Layer Cake whitepaper: Zero-Collateral L1 Bridges

[Seoulite]

I had no idea this had come out, but I don't follow the technicals all that strongly. I'm going to read it now and see what I can understand. Is that what Flare have been working on?

https://drive.google.com/file/d/10N6qs0qAF8DHGuNopTzsDOUghTc_m8fg/view

 

[Seoulite]

"In this paper, we propose a solution to the anti-network effect problem of cross-L1 bridges using
a novel state relay mechanism called the state connector, which delivers information from connected
blockchains without degrading their full security properties. The state connector can directly validate
state correctness without any need for data availability sampling or challenge periods, and it can
also implicitly withstand safety and liveness attacks on connected L1s. A resulting cross-L1 bridge
construction called LayerCake, which leverages the state connector, requires only a temporary collateral
lock-up while crossing the bridge that is proportional to the amount of value being sent across the
bridge. LayerCake makes no assumption about requiring slashing of validators on connected L1s in its
security model, and so the system has a zero long-term collateral requirement once value has crossed
the bridge. Compare this to other designs that are constrained by requiring the total value deposited
on their bridge across all users to be below 33% of the staking value on the less-valuable connected L1.
If the total value deposited surpasses this threshold, then it becomes favorable to attack such designs."

[Seoulite]

[Seoulite]

[Seoulite]

[Seoulite]

OK having read it, it seems to me that they have taken the F-asset idea of minting the same value on another chain, and have applied this to any chain. 

So if you want to move 1ETH to Solana you deposit on ETH, and pay a little fee and get 1sETH minted for you on Solana if everything is kosher. The collateral and moving service is done by the Bandwidth Provider. Their collateral is locked on ETH and Flare. The collateral is unlocked quickly on ETH and much slower on Flare. When it's all done the Bandwidth Provider gets the fee.

I guess I'm not 100% clear as to why the collateral needs to be locked on Flare as well. I guess it probably has something to do with utilising the State Connector contracts, and something to do with FLR being used as part of the collateral. Obviously the Flare team want to use Flare, but it's not obvious to me why FLR needs to be used. Maybe I'm missing some obvious technical thing. I'm not complaining about it, just don't understand it. 

So I guess this means that the F-asset system will still continue because it provides smart contract capabilities to non-smart chains. But this LayerCake thing seems to be an upgrade on the State Connector concept. Originally I think the state connector was for safety, and also could be used in some applications if they needed to check the state of another chain. But now they have expanded its role to being a bridge and checking collateral. 

[Seoulite]

from there FF discord:
 

Layman Cake

Imagine a bunch of islands (L1 Networks), each having their own individual colour of taxi (token) to roam around their island, but no way to travel between the islands.

LayerCake is like a footbridge between them but you cannot bring your taxi across. Instead, you park your taxi at one side of the bridge, pay a fee to walk across the footbridge and jump into a different coloured taxi on the other side. But to cross this footbridge, there needs to be a taxi waiting for you on the other side of the footbridge.

The fee you pay to walk across the footbridge is paid to the taxi providers (bandwidth (collateral) providers) who must operate sufficient taxis on both sides of the footbridge to facilitate the foot-traffic of the bridge. The sum of all taxis represents the rate at which pedestrians can cross the bridge.

The State Connector is like the border control which monitors the individual islands traffic and if taxis are correctly parked before crossing a footbridge.

 

 

[Seoulite]

I’ve been looking at the songbird explorer to see if I can see any differences. I am guessing part of the price movement is linked to a successful upgrade of the state connector. There seem to be a larger number of transactions per block, a great deal of: “submit price hash” and a new one I’ve seen “swap exact token for exact token”. I am guessing these might be connected.

edit: I guess price submissions are FTSO but there seem to be more than before. Anyway whatever I’m just bored. Next week there will be a roadmap apparently.

Edited March 28, 2022 by Seoulite

[Seoulite]

 

[Seoulite]

19 hours ago, Seoulite said:

I’ve been looking at the songbird explorer to see if I can see any differences. I am guessing part of the price movement is linked to a successful upgrade of the state connector. There seem to be a larger number of transactions per block, a great deal of: “submit price hash” and a new one I’ve seen “swap exact token for exact token”. I am guessing these might be connected.

edit: I guess price submissions are FTSO but there seem to be more than before. Anyway whatever I’m just bored. Next week there will be a roadmap apparently.

Ok we have some new kinds of transactions using the state connector contract: request attestations, whatever that means

[Seoulite]

1 hour ago, Seoulite said:

Ok we have some new kinds of transactions using the state connector contract: request attestations, whatever that means

These transactions are continuous every few seconds. I am guessing this is simply a generic term for asking the state connector to confirm something (attest is a fancy word for give information or prove something). So the SC proves the collateral is there on chain X and you are good to go with the bridge. They are calling this a revolutionary step forward in crypto tech. Let’s hope so.