milano

Experimenting with client side offline zk proofs.

The goal is to create a QR code that contains a self-contained zk proof of some transfer transaction from era mainnet.

Running

Generate the .json file with all the data using the python creator file:

python3 online_creator.py transaction 0xbe8d5c1eba50aec04e07d627fb2bfcf71cafd242c9e231681ffc5aba12cc385c tmp/output_file.json

(or for NFT):

Running (for NFT)

python3 online_creator.py nft 0x1f13941d0995e111675124af4b0f9bdcc70390c3 0xfac041bcf2c4b43319c2c0a39aba53f4cbe44fe5 tmp/output_file.json

Proving

This will result in the output_file.json file with necessary data.

Then you can verify it in sp1, by running (from the sp1 directory):

cargo run --release -- --input-file=../tmp/output_file.json --execute

This will check that the output_file.json file is correct.

Then you can generate the 'large' but fast proof (will take around 30 seconds):

cargo run --release -- --input-file=../tmp/output_file.json  --prove 

And then finally, the 'small' (KZG) proof (will take multiple minutes) - and this is what we need for the next step.

RUST_LOG=info cargo run --bin evm --release --  --input-file=../tmp/output_file.json --output-proof-file=../tmp/proof.json

Generating QR code with proof

Now you can generate the QR code that will contain your proof:

cargo run -- --input-file=../examples/proof_nft.json --output-file=../examples/proof_nft_qr.jpg

Verify (on raspberry pi)

Finally you can verify the proof from the QR code on your offline device:

python3 verifier.py qr ../examples/proof_nft_qr.jpg

In this case, you also have to 'hardcode' the verification key in the device code.

You can see the example in 'open_door.py' on how this can be used.

Stuff to do

• Verify that transaction has executed correctly (get the receipt too).
• The QR codes should also be 'signed' by the holder/sender.
• And verifier should check that signature.