# Verifying On-Chain

# Verifying with the EVM ◊

To verify on-chain, generate a verifier smart contract after performing setup.

You can use the example from Commands, or create it by copying over a network and input file (assuming the ezkl repo is in your home directory):

cp ~/ezkl/examples/onnx/4l_relu_conv_fc/network.onnx ./
cp ~/ezkl/examples/onnx/4l_relu_conv_fc/input.json ./

then create the setup

ezkl gen-settings -M network.onnx
ezkl calibrate-settings -M network.onnx -D input.json --target resources
ezkl get-srs -S settings.json
ezkl compile-circuit -M network.onnx -S settings.json --compiled-circuit network.ezkl
ezkl setup -M network.ezkl --srs-path=kzg.srs

Now we use this setup to create an EVM verifier, which would be deployed on-chain.

Note: Due to the introduction of PUSH0 opcode in post-Shangai network, only contracts compiled with solc >= 0.8.20 end up using that opcode. If you want to deploy to a pre-Shangai network (which includes nearly all of the most popular L2s at the time of writing), you need to use solc 0.8.19 or earlier.

# gen evm verifier
ezkl create-evm-verifier --srs-path=kzg.srs --vk-path vk.key --sol-code-path verif.sol --settings-path=settings.json

ezkl gen-witness -D input.json -M network.ezkl
ezkl prove --witness witness.json -M network.ezkl --proof-path model.pf --pk-path pk.key --srs-path=kzg.srs

# install anvil if you haven't already
cargo install --git https://github.com/foundry-rs/foundry --profile local --locked anvil

# spin up a local EVM through anvil in a separate terminal 
anvil -p 3030

# deploy evm verifier
ezkl deploy-evm-verifier --addr-path=addr.txt --rpc-url=http://127.0.0.1:3030 --sol-code-path verif.sol 

# verify (EVM), make sure to copy the address stored in addr.txt and paste it into the addr param
ezkl verify-evm --proof-path model.pf --addr=$(cat addr.txt) --rpc-url=http://127.0.0.1:3030

Note that the .sol file above can be deployed and composed with other Solidity contracts, via a verify() function.

# Aggregation

Note: this is an advanced technique, very resource-intensive, and chances are you don't want to use this; if you are having trouble with proof size, first try asking about your problem in Telegram or Discord.

The above pipeline can also be run using proof aggregation to reduce the final proof size and the size and execution cost of the on-chain verifier. A sample pipeline for doing so would be as follows.

Grab a smaller model.

cp ~/ezkl/examples/onnx/1l_relu/network.onnx ./
cp ~/ezkl/examples/onnx/1l_relu/input.json ./

# Generate a new SRS. We use 20 since aggregation requires larger circuits (more commonly 23+).
ezkl get-srs --logrows 20 --srs-path=20.srs

# Create new circuit parameters
ezkl gen-settings -M network.onnx
ezkl calibrate-settings -M network.onnx -D input.json --target resources

Set up the first proof.

# Set up a new circuit
ezkl compile-circuit -M network.onnx -S settings.json --compiled-circuit network.ezkl
ezkl setup  -M network.ezkl --srs-path=20.srs --vk-path=vk.key --pk-path=pk.key 

# Single proof -> single proof we are going to feed into aggregation circuit. (Mock)-verifies + verifies natively as sanity check
ezkl gen-witness -D input.json -M network.ezkl
ezkl prove --proof-type=for-aggr -W witness.json -M network.ezkl --proof-path first.pf --srs-path=20.srs  --pk-path=pk.key

Setup the aggregate proof.

ezkl setup-aggregate --sample-snarks first.pf --srs-path 20.srs --logrows 20

# Aggregate -> generates aggregate proof
ezkl aggregate --logrows=20 --aggregation-snarks=first.pf --srs-path=20.srs --pk-path pk_aggr.key 

# Generate aggregate evm verifier
ezkl create-evm-verifier-aggr --sol-code-path verif.sol --srs-path=20.srs --vk-path vk_aggr.key --aggregation-settings=settings.json

# Spin up a local EVM through anvil 
anvil -p 3030

# deploy evm verifier
ezkl deploy-evm-verifier --addr-path=addr.txt --rpc-url=http://127.0.0.1:3030 --sol-code-path verif.sol 

# verify (EVM), make sure to copy the address stored in addr.txt and paste it into the addr param
ezkl verify-evm --proof-path proof_aggr.proof --addr=$(cat addr.txt) --rpc-url=http://127.0.0.1:3030

Also note that this may require a local solc installation. You can follow the SolidityLang instructions linked above, or you can use svm-rs to install solc. Here's how:

Install svm-rs:

cargo install svm-rs

Install a recent Solidity version (we use 0.8.20 in our implementation):

svm install 0.8.20

Verify your Solidity version:

solc --version