ZK Sync is a scaling and privacy engine for Ethereum. Its current functionality scope includes low gas transfers of ETH and ERC20 tokens in the Ethereum network. This document is a description of the JS library that can be used to interact with ZK Sync.
ZK Sync is built on ZK Rollup architecture. ZK Rollup is an L2 scaling solution in which all funds are held by a smart contract on the mainchain, while computation and storage are performed off-chain. For every Rollup block, a state transition zero-knowledge proof (SNARK) is generated and verified by the mainchain contract. This SNARK includes the proof of the validity of every single transaction in the Rollup block. Additionally, the public data update for every block is published over the mainchain network in the cheap calldata.
This architecture provides the following guarantees:
- The Rollup validator(s) can never corrupt the state or steal funds (unlike Sidechains).
- Users can always retrieve the funds from the Rollup even if validator(s) stop cooperating because the data is available (unlike Plasma).
- Thanks to validity proofs, neither users nor a single other trusted party needs to be online to monitor Rollup blocks in order to prevent fraud.
In other words, ZK Rollup strictly inherits the security guarantees of the underlying L1.
To learn how to use ZK Sync, please refer to the ZK Sync SDK documentation.
The legacy name franklin
is still used in many places of the code.
Prepare dev environment prerequisites: see docs/setup-dev.md
Setup:
franklin dev-up
franklin init
To completely reset the dev environment:
- Stop services:
franklin dev-down
- Remove containers data:
ssh minikube
rm -r /data/*
- Repeat the setup procedure above
franklin redeploy
Env config files are held in etc/env/
List configurations:
franklin env
Switch between configurations:
franklin env <ENV_NAME>
Seed for Metamask: fine music test violin matrix prize squirrel panther purchase material script deal
Geth: geth attach $(bin/kube-geth-url)
NOTE: if you are resetting geth, each Metamask account must be manually reset via Settings > Advanced > Reset account.
Run server:
franklin server
By default block chunk size set to 100
. For testing & development purposes you
ca change it to smaller values. Two places requires a change:
- Environment variable value in
./etc/env/dev.env
BLOCK_SIZE_CHUNKS
- Rust constant at
./core/models/params.rs
BLOCK_SIZE_CHUNKS
If you apply changes, do not forget to redeploy contractsfranklin redeploy
.
You must prepare keys. This only needs to be done once:
./bin/gen-keys
franklin redeploy
Run prover:
franklin prover
Run client
franklin client
Client UI will be available at http://localhost:8080.
Make sure you have environment variables set right, you can check it by running:
franklin env
. You should see * dev
in output.
-
Prerequisite:
franklin dev-up; franklin init
-
Start:
franklin start
-
Watch logs: Server:
franklin log-server
Prover:franklin log-prover
-
Stop:
franklin stop
franklin dockerhub-push
cd core/storage
- Add diesel migration
- Rename
core/storage/schema.rs.generated
toschema.rs
- Run tests:
franklin db-tests
To generate a proving key, from server
dir run:
cargo run --release --bin read_write_keys
It will generate a *VerificationKey.sol
and *_pk.key
files for 'deposit', 'exit' and 'transfer' circuits in the root folder.
Move files to proper locations:
mv -f n*VerificationKey.sol ./contracts/contracts/
mv -f *_pk.key ./prover/keys/
If the pregenerated leaf format changes, replace the EMPTY_TREE_ROOT
constant in contracts/contracts/PlasmaStorage.sol
.
cd contracts; yarn build
IMPORTANT! Generated .abi
and .bin
files are fed to cargo to build module plasma::eth
.
So you need to rebuild the code on every change (to be automated).
franklin publish-source