Submit a Space and Time Proof of SQL proof

In this tutorial you are going to use the sxt-proof-of-sql library developed by Space and Time Labs to generate a zk-proof of the simple SQL query

SELECT a, b, c, d, e, f, g, h FROM table WHERE a = 2

on the following table

a	b	c	d	e	f	g	h
1	hello	foo	dc	hide	yin	chip	vim
2	bye	bar	marvel	seek	yang	dale	emacs

whose result is the table

a	b	c	d	e	f	g	h
2	bye	bar	marvel	seek	yang	dale	emacs

Then you will send the proof to zkVerify for on-chain verification.

Requirements

In order to follow this tutorial, you should have:

• A copy of the Horizenlabs/proof-of-sql-verifier repository:

  • if you have git installed on your system, you can just issue the command

  git clone https://github.com/HorizenLabs/proof-of-sql-verifier.git
  • otherwise, you can download a zipped version of the repository, and uncompress it

• A recent version of the rust toolchain (version >=1.81.0). See the official instructions for instructions on how to install

Generating the proving artifacts

In order to generate the zk-proof, go into the proof-of-sql-verifier directory

cd proof-of-sql-verifier

and run the command

cargo run --bin generate-sample-proof --features="rand test clap" -- --max-nu=4

This command can take a while to run, especially the first time, since it must compile the project from scratch. At the end it should generate three files: VALID_PROOF_MAX_NU_4.bin, VALID_VK_MAX_NU_4.bin, and VALID_PUBS_MAX_NU_4.bin.

If you happen to know a bit of Rust and SQL, you can take a look into src/bin/generate-sample-proof.rs source code and try modifying the table and query. If your table has more than 2^(4*2) = 256 rows, you may need to increase the value of the max-nu parameter accordingly. At the moment, we support a value of max-nu up to 8, corresponding to 2^(8*2) = 65536, and tables with up to 8 columns.

Submitting the proof to zkVerify via polkadot.js.org frontend

1. Head to polkadot.js.org frontend
2. Select your account (you must have some ACME).
3. Choose the settlementProofOfSqlPallet, and the submitProof extrinsic.
4. Inside the field vkOrHash select Vk
5. Fill in all the required fields by toggling the file upload switch, and uploading the vk, proof, and pubs files generated in the previous section.
6. Click on the submitTransaction button.