--- layout: post title: Logs for the Monero Research Lab Meeting Held on 2019-07-29 summary: Sarang work, Surae work, and miscellaneous tags: [dev diaries, crypto, research] author: el00ruobuob / sarang --- # Logs **\** OK, let's begin **\** Hello all **\** Logs of this meeting will be posted to the GitHub agenda issue afterward **\** GREETINGS **\** greetings! **\** hey **\** Whoops, here is the current agenda: https://github.com/monero-project/meta/issues/377 **\** Let's go ahead with ROUNDTABLE **\** I've been working hard on an RCT3 implementation, integrating some nice optimizations and seeing if it's possible to get key images working as expected **\** This also led to a bunch of other library updates that the code relies on **\** So generally just a lot of coding **\** I also gave a fun lecture on the Enigma cipher machine and the math behind it, which is always fun ;) **\** nice, what was that for? a meetup or something? **\** A friend teaches at a university and thought it would be good for an undergrad crypto class **\** Since the Enigma break is all about permutation groups **\** nice **\** I should be able to finish up an integration of the BP inner product verifier optimization into RCT3 shortly **\** Then, of course, DEF CON approaches! **\** neat **\** i have a very dirty branch on my computer with my matching simulations and experiments being worked upon **\** How are those going? **\** defcon - anyone got grasshopper repellent? **\** -\_\_\_\_- **\** i've proven all the theorems necessary to prove that the algorithm in graphtheory.py does what i claim it does, and i'm currently testing that my simulated ledgers are doing what i expect. **\** noice **\** Will be very neat to see the results, and to see if/how they can work with the analysis that Isthmus et al. are doing on Monero and Zcash **\** in addition to that, i have a bunch of MAGIC stuff I need to get done, and my discussions with isthmus' digital forensics work are leaning in that direction **\** i'm thinking the content of this project may take up more than two papers :\\ **\** Cool! **\** Also worth noting that the CLSAG paper has been updated on IACR, thanks mainly to kenshamir[m]'s comments and questions **\** kenshamir[m] has also been working on a Rust implementation of CLSAG/MLSAG using the dalek library **\** hyc: i hear grasshoppers are delicious, i wonder if any of those fancy vegas michelin star restaurants are capitalizing on the swarm **\** Anything you'd like to share on that, kenshamir[m] ? **\** Hi, the library is finished, not interopable with monero because it uses a different curve though. The numbers are quite impressive and I believe it is due to the way cLSAG was created **\** aw shucks **\** Will be great to see your MLSAG vs CLSAG numbers at different ring sizes **\** i believe there was a question re: ristretto and multi-exp like pippenger right before the meeting that would be relevant here? **\** I brought it up a while back because we handle different linear combination sizes \_very\_ differently in the codebase **\** is that rust code in a public repo? **\** We use no fewer than 4 methods **\** The numbers above were for different ring sizes, I may have mis-typed key sizes by accident **\** 256 and 512 were for the decoy sizes; if I was not clear **\** A big part of the reason CLSAG verification is faster than MLSAG is because of the introduction of a new linear combination evaluation algorithm **\** kenshamir[m]: can you link them again for the logs? **\** (if comfortable having them public) **\** \ Not the cLSAG code, once I add documentation and sanitise it I can post it in here **\** ty **\** \ Yep sure **\** :) **\** What does "without Pippenger/Straus" mean? Simple iterative evaluation of linear combinations? **\** Yep exactly **\** Impressive numbers **\** Of course, it's a different hash function **\** I just did scalarbase mult in a for loop **\** haha yeah that too **\** hmmmmm **\** But if the hash function is the same across both of your CLSAG/MLSAG, then the relative numbers are good **\** something that is both faster and smaller and with equivalent security is a no-brainer for implementation (pending audits) **\** Speaking of this, still in contact with potential auditors, who are moving very slowly **\** Nothing to report on that front :/ **\** the improved space allows for a logarithmic increase in verification time without actually slowing down the network (at least when it comes to new nodes downloading the network). judging by these numbers, a ring size of 16 or 32 is no longer like pouring molasses or concrete onto the network **\** OK, any other interesting research to report? **\** re: audits, or roll-out in general. Is this the kind of thing that could be rolled-out in parallel with existing? i.e., have an overlap, where the network uses the existing as the primary / default, but can optionally use the new thing, and then once new thuing is vetted, just prune the old? **\** ^ slow auditors - a lot of people are on summer holiday now **\** or, switch to the new and no longer have to relay / verify the old style during the overlap? **\** sarang: am i wrong in saying that gingeropolous is correct that clsag could be implemented in parallel before mlsag is deprecated? **\** we had a 24hr overlap in the last hardfork for this sort of thing **\** this would be kinda different. **\** I suppose it could be overlapping, provided the fee model supports it properly **\** I don't really see why this would be useful **\** i dunno. i'm just opening the conversation regarding the model that all new things need to be audited **\** i mean, obvi auditing is great **\** yes **\** but its not perfect **\** hyc: Yeah in general, summer constitutes low activity **\** It's good for inspiring confidence, as well as the obvious benefits of catching any errors **\** Can Monero benefit from using bulletproofs for arithmetic circuits? **\** gingeropolous: Didn't we discuss that kind of model for Bulletproofs or RingCT too? **\** Likely not, with our current tx model **\** yeah dEBRUYNE **\** The scaling isn't great **\** I think it was shot down for good reasons, but I cannot remember them exactly :-P **\** i think that was post audit though **\** and we have hash functions, which screw things up **\** Zooko had a slide in some presentation where his team estimated the verification time for a circuit with the complexity of Sapling (Sprout? don't recall) **\** and BP verification was O(1 s) **\** Compared to our current verification time which is probably 1/50th of that **\** maybe 1/100th **\** yikes **\** kenshamir: if we designed an arithmetic circuit to describe a ring confidential transaction language, then yes, but that's sort of what RCT3 and omniring and lelantus try to do... sarang, i think zooko was showing "what it would look like for a Sapling transaction language to be proven in the bulletproof setting" not ring confidential transactions, so it's not clear to me whether it'd be slower. **\** in our setting **\** with the exception of our non-AC-compatible hash function **\** sarang: That's verification time for fully shielded transactions? **\** dEBRUYNE yeah, iirc **\** Yikes **\** Yeah, that timing was just to give an example of what a production-size tx circuit might look like **\** Especially given that, as far as I know, you have to run a full node in order to properly perform fully shielded transactions **\** Anyway, I digress :-P **\** Anyway, suraeNoether is right in that RCT3 and Omniring try to bring the BP benefits to specific languages used to prove RingCT-type statements **\** which is why we're interested in them **\** yeah, bulletproofs for use in SNARK-style languages is like... uhm... putting a large-diameter turbofan engine into a Mini Cooper. It's not going to do what you think it's going to do. **\** BPs can be much more efficient for languages built for it **\** which is why range proofs are so efficient **\** haha **\** indeed **\** moving along **\** heh **\** ok, other research? **\** Or QUESTIONS, from the agenda? **\** OK then! To ACTION ITEMS **\** I'll be finalizing some things for my DEF CON talk, workshop, and panel; and finalizing some RCT3 integration optimizations **\** suraeNoether: ? **\** oh gosh sorry **\** i was computing a number sorry about that. :P **\** it's 7 **\** my action items are: work on sims and the experimenter, and work with isthmus to formalize statistical hypotheses for testing all this **\** Having data from Isthmus's group will be extremely valuable for this kind of analysis **\** actually the number is O(153.58\*N), which is the number of bits used to describe the number of possible spend histories at ring size 32 with N outputs. **\** which is nutters **\** This is all assuming no external information? **\** Or other graph-based information on chain reactions and provably-spent outputs? **\** merely the total number of self-consistent spend histories **\** Ah ok, so for a hypothetical graph **\** yeah **\** got it **\** O(153.58\*N) ... great. now your math is talking in math **\** well it means that for, say, 1000 transactions at ring size 32, there are 2^(153,580) possible spend histories. **\** anyway **\** (N has to be a lot bigger than the ring size for the above formula to hold btw) **\** which is... quite reasonable **\** Any other final thoughts or questions before we adjourn? **\** OK then! Thanks to everyone for participating. We are adjourned