# zkSync Era System Contracts audit contest Code4rena · zk-rollup system contracts · 10th March 2023 · #10 A public audit contest on Code4rena (zk-rollup system contracts), completed on 10th March 2023. 0xSimao placed #10. 1 of his findings is published: 1 medium. ## What zkSync Era System Contracts is zkSync Era is a zk-rollup that proves whole blocks as a single program: rather than executing transactions one by one, its bootloader runs the entire block as one big transaction that takes the array of transactions plus block metadata, the closest analogy being ERC-4337's EntryPoint, whose account-abstraction flow it also facilitates. ## Scope The zkSync Era system contracts and the bootloader: the privileged L2 contracts (deployer, nonce holder, L1 messenger and kin) and the Yul program that executes each block. ## Medium severity findings - [Time-sensitive contracts deployed on zkSync](https://0xsimao.com/findings/zksync-era-system-contracts-sensitive-contracts-deployed-sync) ## The contest [View the contest page](https://code4rena.com/audits/2023-03-zksync-era-system-contracts-contest)