Auditing Strategy for zkEVM

foreign [Music] security and how can we be convinced that the CK AVM implementations that we're all working on are secure so today I'm joined by Hai Chen who works with scroll Tech and has been like leading engineering there about implementing the ckvm I'm with Jordy Molina who's who's part of the polygon Hermos team and has been leading engineering there one thing that strikes me about like the organizations of polygon and scroll is that their their willingness to collaborate they've both been like big collaborators in in Xerox Park and I'm now exploring like how to security kvms together I'm also joined by David who's on the ethereum foundation security team and has a traditional background in in security and and all its and things like that so I hope that today we can have a nice kind of exploration of how we're going to be able to make the ZK VMS that we've been working on secure so that's my first question how can we how can we secure the ckvm how can we secure the ZK evm yeah so yeah hello everyone I'm hijin so I think like so the zqm is a very complicated circuit so to actually make sure like the uh to make sure that the decayment is secure I will definitely need to go through like the all several auditings like having Auditors to look at look at the circuits and probably I think like maybe not even like a one single team of Auditors maybe have multiple teams look at that again I can uh and then we can like find some bugs and then we can fix that and then after that I think we also should do like the like on Parallel can do some bug Bounty program which like have like the more community members who like the interesting to looking into this stuff and then finally they find any box I'll Attack those things uh that's nice thing like that to have that's more secure uh and then last I think maybe a little bit like to say like have some more Advanced Techniques like the very nice people and other people like to describe have some more formal verification tools and then Frameworks do like a model checking those kind of stuff also like I think like initially maybe it's more scalable to a very large circuit but I think we can eventually get you there yeah that's like my maybe just to complement that and first of all uh open source you know that's probably the first step in in securing something uh cryptography bifurcation or just you know probably cryptography this this has the humanity already has been tested that this doesn't work we have experience Microsoft Google IBM so big corporations that just pay a lot of money just uh building private cryptography systems we know that this is not the way to go we need as many A's as possible of all kinds to take a look at the at the code at the protocols and that's why it's the first so the first must this is not enough but the first is that this needs to be open source and the the people and especially the users have to have uh access to this code this is the the first step okay and from now on let's start as as he says is is is it's a complex system so the first thing is the first problem that we are challenging is that uh who can review that because it's something that's new it didn't exist before we are creating a lot of Primitives a lot of you know direct meditation all the uh because we're doing a lot of tricks and a lot of things and there is no experience on that side so the first thing is who's going to review that who's going to take a look who has the capacity uh to to to to look at that so first step and this is where we have started the partnering here together just to that is to uh to somehow uh start teaching start uh explaining uh straight into the Auditors explaining to the community explaining to anybody that's interested in the system this is the first so this is this is for sure it's the first step if because we need to open and the first the open even if it's open source if nobody can understand what's in the in that repo it's like being closed source so so we need this to to open and to explain to teach to spread how we are where we are working and and and and and Publishing that and this is the the the next step after that so when we have this let's say minimal uh um minimal you know minimal um critical mass of uh Auditors and and so on next step is okay then here is how we organize okay so we organize the the auditing and because we need to be here a little we need to talk about procedures and we need to talk about how we specifications how we write the good specifications how we can split these specifications and uh have them in the procedures how can we clean the code how can we uh go and this is this is going to be the problem the the next step and once we have this clear we have this specification phase quite clear that the things is quite clear then it's a matter of uh just taking a look and even that we will never have the warranty like any cryptographic system we will never have the warranty that the system is going to be 100 safe here uh we have the responsibility as projects to invest as much as possible in resources uh at least in the polygon side I'm sure that in of the other projects too they will not launch anything until they feel uh comfortable enough that the system is reasonably safe um David do you have any comments with it uh yeah uh I think so I think open source multiple audits um I think education is important the for me coming from like a traditional security research background um I think we have very strong software security research capabilities in the community I think that there's uh you know there's multiple components here there's like the L1 verifying contracts and as you've seen in previous talks you know three or four years ago we didn't really we just knew what it re-entrancy was because uh the big Dow hack now we have like 101 best practices for solidity coding so we have like these different components um pillars to stand on unfortunately with security uh it's kind of the weakest link issue here so um like we've got a great bug tracker for ZK stuff but I kind of where I see like a large gap is that we have a lot of academics um that come from like a formal verification or like a mathematical uh background and then we have these people that understand like implementation so it's great to one like multiple audits but we don't really have multiple firms that know how to audit so the education stuff is like critical here some of the tooling stuff is reusable with like uh formal verification but I think like over time it's going to be about this collaboration um I think that this is like critical I think you know you can look at some of these things and say like hey all these l2s are competing and I'm not sitting I'm you know I work for the EF and I care about systemic things um so I'm not like on an l2's team here um but in the long run like you could say oh yeah it's a zero-sum game for these l2s but if something catastrophic happens to any of them I guarantee you it's a like a it's a positive sum in the negative direction for everyone nobody is going to trust billions of dollars on TBL here and they're all just going to go to optimistic Roll-Ups right so I think this approach here I see polygon zkevm folks in the crowd I see all these people working together and Xerox Park kind of like hosting this community where academics can come together I think that this is kind of the the only path forward because it's the only missing thing that we have here um that that we don't have some like tried and true testing methodology and so I don't think this is anything new for the blockchain uh Community the prereq requisites to understand smart contract security require you to understand decentralization things like oracles all these New Primitives and so we've had this already we've seen people tackle things where you have to not just be an expert in like one domain like software security you have to understand Economic Security and all these things or the whole system falls apart so I think this is just going to be an evolution and I think that there's like we're on the correct path uh forward thank you thank you David um so the ZK VM is a is a very complicated piece of software it has many components and those components interact with each other my next question is like what components are you all specifically worried about what's what what keeps you up at night uh yeah I see like this so there are multiple pieces it's like in the uh ZK even circus so it's not like uh so you know architecture is not only one single circuit so it's actually a set of circuits that connects with each other and then so work together to uh to suddenly like verify the evm behaviors correctly that the trace is correct so I think like that first of all like the most important piece is like the the original the evm circuits which is the most like Central piece so it's kind of like the uh your model like the the evmr codes and then all that state transitions correctly so those kind of things like I think uh so I think like the people usually I can know how to do like that so uh integers like big integer multiplications and then our integer additions but like if you need to be true like that all of the constraint is very true to what evm specs it does like they will assume yellow paper defines how evm works there's a lot of like the corner cases if you look into the details so those are kind of cases they usually will be easily overlooked so I think that's like the one thing that's very important to do to check and then the second thing is that so that because the circuits need to work together then you connect to some lookup tables uh to to be sure and then certain things like maybe checking one circuit and a certain property will be guaranteed by another circuit uh then how can we guarantee that this like the combination of all the circuits is a sound and a complete the ones like to check everything that you have inside the event uh to fully guarantee or does Decay even is correct so I think this is the kind of two biggest things like that I think it would be uh important to to auditor that you can even so so like you're saying that like the two big issues are the corner cases and the interfaces between the different components yeah yeah nice okay yeah I agree I think that makes sense kind of maybe a different architecture uh on that so probably the pieces are different on that side here I would say two parts one is the what we call it the ROM or if you one is the the code that actually implements the evm itself there is a lot of lines of code and this is like it's like writing a smart contract you know it's it's at the end a single uh mistake in one of the lines can screw up everything and and this is well this is concerning this is because it's it's it's critical code and if you see that number of lines that are in there are a lot actually is you can imagine Geth but Brighton in assembly you know it's just it's it's a complex code there okay so this is probably my biggest concern that is fine and then there is that in meditation in Orchestra limitation is is probably much more simple uh because at the end we have just a kind of a processor there so the Logics is more in the wrong part but uh but it's not a lot it's a very new language it's a very new thing it's something that uh we don't have experience designing identity polynomial identities on that side so and it's very very easy to to to miss some something or don't take in account something and and so on so probably these are the two things that are more concerned but I cannot forget you know even the smart contract that I'm there and then more things that are more uh basic if you want but they need to be safe too right I I find that there's this misunderstanding in the space where people equivocate like L1 to L1 Bridges with L1 to L2 Bridges and I I I think that it's the problem is that they call it even Bridges no I I would like to go back to the double pegging for for chain to chain and and this is maybe it's a bridge but it's a truthless breed it's it's just a smart contract just it's a mechanism to moving funds but it's not what we understand as uh classical breach of you know just a kind of a multi-seek where you need to draw some some party yeah absolutely so so to be clear L2 bridges are much more secure than L1 Bridges hopefully um yeah so I think I think like this kind of just like points to a lack of like true terminology everybody's marketing right now um so I would say like L2 Bridges I would call them fast Bridges where there's like a third party and they're taking the risk so if there's a double spend on one of these Bridges like the person that's getting the one percent uh fee for transferring your you know off of an optimistic role than letting you not take the seven day wait period or between two ZK VMS or whatever like they they get a yield and they take the risk and they're the ones that's like you know out of luck if something happens um for me like I'm not sitting here thinking like what's the like worst doomsday scenario uh for my ZK evm um I'm thinking like what happens to eth when something bad happens to zika evm and I I hate to say it but like something bad is gonna happen we've seen double spin bucks in Aztec we've seen them in um Z cash we've like these things are a big deal the one thing that's like the Saving Grace for ethereum here is that we have a native non-privacy like token standard at the base layer and the reason this is important is because you can see when there's insolvency in a contract whereas if you just had like the ZK uh like roll up and this is your entire ecosystem and everything is either private or it's using ZK to scale you might not know that somebody's printed Infinity tokens or that some other wallet has negative tokens and that's like how your constraints add up and so for me it's like this lack of transparency here I think that there's some like traditional security um like philosophy that we can apply here you can do things like have like buckets and I understand like if you're trying to do something like scale this isn't that big of a deal if you're trying to do something like staying private having buckets for like your your like zero knowledge cash type transfers like you can think of like tornado cash that it reduces the anonymity set so like there are some issues here but there are also things that we're starting to see now um where you might have like a withdrawal like we do see these like chain to chain bridges that aren't really Bridges um they maybe can have like a uh like a Floodgate mechanism like if somebody's gonna drain the entire contract that's probably not normal when there's a hundred thousand users that are using your L2 so like if 10 of the contract exits in a 24-hour period maybe having like these kill switches um will be good and then you can do things like have guarantees where if there is an issue everybody takes a 10 or a 20 haircut on their TBL and nobody's left holding like the complete Miss like like lost bag I do think though that like you know if there is something systemic and like a like a multi-billion dollar uh zkevm gets basically drained and this is a problem then at least the base layer of ethereum is like still there and and we can still make those like trust and rebuild and so for me the like the scariest part here is the new technology I mean people were afraid they they people don't really understand like the zero spin problem until they see that like Bitcoin has gone up over time and like well yeah there's nothing behind it there's all this stuff but there's somebody willing to buy it from you right now for twenty thousand dollars right and so over time people like start to trust these things and I think of like if you guys have seen the Indiana Jones where he's like stepping on the like different pieces and like one of them falls through or like if you're crossing a creek you kind of want to like feel the rock that you're going to put all your weight on before you go I think that that's going to be the same thing here we're gonna have to like have people start to trust you know the cryptography that they don't understand yet like this is all Moon math to the average person right even like Advanced security Engineers don't understand any of this stuff and so there's this gap between the understanding of like you know this this like high level multi-dimensional Matrix math that you guys all understand and then like the people that like know what like a traditional software bug looks like and so that Gap right there is the is the scariest thing and the lack of transparency if something goes wrong is is also scary to me but you know you can mitigate some of that risk by bucketizing and these other things I've mentioned I I think that like what resonates with me about what you were saying was how it's really nice to have this L this roll-up Centric roadmap so that we're able to experiment with these new things and we're able to build systems that with time can can get the kind of trust that we need cool so my next question is like so when I do all this what I normally do is to I try to find things that like people don't know or that the developer didn't know when they were writing the code so what are some of the things that people don't know about about like your code or things that could be interesting for people to pay attention to um yeah I think that's a good question it's like I'm not sure like that you hear audits what other stuff that's like the when they do like other teams but I see like there'll be things like I think behind like the foreign tricks and then that could be make the circuits like less readable uh which like the I think Auditors may find like that's very uh hard to understand certain part of the logic of the circuits so I think that seems like we should explain uh those kind of things uh to the to the Auditors um and I think in addition like there's some certain assumptions we make like doing certain uh part of gadgets or part of the circus like you make certain assumptions and I think those things like a very important like maybe only the developers who develop those circuits knows about that but I think you need to those also seems like important to put down into specs so that the audits can know like the why you're doing certain things in a while like you're not doing sentences yeah there are many things but uh one one that's important and the concern is that from what we have in in the in the in the program it's a non-deterministic so it's not deterministic here it's not anonymizing means that first of all you want to do a division actually what you do is you put the result and then you check the the multiplication okay and tricks like that uh well there are many for example one when we are where we are scanning transactions actually where we are doing if we are hashing all the transactions but we are putting all the data all this data is we call it free input okay and then we are uh we have a constraint that calculates the hash some call and then the hash is the public that's actually what needs to be matched okay but you can put anything in there it's okay because you have to Hash but this kind of um this is something that for a normal programmer for a normal um normal drummer something exchange it's something that's not used to it's something that's different and this needs to be explained very well we seems this we have seen for example internally in the team you know in the team maybe it's just the people that just learn things as people that you know they come from uh other backgrounds and uh it's natural that uh what you first write these programs and you do a lot of mistakes because you don't have uh you're deleting absorb this concept of course you repeat that you do it again and and then the people is getting but it's something that needs to be explained very well because uh I think this could be one of the big sources of uh problems in there I I actually don't have any real good input for this question so leave it there thank you um my next question is how can traditional tools help us when we're trying to secure the KVM uh yeah let me just start with like one more simple things it's like setting everything to zero CFL can pass that's like in a lot of cases you can pass again which is not correct in your circuits so that's like one simple scenes and another thing like uh some basic scenes like a fuzzing so I think like the inner zero noise stick I think the first thing could be like slightly different you know like buzzing arbitrary data that's putting inside your circuit with this that's it's very easy you don't like that the uh that like that it won't pass the proof because like it's there's lots of constraint checks you need to be very careful to make some Corner cases to make sure like the there's some invalidancings that you put into the circuit but then can pass that but I think like in the context of the eke ebm is that you can generate arbitrary Trace like that you can you can fast the trace of the the from the evm NSC like that's uh if that can pass it I think like that's like the what Paradise was just like talking about like those buzzing other people very helpful like to to use like generate some value trades and some invalid trades and then just and then you can tweak a little certain small amount of things like inside the trace to make things like the uh that should not be passed by if they pass the circuit then there's some bugs inside yeah in general all these formal verification tools uh with maybe with some adoption with some adoption specifics but can be used at least to to to understand better some parts of the circuit maybe not like everything but there are specific pieces that are quite clear and that work very well or that can work very well uh with this tooling I'm thinking for example they are in Matic extend machine in our case this is very clear you know it's very metic you know this must be a multiplication and cannot do anything else this is something that for my application people love to see this this clear patterns uh in there so I'm sure that some work can be done and there if you go to the main processor that's it's not that mathematically well defined maybe there they have more uh more problems and that here is more free physiologically make more sense but uh yeah definitively you can can can help and here maybe it's a caller for people that's expert in in some it's it's good to understand and to see how this this thing works because I'm sure that there is a lot of tooling and a lot of these things that can be very helpful and we are and we don't even know that those tools exist so here is uh it's important for the community to be productive here the Xerox Park people is doing a great job on that and there is people that's already looking at that and there are some ideas that things can be done in there uh that's important again it's just explaining because when you when you really understand the circus when you really see what the disease you you can find people that's expert in that material that that can see ways to that can help a lot um I think so formal verification has been mentioned uh formal verification and it's like I can only do so much in like a regular security testing and so it just so happens that there's like so much math in these circuits here um that it just lends really well to this so I'm I'm really excited about that um first of all it's like the first time I think I've seen it applied in a way where I'm like well this is going to be a big part of my life I need to go read you know brush the dust off of all the textbooks another thing is that there's like a lot of there's like a lot of traditional things um with security audits that that actually lend well to to these also and like a good example would be like typing like strong typing is is serious and regular security you have integer underflows you have integer overflows you have casting errors things can flip negative and you see this in these circuits but you also see like um there's sometimes optimizations and developers do this stuff naturally um a good example is like the Aztec 2.0 uh maybe was not ever exploited but what was reported there was like an input that was 128 bits or 64 bits and the actual constraint was only 32 bits so you could actually provide multiple nullifiers if to pass all the constraints which means you could potentially like withdraw from Z cash type thing more than once even though you only deposited once and that is something that is queryable and you can just have a strong typing system so like the a correct static analysis tool that was that like could have could have been applied to that and just said hey error manual like review required this input over here is a larger is a different type than this like the way it's used and casted over here so anytime there's like a casting error you can have this I think there's going to be like plenty of other queryable examples like this where we can apply traditional security tools towards this cool um so where do we need to make new tools to like Lucas talked earlier about his exploration of trying to make a polynomial solver and like there seems like there's a lot of scope for us to explore like where would you like to see new tools yeah I think like uh so a lot of tools like I mentioned I found traditional like formal verification they are not very ready I think for the uh proving that the uh the the ZK like the circuits so I think like those things like will be very good to have and then I think like not only like some tools like from the like for auditing I think that there's more tools will be uh very useful from the proof system side it's like they can provide you a very easy to use interface to uh generate some arbitrary like the uh error cases like you can inside the circuit and also have a very um bug reporting for example where does the circuits fail and those kind of bug reporting will be also very important tools a second auxiliary uh make the auditing and then make the testing like the more easier and then easier to find some bugs yeah clearly these uh back reporting we launched the test net the public test net on on Monday we already got a report of uh never was nothing crazy but it was already a buck that we already fixed it and that was because we published that and somebody just tested and we just put something there so this is the importance of uh testing the things and I agree the the bug reporting is is when you see something that goes wrong you need to investigate until the last and fully understand what's going on because you probably you have something that can be getting worse um I think a formal specification for differential fuzzing would be really cool um I think that there's like a value add when you could take like 10 different zkevms and you could potentially throw a test case at each of them and then you can compare the output States afterwards um I think the value out here is everybody wants to be part of it because you're going to know that you're conforming to the spec if you know if your output matches everyone else's this has been incredibly fruitful with our consensus Slayer clients in ethereum for the beacon chain so we have five clients there's certain things that are in the spec like processing an Epoch transition and so we can hand it Like Us form it's a it's a specified beacon block object and we can run it through every one of them and we can diff all the outputs afterwards and that's like incredibly valuable right like that's uncovered multiple bugs it would be like chain splitting bugs and these types of bugs like in the L2 world would mean that you'd have a state diff between the L1 and the L2 which means double spins it means all kinds of other like horrible things can happen um another thing that I think is really important is uh like zoomed out from the ZK ABM it's more like about L1 contracts in general and that's like a like an open security standard of like ahead of time hey if you're a white hat and you find a bug please report it to us obviously like we'll resolve it privately but there are some cases in the security world where like a vulnerability primitive drops and everybody hears about it at the exact same freaking time and like when that happens you've actually seen this like be fruitful where white hassle front run black hats they'll steal all the money out of the contract and then they'll return it like and you know maybe get a bounty or whatever and so having like a previous specified like okay on your bug Bounty page have a little thing down there that's like yo if if you guys drain a billion dollars a tvl from my contract this is how much the white hat Bounty is and uh we're like legally saying you're off the hook ahead of time if you return it all and you do all this kind of stuff and we are seeing some of this stuff kind of come out and flush out in like the D5 ecosystem there's gonna be like a spec that's being working with worked on right now with the open security standard or Alliance or something like that I think there'll be more information about this like in a few months I think this is all just kind of like in the community right now but I think that's going to be huge because if you know ahead of time I know a lot of like white hats that they just don't want to touch stuff like this so there was like uh I think it was like The Nomad hack a bunch of people were able to just replace like the public key to receive funds and replay the attackers uh original like exploit and they were all like a bunch of white hats stepped up and started draining this contract and it was weird you can only drain like a little bit at a time so they were able to like actually recover a certain amount of the funds and you know it sounds weird to say like Hey we're going to give you a White House Bounty if you hack our contract and steal all of our crap but this is like a phenomenon that keeps reappearing where everybody hears about the vulnerability at the same time and we do need people to drain these contracts ahead of time so like that's one example of something like that um thank you David yeah sorry to interrupt yeah um so my last next question is like um the harder one so when would you all feel comfortable to put all of ethereum's assets inside your ckvm yeah that's a tricky one so I think like that so when we launched a Mainland I see that it would be assumed like that's audited and that would be like very happy to do that for myself yeah we have the experience of Hermes one and other you know other real production life and yeah it's a hard decision uh General I I look at the Ace of the people that audit uh that and it's who audited that and I'm talking the specific guy I don't care about the the brand and it's just the guy and and even the kind of uh questions that the auditor made uh how deep they went and uh the experience that this person have when you put all these pieces together so it's just but you need to know personally like each of the Auditors each of the internal and external Auditors and each person of the people you just check to all the places and uh here is just a feeling it's it's a feeling that okay this is uh this uh should be reasonable safe that's a feeling it's not uh I wouldn't it's difficult to put a parameter because what you say you say oh we need two of these we need three of these we need four persons three persons it's really it's really hard because this person's now I see now this I pay it out it's that I'm sure that the guys that made the audit they didn't check the smart contract at all and I've seen that okay so it's not so okay we have two Audits and and I'm not gonna I'm not I'm not gonna trust depending on the who made the Outreach okay so that's it's more personal thing it's personal people who made what what the questions they did what scan it where they went and this is when you you I would feel comfortable but it's a very personal decision it's a very uh uh feeling decision so it's it's hard uh to the answer all of ethereum's assets I say never um I think I think the zika evm for L1 will be good for having like statelessness and being able to think of like client instantly without having to download all the trends and all the transaction history I think there's like value there but I think just like everything else here um time is the thing that like makes you trust it people trust uniswap because uniswap has a natural bug Bounty of billions of dollars sitting in it right now anyone can go after it so like time will tell the analogy of like kind of stepping and feeling the rock I think that's important but I think that like bounties are are a big deal and and these things naturally have bounties um open source is important you need lots of eyes but shell shock and Heartbleed were in the Linux kernel for like how long I mean every for 10 years every single like 75 of the computers connected to the internet had an arbitrary kernel read and nobody knew about it right somebody was probably using that the whole time so for me like you know this stuff is very new ecdsa tried and true like sure BLS like we we we took some like we can do this because we want to aggregate signature years and the trade-off was important but we're not putting ZK in the consensus layer right now for a reason and this is like I mean I sat in a backyard with vitalik and and Dan Binet and you know this guy's been doing ZK stuff since the 70s when nobody cared about it um and now we're heading to Golden Age of cryptography and we're implementing it and he was like I wouldn't I wouldn't put in the consensus layer so we're taking baby steps in the consensus layer ssle so that we can prevent um we can have privacy about who's proposing next so they can't DDOS like targeted DDOS our proposers and proof of stake that's like the only place we're taking a tiny little baby step a ZK um I think beyond that everything else is there's a reason you have like this there's no privacy and like like ZK scaling in the in the layer one and I talked a little bit about contract solvency I think that like my golden future for ethereum is that all nation states are issuing their cbdc's and they have their privacy they have their kyc all these things in their ZK roll up and then we can all say like yep the US government actually has something to back up their reserves right which is something that's a benefit on our current system if we didn't see the M1 and M2 money chart and if we even trust that we don't actually know how many dollars are out there because nothing's backed by gold anymore so I think there's a reason I think there's always a trade-off I think anytime you take a bridge whether it's ZK or it's an optimistic roll-up you end up inheriting the risk of all of the pieces there whether it's the fraud proving or anything and I think that people will do things like like uh have their their large company or their large corporation or their large government having their financial reserves being completely visible on the L1 contract and then all the fun scalable private stuff we can do with ZK we do on top of that and and we take the risk trade-offs the same way that you have a bank account and you have the cash in your wallet thank you David um I think I only have time for one more question uh so my last question and hopefully we can go through this quickly is uh what's your favorite security bug uh yeah it's like uh my very secure bug is like the I think previously for the Z cash they have like The Trusted setup like and then they put like in one extra additional points to there which like allow people to do like an infinite like uh counterfeit some C cash tokens on top of that and then that was like but it wasn't fun for like many years until like every like found out that I thought you said that's a very epic One Security work in general or specific to the to the IVM that we're building in general I can I can I can tell you the intern the the the internal one this is the Luna but it's it's I think it's a good example of this bag that we actually found but this is a good example that is okay we found it it's back but you know we couldn't vote for sure you know I tell you it's like in the sparse Mercury there is a condition some point at some point there is a condition that you need to check that when you are deleting that uh the key you need to check that the key that the keys is to say that that's not the same key that there is a so there is a check that you need to do that um we didn't well the first implementation the check was not there and when I saw that is it's so easy to forget that check it's so easy that's when you realize how complex this is this is and this was fun by well but by the person that was documenting the was documenting the the this part of the storage but if if it sees this what else can be in there and this is the this is the the the the the concern and and the landmarks um I have like a million favorite bugs so I'll say the ZK specific ones I I think that the uh the like lack of auditability because of the Privacy that ZK inherits here is just really cool uh I mean you see these L1 contracts get hacked and like Twitter's excellent at like broadcasting information and like this like distributed Network way where if you follow somebody like you can like infosec Twitter I know about bugs wait before potentially developers do because like it just gets spread so fast and you cannot see a D5 protocol get hacked now and not know in like 30 minutes if you're keyed into crypto and infosec Twitter um I think it's really cool like that a hacker could like basically steal all the funds slide out the back door and nobody would know for like years potentially because of ZK I think that's just really cool cool um thank you everyone thanks for taking the time thank you thank you [Applause]