Topic: Sidechain Observer - Bitcoin L2 Projects & current state of development (Read 644 times)

I looked a bit into Botanix Labs' Spiderchain project, as I recently heard news about its adoption by a major DeFi player (Aave). Spiderchain is still a testnet, but gets regularly mentioned, also on more seriously/academic-looking websites, so it might be worth a look. It is EVM-compatible.

On their documents on the website, Botanix describes their project as a "distributed network of decentralized multisigs safeguarded by a randomized subset of participants". Another claim: "Anyone will be able to stake their bitcoin on Bitcoin."

Spiderchain nodes are called Orchestrators. Orchestrators need to deposit a certain amounts of coins, which will be slashed when the orchestrator misbehaves. Orchestrators hold Bitcoin multisig wallets. Every Bitcoin block a new multisig wallet is created and assigned to a random number of orchestrators.

So far the design resembles Nomic and tBTC, but with a difference: on the sidechain, there seems to be no native token. This means, the deposits and also the PoS staking are all done in "sidechainBTCs". This raises questions about potential risks if the sidechain's supply changes drastically, however this problem should be similar in other concepts like Drivechain.

The deposit/withdraw process of the first version is described here, although not in the detail I'd liked (incentives, risks). There is also a centralized server, the SideCar, involved, which "helps" users with peg-ins and peg-outs. According to the docs however this is an early version and would be decentralized further over time.

So far this concept seems interesting above all because no pre-mined token is involved and thus it seems to combine the advantages of Liquid and Nomic/tBTC. Once its mainnet gets launched I will probably investigate it more deeply.

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Sorry to respond late to this. According to BitcoinLayers, Fractal's bridge is managed by a single, centralized custodian (Bool Network) and the code of the bridge is not even open source. So basically it's not better than Liquid.

There is no new development for Gelios, I think people find out already and that's part of the reasons why the volume keeps going down, the team are not reachable anymore too, I believe they abandon the project already.

One provides seemless integration and infinite scalability with Bitcoin, and this one uses the Bitcoin core code outta box for unlimited layer scaling, still pretty new and the reason why I find this one better is the fact that it gained attention.

Since its launch now many Bitcoin miners have moved over 30% of mining power to this L2 project, because it is a PoW coin just like Bitcoin too, I don't think that many people are aware of this new kid on the block yet.

The name is Fractal Bitcoin.

I don't know much about Bitcoin Layer-2s and will dedicate time in the coming days to absorb as much knowledge on Bitcoin Layer-2s as much as I can. I'm really hoping that Bitcoin doesn't following the same path that Ethereum took when they made Layer-2s, the focus of their roadmap, neglecting Ethereum itself and that is beginning to hurt their community. I do not wish for such for Bitcoin but I'm very happy that builders are building on Bitcoin now more than ever.

Thanks, I've watched the video. Basically he's saying that the team disappeared, there were suspicious transactions, and that there are connections to other projects like Xally which could indicate they were created by the same "team". If I interpret correct even BVM could also be implied - this is another project I consider very doubtful, and as I wrote in my review it's interesting that in the whitepaper there are sections which look very similar to the Biop whitepaper. Perhaps another candidate?

Edit: The video is about a month old, so maybe there are new developments now. The Gelios price on Coingecko meanwhile is lowering every day  

So I've added Gelios to the "possible scams" list, with the video linked as the accusation.

I want to clarify here however (have added that "disclaimer" to the OP too) that I'm more interested in the technical side of the projects here in this thread. It's not a scam busting (or L2 promoting) thread. But anyway I'm thankful for all links and other material about possible scam accusations as, as I wrote in the OP, a lot of those "L2" projects listed on l2.watch for example are looking very, very shady. And they don't exactly contribute to sidechains becoming more interesting for the average Bitcoiner.

It is more than you could have imagined, Gelios team are responsible for building few other scam projects too, if you don't mind looking into it then here you go..

https://youtu.be/pml2X7vL76U?si=JiwdKbxQn1lYZG44

Also, someone on the forum already created something similar in the altcoin discussion section weeks ago, I think this accusation are too clear to doubt, although many people fell victim already.

Thanks for your opinion, can you link to the YouTube video? I've not found it, but there seem to be still some promotional videos about them.

I have already stated that Gelios didn't leave a good impression on me, if it's an outright scam it would be not surprising for me. I've added a warning to the post where I reviewed them but more context would be nice


My opinion about Merlin Chain is not that positive, although certainly a bit better than Gelios, and on BitcoinLayers.org they also have not really stood out among other semi-centralized projects. Thus it would be interesting why you think that they're worth mentioning, perhaps because of their proposed future ZK rollup mechanism?

I didn't know about Tectum, so thanks for mentioning it, I'll probably look into it.

I just want to correct a few people mentioning Gelios in this thread, that project is a proven scam project, go on YouTube and see for yourself, some smart members have exposed the project, and the team blocked them, as you can see the project volume is almost dead, there is a reason why.

The only real BTC layer2 projects that's worth mentioning are Merlin Chain and Tectum, these two are far from scam or any shady acts so far, there are many more but most are scams. Becareful where you put your hard earned money.

The majority of them won't survive, I will still choose most old BTC L2 projects over new projects, like Rootstock and Lightning.

While some in the "sidechain community" for sure are waiting for Stacks to rollout their sBTC bridge based on a dynamic federation (this should happen in October or November), I looked a bit deeper into tBTC, a "relatively" decentralized bridge. It is active on several chains, among them Ethereum, Solana, and the ETH L2s Arbitrum, Optimism and Polygon. An overview is here and the security model is described here.

Basically, tBTC (not to be confused with testnet Bitcoin) converts Ethereum, Solana and the other altchains it resides into a Bitcoin PoS sidechain.

The second version of the tBTC bridge, which I will describe here, was launched in early 2023, the first one (already launched in 2020) relied on overcollateralization and was thus a bit similar to algorithmic stablecoins like Dai.

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tBTC is a bit similar to Nomic (see this post) in that the stakers of a certain token, the T token (the "subnetwork" of this token on each participating chain is called Threshold Network), manage the so-called "wallets", which hold the Bitcoin funds which back the tBTC token.

Each wallet is managed by 100 so-called "signers", which are selected among the T token stakers with an algorithm looking a bit similar to the "Follow-the-satoshi" principle, i.e. each staker's chance to become a "signer" is determined by the amount they stake. 51 of these 100 signers have to collaborate (using Threshold Elliptic Curve Digital Signature Algorithm, an alternative multisig-like scheme) to move the Bitcoins in the "wallet".

Like in Nomic periodically (each 12 hours) the deposits on the Bitcoin chain are consolidated into a single UTXO, and once this occurs, tBTC are created on the altcoin chain (ETH, SOL ...). This process is called "Deposit Sweep". Due to it being slow, there's an additional mechanism called Optimistic Mint, where tokens can created already after 3 hours if an user group called "Guardians" doesn't prove the deposit was created fraudulently. It's very similar to an optimistic rollup.

To redeem BTC, the user notifies (via a smart contract called the Bank) the signers of a Bitcoin wallet (see above). This request starts a timer, and the signers now have to prove the tBTC user got the tBTC according to the protocol, and pay him out the equivalent amount of BTC on the Bitcoin chain. If the signers become unresponsive and somebody notifies the smart contract on this failure, the signers' stake deposits are slashed and the tBTC are returned to the user, who can (afaik) then start the process again. The user who notified the contract gets a part of the slashed reward, again a bit like in an Optimistic rollup.

The redeem process is slightly different than in Nomic, but in general the system is quite similar. In both systems, if you deposit a BTC, you basically trade Bitcoin's PoW security to a PoS system. I believe also Thorchain works with a similar model.

i think we have already had this discussion many times and you simply forget the basics

VALUE (economic number) is not PRICE
values(sentiment/desire) is not VALUE

bitcoins VALUE is not measured on the market. VALUE is a number that sits below the market price. much like retailers do not show the cost to the farmer of milk/butter. retail market price just shows the going rate to customers which is affected by values and other market effects
but underlying that is the wholesale, the value. which if the retail market comes down to near the value amount then the price is not at premium but near value

farmers cant/wont sell their milk/butter below cost and if the most efficient farm on planet can only make milk/butter at X, the retailers cant even get milk/butter for less so wont sell their retail market product below that value either.. hense it forms a support line no one wants to cross below

however if people can self produce for pennies, then it can sell for pennies and still break even.. so if the current price is exceptionally high premium compared to its self production cost. the only reason its held up high in the markets is due to the market affects of manipulation and thus has more chance to crash

..
when you mention looking at stats of how much coin is on market orderbooks waiting to be converted or is being converted today.. thats the stuff of the market effects of the swings values(sentiment) of the short term PRICE drama of whats ABOVE VALUE.

dont confuse value with price

I took a deeper look at the Nomic protocol to describe the incentives governing it here. Nomic is currently functional, but the sidechain functionality is limited to 21 BTC before an audit has been concluded. There is also a fork called OraiDex or OraiChain - they seem to be more active with development, but be cautious like with every new project

The whitepaper is here.

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Nomic is to my knowledge the most advanced project which has implemented a dynamic federation. This means: The sidechain is run by a set of validators which also operate a Bitcoin client and vote for every valid peg-in and peg-out. In the case of Nomic, the sidechain is controlled by a proof-of-stake algorithm, i.e. the validators are also probably those with most stake in the utility token. This makes the incentive structure easier than in merged-mined sidechains if we assume that the stakers are interested in their token's value (what Vitalik Buterin called once "altruism-prime"), but of course if this is not the case then the typical potential vulnerabilities of PoS consensus are also present in Nomic.

The Nomic stakers are also signatories of a multisig address called Reserve Wallet on the Bitcoin main chain. They have to pay a collateral which will be slashed if they misbehave. Via Schnorr signatures and MAST trees up to 1000 signatories can be supported in a so called reserve script controlling the coins. This set of signatories is regularly updated, see below.

Nomic signatories have to vote with a 2/3 supermajority for each transaction they carry out. The voting (through the reserve script) occurs in two ways: via a key path using the Musig2 Taproot multisig algorithm containing a "standard" set of signatories, or with a fallback script using a standard multisignature scheme, if one of the signatories in the key path becomes unresponsive.

How does this work in practice?

1. When a Bitcoin user wants to peg-in the coins (i.e. deposit coins on the mainchain to receive sidechainBTC), he transfers the BTC to the Reserve Wallet via a P2TR transaction with an additional OP_RETURN output containing the sidechain address the user wants the sidechain coins to be deposited to, and a timelocked "reclaim" scriptpath for the case the sidechain signatories are unresponsive, then the user can reclaim the funds after a number of blocks (144 are recommended according to the whitepaper).

The sidechain nodes build a deposit proof from the deposit transaction and publish it in the sidechain network. This will later enable the user who deposited Bitcoins create sidechainBTC on the Nomic sidechain.

2. When a sidechain user wants to peg-out, he builds a transaction on the Nomic sidechain burning the sidechainBTC and requesting withdrawal to a Bitcoin address.

3. Periodically, the signatories publish checkpoints on the Bitcoin main chain. This allows to process deposits, pre-process withdrawals and update the signatory set if the set of validators/signatories has changed on Nomic. Checkpoints are made of up to three connected transactions:

- Deposit Collection Transaction: The signatories spend all deposit utxos to a script containing the current sidechain reserve script. This transaction is only carried out if since the last checkpoint deposits have been made.
- Checkpoint Transaction: This transaction is always carried out, even without deposits. It collects the UTXO from the last checkpoint transactions and, if deposits were made, the UTXO from the Deposit Collection Transaction. The coins are spent to the Reserve script, and if withdrawals have been made, then a second UTXO is spent to which will pay out the withdrawals. The main purpose of this transaction is to update the set of signatories (stakers).
- Disbursal Transaction: This transaction pays out pending peg-outs or withdrawals from the second UTXO of the Checkpoint Transaction. It is only carried out if there were withdrawals since the last checkpoint.

In addition an Emergency Disbursal Transaction is signed, which would send the whole reserve to the current sidechainBTC holders. This transaction has a long Locktime. It protects sidechain holders from a "liveness failure", i.e. when the signatories become unresponsive for a long time. At the same time it slashes all collaterals on the sidechain, so the signatories are incentived to always create checkpoints regularly.

As far as I interpret the whitepaper, the Deposit Collection Transaction is still signed by the "old" set of signatories (where the depositors spent to), while from the Checkpoint transaction on, the reserve script contains the "new" set of signatories and these also sign the transaction.

I also interpret that after a deposit, the sidechainBTC will be created only after another checkpoint (more precisely: the Deposit Collection transaction) has occurred, to prevent the depositors to cheat, create sidechainBTC and then spending the coins of the "reclaim" script path (see above).

The peg-out process depends on the behavior of the signatories before the Disbursal Transaction is built. This means that, before voting positively for a withdrawal, the nodes have to check that the withdrawal request corresponds to a legitimate "burn" on the sidechain and that its ancestry is correct (this should of course be validated continuously by the PoS validators).

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At a first glance the scheme looks reasonable. It does not protect 100% from a liveness failure but as long as the PoS incentive process works correctly the sidechain should also work as expected. In the case of a liveness failure the coins will be returned and the signatories/stakers will be punished for that failure. This means that the system depends heavily on the Nomic tokens having at least some value to make punishing effective, but again, that is common to PoS systems. Another reason the utility token should be valuable is that otherwise the signatories could be contempted to "pause" their participation in periods with high Bitcoin fees (e.g. around Bitcoin's last halving).

The big con is, of course like in most L2 projects, the premine of the utility token NOM. However, at this moment the NOM token is not traded at any exchange, so it's not the typical pump and dump where the utility token is launched and dumped before the main functionality is added. And of course it's possible to think about a no-premine fork

Nomic also doesn't provide a tail emission for Bitcoin miners via merge-mining, a topic we discussed in several threads which could be a long term solution for Bitcoin's "Year 2140 problem". Possibly the protocol could however be changed in a way to make that possible, for example if the sidechain block "production" is changed to a PoW/PoS model.

I disagree here. I'll keep it short because it's OT in this thread: for me Bitcoin and all cryptocurrencies work like platforms (i.e. social networks). The mining cost is not very relevant for the value creation, it's usage and above all demand for the blockchain. If you want a "cost" to speculate on, I think the most convincing metric would be the volume of fiat/other assets being converted to Bitcoin without being immediately converted back ("new buy orders created", for example). So I actually don't see a big difference to PoS coins here.

Correct.

A short remark here: I guess there will be always an equilibrium between the coins "pegged into subnetworks" and those that "stay at the mainchain". And it will be always better to have several subnetworks, above all if we talk about sidechains.

If a subnetwork becomes too important without its underlying blockchain providing a convincing amount of security, this could lead into this subnetwork becoming an attractive target for attackers wanting to short Bitcoin (attacking the sidechain's consensus). So I guess that if millions of BTC are eventually locked into sidechains, we could see community action caring about no one of them becoming too strong, similar to what's currently occuring with mining pools (no one should come close to 50%).

We could speculate that this could even lead to the situation where already strong mainnets which have still some space for transactions could become attractive for "layer-2" mechanisms. This is for example the reason why I created a thread about the idea "Bitcoin on Litecoin" (until now, I conclude that it's possible but would require a lot of development work for the protocol). tBTC on Ethereum (pegged to wBTC) is another example, but Ethereum doesn't really have the capacity to accomodate all transactions of a full-fledged Bitcoin "subnetwork", i.e. working as Bitcoin sidechain. LTC would be a more convincing choice.

Yes, that's an interesting point. So actually I think Sztorc is too fearful of altcoins being able to "dethrone" Bitcoin.

If we talk only about "features" of the scripting language, Ethereum should have "dethroned" it already but that didn't happen. The market thus thinks that either 1) Ethereum's features are not that relevant and/or 2) Ethereum has some disadvantages with respect to Bitcoin. I think both things could actually be true. The disadvantages being, apart from Bitcoin's first mover advantage, the large premine, the not-complete censorship resistance (TheDAO rollback) and PoS as an inferior consensus system.

value/price/market cap flippening:
alot of people think blockchain currency units are created at no cost and so the market can speculate down to zero or up 'to the moon'.. much is true for PoS coins and other silly meme tokens that are based on nothing but drama. however bitcoin does have major cost of block/coin creation cost. the hashrate/difficulty vs mining cost gives bitcoin units real underlying creation cost value which the markets then speculate above, preventing it from going to complete zero(unless the hashrate/difficulty dropped)

for there to be a flippening where another network takes the top spot, it requires some real underlying cost security, meaning that a currency needs to push itself above the underlying cost of bitcoin or bitcoin loses a substantial amount of hashrate/difficulty to drop its underlying cost

currently ethereums cost of creation dropped by 95% when it changed to PoS and is only being held up speculatively by its conversion to bitcoin where traders on the bitcoin side are manipulating the ethereum price to keep ethereum speculative high compared to its cost value.
in short ethereum has alot more chances of crashing to near zero compared to bitcoin because its only due to bitcoin that ethereum is being held up so high

utility/usage/popularity flippening:
currently no subnetwork has more then ~6000 coin pegged so i dont see any subnetwork taking on the majority of usage/utility away from bitcoin.
as for other mainnets, which pretend to offer more/better/faster features, if you look at their market price movements, most just shadow follow bitcoins movements so there is little independent market sentiment separating other mainnets from bitcoin. they just shadow each other due to the arbitrage opportunities of bitcoin.
if we start to see things like ethereum become more price independent and less shadowing bitcoins whim, then it shows they are developing more independence, but for the moment i cant see a flippening happening where a different mainnet gets popular in utility/usage to go full independent and starts to be the dominant mainnet for crypto.. but with thats said, the future can change things

Well I hope you are right, but BIP 300/301 were already created in 2019, and the problem is that there are several high-profile developers skeptical about the concept. Unfortunately I have read no recent news about that to be changing.

Regarding shitcoins becoming useless and disappear, I really doubt it. The incentives for shitcoins aren't that much "that they offer something different" than Bitcoin. For example if you start a simple Bitcoin clone from 0, a lot of people could actually buy it only because they would even make a profit if the coin gets 0.001% of Bitcoin's market cap, even if all the difference is that it has a new genesis block. That's what happened with some of the first altcoins, namely Bytecoin (BTE), but you could say it even about LTC which managed to survive until today in the top-25 altcoins. There are lots of other coins out there having a lot in common, that's also true for the 999 "Ethereum clones". They'll never put Bitcoin's (and Ethereum's) leadership in danger, but they survive.

I think Sztorc's opinion there is of course directed to those that say that Bitcoin is "outdated" and there will be a "flippening", and in this case I somewhat agree.

The issue is that it is extremely easy to build a blockchain today. There are a lot of open source libraries. And then you add a centralized bridge and call it a "L2". Or directly clone Ethereum's Optimism rollup and add a wBTC bridge. That's what happened with most projects I've reviewed on the l2.watch website.

Not that this is bad per se, maybe somebody actually creates an interesting project. But a 50% premined "L2" with no convincing 2-way peg and only vague ideas how this could be decentralized is a no-go for me.

So many l2 projects without any real users. We already have lightning network and it still not wide supported, that's sad especially when you know how fast it is

It doesn't take years for Drivechain and most of the stuff is already ready to be deployed with BIP 300 and BIP 301.
Than you can create any sidechains you want, we could have actual privacy on bitcoin, and most of the shitcoins would become useless and dead.
https://github.com/bitcoin/bips/blob/master/bip-0300.mediawiki
https://github.com/bitcoin/bips/blob/master/bip-0301.mediawiki

Myself I'm not particularly fond of the "layer" buzzword. But it seems to be the most popular at this moment, more so than "sidechain".

And for me it's also different than a simple "bridge". Current "bridges" like wBTC are not tied strong enough to Bitcoin's consensus mechanisms as they often imply trust in some bridge custodian. In other words: if "wBTC" is a bridge, then I'd like another word for a sidechain or another mechanism where no direct trust is required, be it "layer" or whatever. L-BTC if we follow this definition is a bridge though, not a layer, due to the necessary trust in a Federation.

For a "layer" I would personally expect such a strong tie, like provided by mechanisms like Drivechain. I would tolerate however that the layer is based on a set of additional, but decentralized incentives. This means: a decentralized system external to the Bitcoin main chain which rewards custodians to play by the rules and punishes them if they don't, could be enough to classify it as a "layer".

If the "layer" is the contract dealing with the Bitcoin-pegged token (multisig federation etc.), the rest of the chain functionality not necessarily has to be part of the "layer". In my transaction-graph centric "layer definition" the chains are independent from each other. So a chain can without problems contain a "layer" to infinite mainnets. The chains are only the technical infrastructure.

From the current point of view I agree - with current transaction fees I would stay on mainchain, with Lightning as an option for smaller payments in hign-fee times.
Of course the point of this thread however is to find projects which have the potential to change that. For now, still Nomic, Stacks, perhaps BEVM and tBTC are the most interesting ones.
Drivechain is cool but I don't know if it will happen in the next 10 years on BTC. Perhaps if it's first tried on a "real" altcoin, not only on testnets.

I can find only few of them useful but I would never keep any large amounts of coins long term in any of bitcoin sidechains.
It's funny that some people are promoting Lightning Network so much but only 5,122 BTC is locked so far, that is nothing compared to 21 million.
I won't even get into less know sidechains that are making a bunch of false promises.
Instead of using sidechains, it would be much more interesting with drivechain.info.

but many side chains bridge to many mainnets
take liquid for instance.. it has many different tokens/assets/pegged coins. so its not solely a skin of bitcoin, it doesnt just cover bitcoin

i know you are trying to interpret the contracts(federations) within the sidechain which are pegged/linked to a particular mainnet justify the "layer" buzzword. but thats then assuming that a sidechain that operates with many networks is not the layer due to bridging to many networks, but within the sidechain its the contract(federation) that is the (?)layer(?) of a mainnet, thus making it appear that the mainnet must be then within the sidechain if the (?)"layer"(?) is within the sidechain.. it starts to not make sense in that way.

this is why the main community prefer the wordage of bridges. offramps, subnetworks rather than 'layers'(skins)
especially people are not going along with the "ontop"(better) subliminal's too when talking about subnetworks as most subnetworks are less secure then mainnets

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anyway a good stat to update regularly in the top post of topic is how much value in locked utxo's are pegged to a particular subnetwork bridge, as that then shows which ones are populating the most

I actually agree with you a bit about this issue, above all if we talk about sidechains. From a networking point of view, a sidechain is indeed a subnetwork, or in some cases a separate network with some overlap with the main network (if not all nodes on the "L2" chain are also nodes of the L1 chain).

But only a bit

Because if we look at the whole thing from a transaction-centric view, i.e. instead of looking at the node network graph, looking at the transaction graph, then I think the Layer-2 analogy still holds.

If an user pegs-in 1 BTC into a sidechain, and then 1 month later another users pegs-out this 1 BTC after with the "sidechainBTC" (i.e. the utxos created on the sidechain as a result of the peg-in) 1000 transactions were done on the sidechain, from Bitcoin's transaction graph's point of view what you do is bundling 1000 transactions into one (very simplified). The sidechainBTC transactions thus can be considered a layer to the "true BTC" of the mainchain.

Perhaps we can agree on that sidechains can act as a layer for transactions, but they aren't only a layer but actually can have a lot of other functions too, and from a networking point of view they are actually often not really a layer.

i appreciate d5000 taking the time to delve into the wider world of subnetworks so ill give him some merit


but the wordage of the whole L2/"layer" tag is becoming defunct/redundant

its not like most subnetworks remain layers that only wrap around a core network and function solely to secure the enclosed value of that one mainnet.. instead many are subnetworks that bridge between multiple mainnets so thats why the community prefer words like subnetworks and bridges (think subways and highways and bridges with on and off ramps between multiple communities)

the terminology of analogies is not fixed but the "layer" term is getting less and less relevance when most subnetworks start offering access to different currencies and no longer just wrap around and function with one network

as for the definition of subnetworks. is similar/akin to subdomains and also illustrating the analogy that these subnetworks are below the mainnet in terms of security. as many subnetworks will never be as secure as the mainnet, thus a subclass of network security, rather than the illusion/delusion of top quality penthouse, top security, leader, subliminal word garbage done for fame stealing and false promising of being 'solutions'/better than the mainnet