty currencies. **\** Btw having some sort of pulic call for the paid internship circulating in academic circles is as important as the thing actually happening, in terms of mind-virus spreading **\** Nothing more from me. **\** rehrar[m]: you are the greatest orator of our time **\** binaryFate: TRUE point **\** very true **\** sarang **\** yo **\** when I get back I'm going to look into putting job postings on mathjobs.org **\** i was about to ask you to do it while i'm gone, but it's not urgent and there's no need to delegate. :P if you're curious, though :D **\** I think using mathjobs is a really good idea for pure math applicants **\** there are lots and lots of applied jobs on there too **\** you should check it some time, but **\** creation of a curve is at the intersection of applied algebraic geometry and pure cryptography **\** right, that wasn't what I meant **\** so it's sort of both pure and applied **\** oh ok **\** I mean to get solid reach to academics **\** that's the obvious choice **\** yep **\** They can send us a list of all the points on their new curve, for us to check **\** good old emails circulating between labs and advisors ("if you have a really good students, consider asking them to apply. And please forward blabla") is also worth it. Reaches more senior people than a job posting probably read primarily by students directly. **\** Oh, so I've been seeing random reddit postings about deep reorgs **\** But I haven't looked into it at all **\** Anyone know anything? **\** also articles are starting to come out https://www.trustnodes.com/2018/05/07/monero-allegedly-attack-claims-double-spends-orphaned-chains-21-block-deep **\** I think it's fixed now (no PR yet). **\** Do you know the cause? **\** is it known what the issue was? **\** jinx **\** The +20-blocks fork mentioned in the post is not an actual fork, you only see that when syncing. But somebody is fiddling with decent HR **\** buy me a DietMonero **\** i thought the first few reports were possibly the OP for some reason **\** moneromooo link or summary? **\** Some init wasn't done in some cases when adding a tx. **\** Yeah, I want to be able to give correct information **\** So that was causing the tx to be rejected though it is valid. **\** hrmm **\** OK, so that explains the "double spend" FUD **\** The long-chain reorgs are just related to initial sync? **\** It was noted that there wasn't any big spike in hashrate **\** so it's not outsiders coming online and futzing **\** If a pool doesn't accept a valid tx, it will continue mining on its own chain till it stops doing so. **\** OK, so it's a single cause with these two effects? **\** What two effects ? **\** Well the reports I've seen have complained about apparent double spends (rejected tx) and long-chain reorgs **\** i feel like if a selfish miner was going to release a chain in an attack, the hashrate wouldn't necessarily look different to an observer, especially if the attacker had 33%+ attack power and was clever with their timestamp choice... **\** I don't know anything about double spends. **\** Though if a merchant is only connected to that pool, you could swindle it. **\** The merchant would have to be only connected to that pool though, but that's not a new attack. **\** Yeah that's just being cavalier **\** https://www.trustnodes.com/2018/05/07/monero-allegedly-attack-claims-double-spends-orphaned-chains-21-block-deep **\** i don't like that article for a variety of reasons, but **\** Yeah that's the article I keep getting linked to **\** it's based on some r/monero complaint posts **\** so naturally it will be accepted as gospel and spread widely **\** it would be helpful to get more information from the specific users making this complaint **\** A random user says one thing and the devs who know things say another thing! So there's no way to know! **\ \** It was noted that there wasn't any big spike in hashrate <-- if someone is purposefully mining on alternative blocks rather than winning chain, we would not "see" the HR spike as it does not make blocks coming faster **\** You'd see a hashrate spike downwards. **\** only if that miner was mining before no? **\** Yes. **\** not necessarily; an attacker with exactly 50% hash rate and honest timestamps will appear to be invisible. an attacker with lower hash rate could mess with timestamps slightly and appear invisible. an attacker with too low of a hash rate couldn't manipulate his timestamps enough to hide his activity **\** (not necessarily re: downward spike) **\** Can we check how long it took them to mine a particular altchain of N blocks by checking logs on other nodes on when the last block in their chain got known to peers? **\** we can put a bound on it, for sure, and we can use that to estimate the hash rate power they have **\** ok y'all I gotta go **\** have a good week and a half! **\** same!