@ -173,9 +173,9 @@ In February 2022, in the wake of the government of Russia's invasion of Ukraine,
At the time, zkSync only had a single block producer operated by zkSync's development company Matter Labs, and Matter Labs was only publishing blocks once every few hours. So about five hours after Wall submitted his withdrawal transaction on the zkSync rollup, the withdrawal was confirmed on Ethereum L1 and he received the TBTC in his L1 address. Wall then swapped the TBTC for ETH and donated the ETH to the Ukrainian government.[^63]
Now let's compare the #tBTCzkSyncTorch experience with the social media game that the #tBTCzkSyncTorch was based off of, the #LNTrustChain. The #LNTrustChain game worked similarly: the pseudonymous Hodlonaut started with 0.001 BTC on the bitcoin Lightning Network, then passed the torch on to someone else, who added a small amount of BTC then passed the torch on to someone else, and on and on in a long "trust chain".[^64] The trust chain got its name because each recipient of the torch was trusted to not just keep the sats for themselves but to add more sats and pass them along to someone else they trusted to do the same.
Now let's compare the #tBTCzkSyncTorch experience with the social media game that the #tBTCzkSyncTorch was based off of, the #LNTrustChain. The #LNTrustChain game worked similarly: the pseudonymous Hodlonaut started with 0.001 BTC on the bitcoin Lightning Network, then passed the torch on to someone else, who added a small amount of BTC then passed the torch on to someone else, and on and on in a long "trust chain".[^64] The trust chain got its name because each recipient of the torch was trusted to not just keep the BTC for themselves but to add more BTC and pass it along to someone else they trusted to do the same.
Because Lightning Network is a payment channel network, users in the #LNTrustChain had to establish channels between each other or be connected along a path of channels with the correct balances of outbound and inbound liquidity so they could send and receive the torch. There were more than a few cases where this liquidity requirement caused problems for would-be recipients of the torch.[^65]
Because Lightning Network is a payment channel network, users in the #LNTrustChain had to establish channels between each other or be connected along a path of channels with sufficient balances of outbound and inbound liquidity so they could send and receive the torch. There were more than a few cases where this liquidity requirement caused problems for would-be recipients of the torch.[^65]
#### Figure 3. #LNTrustChain participants seeking inbound liquidity to ensure the torch can be passed.
@ -183,9 +183,9 @@ Because Lightning Network is a payment channel network, users in the #LNTrustCha
> Image source: [^65]
In contrast, #tBTCzkSyncTorch participants never ran into any liquidity issues. By design, such liquidity issues could not have occurred. Rollups function like a blockchain, where users can send payments worth up to the full balance of their wallet with no concern for routing liquidity, and users can receive payments with no inbound capacity limit. There is no need to lock up capital or manage inbound/outbound liquidity to send and receive payments on a rollup, as is required in payment channel networks such as Lightning. These features make validity rollups more capital efficient and, at least for the new user, more user-friendly than Lightning.
In contrast, #tBTCzkSyncTorch participants never ran into any liquidity issues. By design, such liquidity issues could not have occurred. Rollups function like a blockchain, where users can send payments worth up to the full balance of their wallet with no concern for routing liquidity, and users can receive payments with no inbound capacity limit. There is no need to lock up capital in channels or manage inbound/outbound liquidity to send and receive payments on a rollup, as is required in payment channel networks such as Lightning. These features make validity rollups more capital efficient and, at least for new users, more user-friendly than Lightning.
It should be noted that this is an apples-to-oranges comparison: zkSync is a rollup that uses a blockchain data structure with global state, and Lightning is a payment channel network with peer-to-peer local state. These protocols are superficially similar in that they are both considered L2 protocols and both facilitate payments. Beyond that, they have important fundamental differences "under the hood". As such, this comparison of the two is not to say that Lightning doesn't have its own benefits compared to validity rollups, such as extremely low cost, highly secure, high-speed offchain transactions. But the challenges in getting Lightning to a usable state for p2p payments, as demonstrated by the #LNTrustChain user experience, reveal the tradeoffs and rough edges inherent to its design, which rollups avoid due to their own fundamental qualities.
It should be noted that this is an apples-to-oranges comparison: zkSync is a rollup that uses a blockchain data structure with global state, and Lightning is a payment channel network with peer-to-peer local state. These protocols are superficially similar in that they are both considered L2 protocols and both facilitate payments. Beyond that, they have important fundamental differences "under the hood". As such, this comparison of the two is not to say that Lightning doesn't have its own benefits compared to validity rollups, such as extremely low cost, highly secure, high-speed/high-throughput offchain transactions. But the challenges in getting Lightning to a usable state for p2p payments, as demonstrated by the #LNTrustChain user experience, reveal the tradeoffs and rough edges inherent to its design, which rollups avoid due to their blockchain-based design.
A more thorough look at the Lightning Network and how it compares, contrasts, and is complementary to validity rollups (and vice versa) can be found in [Section 4.4](#section-44-scaling-the-lightning-network-with-validity-rollups).
John Light
2 years ago
GitHub