Logs for the Monero Research Lab Meeting Held on 2018-05-07
May 07, 2018
Logs
<sarang> OK, it's time to begin
<sarang> Welcome to everyone; hello
<sgp_[m]> Hi!
<sarang> Calling others: hyc suraeNoether anonimal endogenic binaryFate fluffypony luigi1111 luigi1113 rehrar[m] monerigo[m] gingeropolous dEBRUYNE
<sarang> and many others no doubt
<sarang> s/monerigo[m]/moneromooo
<binaryFate> présent
<sarang> I suppose we can discuss recent updates and such
<sarang> I have been focusing on noninteractive refund transactions
<sarang> it's surprisingly tricky to get right
<sarang> The idea of whether or not to hide block heights has big implications on size and complexity
<sarang> and also will affect the use of old outputs
<theRealSurae> Hey everyone, sorry I'm late (and not using my registered nick)
<sarang> A good higher-level question is whether we insist that having refund transactions is enough of a priority
<sarang> Hello fake suraeNoether
<theRealSurae> heh
<sarang> *enough of a priority to devote big plumbing-level changes
<sarang> these questions have consumed me as the Whale consumed Ahab
<sarang> and, like Ahab, I spend much time in the company of Starbuck(s)
<theRealSurae> gross
<sarang> theRealSurae: what has consumed you lately?
<UkoeHB> it feels like there should be an easier way to hide amounts. Maybe worth mulling for some time
<sarang> UkoeHB: other than commitments?
<rehrar[m]> Hi
<UkoeHB> Yeah. Maybe a shift in perspective. Baseless intuition
<silur> what
<sarang> Well, the current Best Way is homomorphic commitments + range proofs to ensure balance
<theRealSurae> 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
<theRealSurae> yeah, I think we are going to experience reduced returns in terms of hammering bulletproofs for improving our amount strucutres
<sarang> theRealSurae: BPs to batch verify our current MLSAG scheme?
<silur> oh yea the curve order question you asked
<theRealSurae> so, i think it'd be really really helpful for both bitcoin and monero to have alternate curves
<theRealSurae> ohgod
<theRealSurae> 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
<sarang> What are your thoughts on refunds?
<UkoeHB> and thank you for that :) incredibly helpful
<sarang> UkoeHB: any big changes to your excellent paper?
<UkoeHB> Well we found out monero doesn't even use borromean sigs
<UkoeHB> genBorromean should be genSAGs
<UkoeHB> Or something
<sarang> SAG?
<theRealSurae> 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
<UkoeHB> spontaneous anonymous group sig. Like LSAG but no key images
<sarang> for range?
<UkoeHB> Yeah
<UkoeHB> Check ringCT.cpp genBorromean
<sarang> Yeah I'm familiar with that code
<UkoeHB> It's 33% larger range proofs than a real borromean setup
<theRealSurae> … i need more details about that, koe, if you don't mind…
<sarang> heh
<sarang> theRealSurae: big thing is non-interactivity
<sarang> I don't need the recipient's cooperation
<UkoeHB> I'll see what I can do
<theRealSurae> thanks koe, i'm not in a rush on that though…
<theRealSurae> I want to remind everyone that I'll be mostly away from the internet from tomorrow until the 19th, with some intermittent access.
<moneromooo> luigi1111: is this (genBorromean doesn't actually generate Borromean sigs) correct ?
<UkoeHB> yup have fun :). Vacation right?
<theRealSurae> 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
<binaryFate> 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.
<theRealSurae> and, like I said, I'm communicating with some folks at Clemson
<sarang> Yeah I've been revisiting the original musig paper
<luigi1111> Not that I know of
<theRealSurae> binaryFate: why would this be worrying?
<luigi1111> theRealSurae: 2^255-19 isn't the number of points
<theRealSurae> you are right, it's the group order
<binaryFate> against the "don't invent your own crypto", and light years away from typical review process for curves
<theRealSurae> right? i misspoke
<vtnerd> no, 2^255-19 is the prime field
<sarang> I hear it's a kind of cake
<sarang> Or that feeling when your leg falls asleep and you stand up
<luigi1111> Group order is l
<luigi1111> 2^252+blah
<sarang> aaaanyway
<theRealSurae> 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.
<sarang> So theRealSurae is working on unforgeability
<sarang> I am figuring out if noninteractive new-output-style refunds are worth it
<sarang> Other fun times?
<theRealSurae> binaryFate: yeah, I see that
<sarang> binaryFate: do you have any information on the Zcash efforts? I wasn't aware of their work
<theRealSurae> 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
<theRealSurae> yeah, I wasn't either. I thought it was just Blockstream looking for a variant of secp256k1 so far
<UkoeHB> oh i messed up - they are borromean ugh
<theRealSurae> that's a relief koe!
<sarang> UkoeHB: what led to believe otherwise?
<luigi1111> ^
<UkoeHB> misreading code like a fool
<UkoeHB> thought this hash_to_scalar(L[1]) meant an array of hashes for each L[1], instead of a hash of the entire array
<sarang> Good thing hashes aren't important to borromean sigs /s
<sarang> If there aren't any other big topics to discuss, we could certainly return to refunds or previous topics
<sarang> There were suggestions from luigi1111 that the refunds needed for payment channels would be possible purely w/ timelocks + multisig
<binaryFate> will look for some link on the zcash curve thing. It's part of their roadmap to reduce overhead to generate z-transactions iirc
<sarang> I do not see how that would be possible without interaction from both parties, or a third-party arbiter
<sgp_[m]> I just want to mention that I'm working on preserving the integrity of outputs held by mining pools
<sarang> But I'd love to be convinced otherwise
<rehrar[m]> MRL corporate cheer!
<sarang> sgp_[m]: in response to the linking work?
<luigi1111> It does require interaction at the start
<sarang> right
<sarang> it'd have to
<sarang> So the recipient pre-signs for the refund?
<rehrar[m]> I have a bit of other ZCash news.
<sgp_[m]> sarang kinda, yeah. I don't have too much to mention now though
<sarang> How does the network verify the spend of the originally-intended output?
<sarang> sgp_[m]: ok, keep us updated
<sneurlax> 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
<sneurlax> sorry to interject
<sarang> sneurlax: excellent! That'll provide good data
<theRealSurae> rehrar[m]: tell us?
<theRealSurae> sneurlax: that's fantastic news
<rehrar[m]> 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.
<sarang> What types of FFS do they want to fund?
<theRealSurae> how would that work? would you have discretion over donating the funds?
<rehrar[m]> https://twitter.com/socrates1024/status/993252058923925506?s=19
<theRealSurae> i'll almost always take free money if it's no-strings
<sarang> Aw shucks, they like us!
<theRealSurae> that's… fantastic
<rehrar[m]> Dunno. When next round of bp auditing funds?
<rehrar[m]> We can out it up, raise the amount, and take out right away. Superior Coin also wants to help if you recall.
<rehrar[m]> Perhaps we can also get subaddresses audited?
<theRealSurae> hmm
<sarang> Yeah, was thinking of waiting until closer to the finalization, but I suppose there's little advantage if we can coordinate w/ OSTIF quickly
<theRealSurae> it seems like a lot of projects want to funnel their research funding through the Monero FFS
<binaryFate> the harder we criticize them the more they like us… 10k$ is not that much compared to amounts raised typically anyway
<sarang> It's a nice gesture of community spirit though
<sgp_[m]> I think the best ones are the hardware wallet (which should work with Zcash iirc) and code audits
<rehrar[m]> They're masochists binaryfate. If we criticize harder they'll give more.
<sarang> A subaddress audit depends highly on the scope
<sarang> The BP scope was narrow-ish
<theRealSurae> 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.
<theRealSurae> rehrar[m]: i should just take zooko out to a bdsm club in denver, see if they offer us six or seven figures. :P
<rehrar[m]> In return , we can send them Monero stickers to put on their laptops.
<sarang> something something meat market
<theRealSurae> meat meat something market
<binaryFate> <rehrar[m]> 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
<sarang> I'll be interested to see how the 10K is disbursed
<theRealSurae> sarang: Is the implication that it would totally be up to our discretion? that's sort of what i'm getting…
<rehrar[m]> Zooko is a dude.
<rehrar[m]> I chilled with him in Colorado.
<rehrar[m]> Can neither confirm nor deny Verge dev there too.
<theRealSurae> 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
<sarang> tall order
<theRealSurae> maybe
<endogenic> sorry rehar
<theRealSurae> it'd guarantee that student would spend the rest of his time in grad school working on that sort of thing
<theRealSurae> which I think would be a valuable thing: seed the mind-virus among as many researchers as possible
<binaryFate> 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.
<pwrcycle> Hi all.
<binaryFate> Anyway grad student is a great idea
<theRealSurae> binaryFate: yeah, that's the inference I made
<rehrar[m]> I'll talk with Miller.
<rehrar[m]> See how he wants to do the grant proposal.
<theRealSurae> binaryFate: the problem then is picking the student/school
<pwrcycle> Funding grant money for school research seems cool. Pinning all the hopes on one grad student seems like a bad idea.
<theRealSurae> rehrar[m]: please do, maybe CC me… I can hook him up with at least two cryptographers at Clemson who may be interested
<theRealSurae> pwrcycle: yeah, you'd pick by advisor more than student
<rehrar[m]> Maybe we can get some people to make a FFS that should have made one a while back in exchange for ZCash paper
<rehrar[m]> Like dEBRYUNE
<rehrar[m]> Then again, what use have gods for our petty currencies.
<binaryFate> 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
<rehrar[m]> Nothing more from me.
<theRealSurae> rehrar[m]: you are the greatest orator of our time
<theRealSurae> binaryFate: TRUE point
<theRealSurae> very true
<theRealSurae> sarang
<sarang> yo
<theRealSurae> when I get back I'm going to look into putting job postings on mathjobs.org
<theRealSurae> 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
<sarang> I think using mathjobs is a really good idea for pure math applicants
<theRealSurae> there are lots and lots of applied jobs on there too
<theRealSurae> you should check it some time, but
<theRealSurae> creation of a curve is at the intersection of applied algebraic geometry and pure cryptography
<sarang> right, that wasn't what I meant
<theRealSurae> so it's sort of both pure and applied
<theRealSurae> oh ok
<sarang> I mean to get solid reach to academics
<sarang> that's the obvious choice
<theRealSurae> yep
<sarang> They can send us a list of all the points on their new curve, for us to check
<binaryFate> 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.
<sarang> Oh, so I've been seeing random reddit postings about deep reorgs
<sarang> But I haven't looked into it at all
<sarang> Anyone know anything?
<selsta> 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
<moneromooo> I think it's fixed now (no PR yet).
<sarang> Do you know the cause?
<theRealSurae> is it known what the issue was?
<sarang> jinx
<binaryFate> 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
<sarang> buy me a DietMonero
<theRealSurae> i thought the first few reports were possibly the OP for some reason
<binaryFate> moneromooo link or summary?
<moneromooo> Some init wasn't done in some cases when adding a tx.
<sarang> Yeah, I want to be able to give correct information
<moneromooo> So that was causing the tx to be rejected though it is valid.
<theRealSurae> hrmm
<sarang> OK, so that explains the "double spend" FUD
<sarang> The long-chain reorgs are just related to initial sync?
<sarang> It was noted that there wasn't any big spike in hashrate
<sarang> so it's not outsiders coming online and futzing
<moneromooo> If a pool doesn't accept a valid tx, it will continue mining on its own chain till it stops doing so.
<sarang> OK, so it's a single cause with these two effects?
<moneromooo> What two effects ?
<sarang> Well the reports I've seen have complained about apparent double spends (rejected tx) and long-chain reorgs
<theRealSurae> 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…
<moneromooo> I don't know anything about double spends.
<moneromooo> Though if a merchant is only connected to that pool, you could swindle it.
<moneromooo> The merchant would have to be only connected to that pool though, but that's not a new attack.
<sarang> Yeah that's just being cavalier
<theRealSurae> https://www.trustnodes.com/2018/05/07/monero-allegedly-attack-claims-double-spends-orphaned-chains-21-block-deep
<theRealSurae> i don't like that article for a variety of reasons, but
<sarang> Yeah that's the article I keep getting linked to
<sarang> it's based on some r/monero complaint posts
<sarang> so naturally it will be accepted as gospel and spread widely
<theRealSurae> it would be helpful to get more information from the specific users making this complaint
<sarang> A random user says one thing and the devs who know things say another thing! So there's no way to know!
<binaryFate> <sarang> 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
<moneromooo> You'd see a hashrate spike downwards.
<binaryFate> only if that miner was mining before no?
<moneromooo> Yes.
<theRealSurae> 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
<theRealSurae> (not necessarily re: downward spike)
<binaryFate> 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?
<theRealSurae> we can put a bound on it, for sure, and we can use that to estimate the hash rate power they have
<theRealSurae> ok y'all I gotta go
<theRealSurae> have a good week and a half!
<binaryFate> same!
Post tags : Dev Diaries, Cryptography, Monero Research Lab