Main Challenges in Crypto Now, August 2024, develope a rollup blockchain is not difficult any more due to SDK of Arbitrum, zkSync. However, rollup is not perfect. See What is Rollup actually? (and validium rollup, sovereign rollups) for the arguing definition of rollups! According to Vitalik Buterin: Rollups batch transactions off-chain while posting data to Ethereum for security, providing scaling through compression. Validiums also enable off-chain transactions but use zero-knowledge proofs for validity without publishing transactions on-chain. The main difference between the two is data availability. In a rollup, the data is available on-chain, while in a validium, the data is stored off-chain and only a hash is stored on-chain. Also according to Vitalik: 51% attack can happen if an Ethereum's rollup uses external DA layer instead of storing data on Ethereum. As of August 2024, developing a rollup blockchain has become significantly easier thanks to...
