# Albus Dompeldorius CDAP - Dev Update #5 This is the fifth update for my work in the [CDAP](https://github.com/ethereum-cdap/cohort-zero/blob/main/development-updates.md#albus). ## What I have done since last update Since my [last update](https://hackmd.io/@albus/rJAnxRlVF), I have been working on my [zk-rollup concept](https://hackmd.io/-Uj7YPjYTkmIhuG7-FVmNQ), which allows for greatly reduced calldata usage while still preserving the same security of zk-rollups. The document is now expanded with more details about deposits, withdrawals, calldata estimates and examples. Anyone familiar with how zk-rollups work should now hopefully be able to grasp the main idea in my proposal. The reason I haven't posted to ethresear.ch yet, is that I want to implement an optimization first. (see below) ## What I will do next I am currently working on an optimization which would allow even less calldata usage. The current proposal uses 8 bytes of calldata for a batch of up to 65536 transfers from the same sender, but with the extra optimization this will be reduced to 6 bytes for a batch of an unlimited amount of transfers from the same sender. Once this is done, I will post the proposal on ethresear.ch to get some feedback on the proposal. I will reach out to zk-people to try to collaborate on an implementation. I am also working on how to generalize the concept to support smart contracts, and not just transfers. It seems that it can be done, but would require more calldata usage (but still less than for existing zk-rollups). As a test, I will try to work through how this can be adapted to a Uniswap contract, and compute what the calldata would be.