There is a general consensus that sidechains and LN/sidechain type protocols are Layer 2 on top of the Bitcoin base layer, layer 1.
I would not say there is general consensus here e.g. https://twitter.com/gakonst/status/1146793685545304064
In the same way that L2 = new layer built on L1 that inherits full L1 security while moving tx execution off L1, I would apply more or less the same definition to L3. L3 = new layer built on L2 that inherits full L2 security while moving tx execution off L2.
Users can securely move coins from L1 to L2, from L2 to L3, back to L2, then back to L1, as the need arises.
Yeah, I agree, it's hard to argue that a crummy cosmos sidechain bound to Bitcoin with a kludgey solution to finality agreement does not really inherit the security. It sems to me like it would compound rather than sum, as in, the weakness of both would be the result rather than inheriting the strength of the "lower" layer.
Since there isn't a stronger blockchain than Bitcoin, side chains only reduce security, in direct proportion with their real decentralisation.
LN, by contrast, is a p2p protocol rather than a global broadcast protocol, and it rides the optimum path in terms of game theory and cryptographic security. Which is why I say, there is no other layer 2, to ape Saylor's "there is no second best". LN thus does not have weaknesses in the same way that Bitcoin has, thus it can be said it adds security rather than compounds its weaknesses.
Really, I think an immediate disqualifier for a protocol to be called layer 3 when it rides on top of LN (and maybe tickles the main chain a bit for such as bonds), is that the network is aiming to achieve a similar goal.
A side chain is just another shitcoin chain, and another LN network is going to lag the main LN swarm by anonymity set and liquidity.
Thus, a layer 3 could not be merely a payment network, and cannot either be a global broadcast based network, since it is supposedly using the strengths of the two best at this type of task. It would have to be a data storage/retrieval or routing protocol or some combination of these two.
I think a bearer certificate based securities exchange protocol could also qualify as L3 since it has a substantially different goal, it is not intended to be a money, but a way to distribute profits back to investors.
Off the cuff I can't think of how to make such a system work, or what kind of consensus it would use, but it seems to me like this might actually be a case where the Proof of Stake style model could work, based on the fact that the stake is not issued by any party in the network, which is the root of Proof of Stake as a L1 platform.
I'll try to keep my mind inside the box of thinking about an L3 that provides anonymity though. Someone else will eventually figure out the same thing if they don't read my comment or have the idea relayed to them from it.
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it's hard to argue that a crummy cosmos sidechain bound to Bitcoin with a kludgey solution to finality agreement does not really inherit the security.
If you are referring to Nomic and Babylon chains, they are using bitcoin to improve their own security (clearly so, solving the weak subjectivity problem) but not really "inheriting security" in the same way that an L2 does.
LN thus does not have weaknesses in the same way that Bitcoin has
What do you mean by this? LN does have a different security model than L1, introducing the dependency of the fault proof ("penalty tx") to prevent double-spending, making LN payments vulnerable to short-term miner censorship or L1 congestion.
I think an immediate disqualifier for a protocol to be called layer 3 when it rides on top of LN (and maybe tickles the main chain a bit for such as bonds), is that the network is aiming to achieve a similar goal.
Does LN not aim to achieve a similar goal as bitcoin L1 (p2p payments) only in a more scalable way? In any case, it seems arbitrary to me to say "this layer has the same use-case, so it's not really a new layer". imo the layer terminology should be applied independently of the use-case of the layer, and look moreso at the technical architecture and relationships to other protocols to determine whether it's really a higher layer or something else.
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Yes, sidechains benefit from bitcoin but that doesn't mean anything if a small group of the userbase has outsized control over token issuance.
Bitcoin's weakness relates to reorgs and its slow, broadcast propagation pattern. Lightning's weakness is griefers and expiring/stuck channels.
I don't think what bitcoin does is at all similar to LN. There is a much weaker consensus in LN, because it doesn't have to share the state changes, only the p2p information for generating paths and a summary at the end of each channel, the security problems for LN come from mischief with channel partners and channel liquidity.
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