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https://github.com/zkemail/zk-regex
A library to do regex verification in circom, adapted from the original zk-email. It additionally generates lookup tables for halo2-regex.
https://github.com/zkemail/zk-regex
Last synced: 3 months ago
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A library to do regex verification in circom, adapted from the original zk-email. It additionally generates lookup tables for halo2-regex.
- Host: GitHub
- URL: https://github.com/zkemail/zk-regex
- Owner: zkemail
- License: gpl-3.0
- Created: 2023-01-13T08:22:30.000Z (over 1 year ago)
- Default Branch: main
- Last Pushed: 2024-03-24T17:36:15.000Z (3 months ago)
- Last Synced: 2024-03-24T23:36:21.314Z (3 months ago)
- Language: Circom
- Homepage:
- Size: 10.2 MB
- Stars: 51
- Watchers: 3
- Forks: 18
- Open Issues: 18
-
Metadata Files:
- Readme: README.md
- License: LICENSE
Lists
- awesome-circom - zkRegex
README
# zk-regex
A library to do regex verification in circom. It will also generate lookup tables compatible with [halo2-regex](https://github.com/zkemail/halo2-regex) soon.
## Introduction
This library provides circom circuits that enables you to prove that
- the input string satisfies regular expressions (regexes) specified in the chip.
- the substrings are correctly extracted from the input string according to substring definitions.
This is a JS/Rust adaptation of the Python regex-to-circom work done by [sampriti](https://github.com/sampritipanda/) and [yush_g](https://twitter.com/yush_g) at https://www.zkregex.com
In addition to the original work, this library also supports the following features:
- CLI to dynamically generate regex circuit based on regex argument
- Extended regex circuit template supporting:
- group and negation regexes.
- a decomposed regex definition, which is the easiest way to define your regex.
You can define a regex to be proved and its substring patterns to be revealed.
Specifically, there are two ways to define them:
1. (manual way) converting the regex into an equivalent determistic finite automaton (DFA), selecting state transitions for each substring pattern, and writing the transitions in a json file.
2. (automatic way) writing a decomposed version of the regex in a json file with specifying which part of the regex is revealed.
While the manual way supports more kinds of regexes than the automatic way, the latter is easier and sufficient for most regexes.
### Theory
To understand the theory behind the regex circuit compiler, please checkout [this blog post](https://katat.me/blog/ZK+Regex) (edits in progress). You can also look at the original regex description and how it ties into the original zk email work at the [original zk-email blog post regex overview](https://blog.aayushg.com/posts/zkemail#regex-deterministic-finite-automata-in-zk).
## How to use
### Install
Install yarn v1, or run `yarn set version classic` to set the version.
Also make sure that [`circom`](https://docs.circom.io/getting-started/installation/) is installed.
Clone the repo and install the dependencies:
```
yarn install
```
### Compiler CLI
`zk-regex` is a CLI to compile a user-defined regex to the corresponding regex circuit.
It provides two commands: `raw` and `decomposed`
#### `zk-regex decomposed -d -c -t -g `
This command generates a regex circom from a decomposed regex definition.
For example, if you want to verify the regex of `email was meant for @(a|b|c|d|e|f|g|h|i|j|k|l|m|n|o|p|q|r|s|t|u|v|w|x|y|z)+.` and reveal alphabets after @, you can define the decomposed regex as follows.
```
{
"parts":[
{
"is_public": false,
"regex_def": "email was meant for @"
},
{
"is_public": true,
"regex_def": "(a|b|c|d|e|f|g|h|i|j|k|l|m|n|o|p|q|r|s|t|u|v|w|x|y|z)+"
},
{
"is_public": false,
"regex_def": "."
}
]
}
```
Note that the `is_public` field in the second part is true since it is a substring to be revealed.
You can generate its regex circom as follows.
1. Make the above json file at `./simple_regex_decomposed.json`.
2. Run `zk-regex decomposed -d ./simple_regex_decomposed.json -c ./simple_regex.circom -t SimpleRegex -g true`. It outputs a circom file at `./simple_regex.circom` that has a `SimpleRegex` template.
#### `zk-regex raw -r -s -c -t -g `
This command generates a regex circom from a raw string of the regex definition and a json file that defines state transitions in DFA to be revealed.
For example, to verify the regex `1=(a|b) (2=(b|c)+ )+d` and reveal its alphabets,
1. Visualize DFA of the regex using [this website](https://mindfa.onrender.com/min_dfa).
2. Find state transitions matching with the substrings to be revealed. In this case, they are `2->3` for the alphabets after `1=`, `6->7` and `7->7` for those after `2=`, and `8->9` for `d`.
3. Make a json file at `./simple_regex_substrs.json` that defines the state transitions. For example,
```
{
"transitions": [
[
[
2,
3
]
],
[
[
6,
7
],
[
7,
7
]
],
[
[
8,
9
]
]
]
}
```
4. Run `zk-regex raw -r "1=(a|b) (2=(b|c)+ )+d" -s ./simple_regex_substrs.json -c ./simple_regex.circom -t SimpleRegex -g true`. It outputs a circom file at `./simple_regex.circom` that has a `SimpleRegex` template.
### Circuit Usage
The generated circuit has
- 1 template arguments:
- `msg_bytes`: the number of characters for the input string.
- 1 input signals:
- `msg[msg_bytes]`: the input message to match against
- 1 + (the number of substring patterns) output signals:
- `out`: a bit flag to identify whether the substring of the input string matches with the defined regex.
- `reveal(i)[msg_bytes]`: The masked version of `msg[msg_bytes]`. Each character in `msg[msg_bytes]` is turned to zero in `reveal(i)[msg_bytes]` if it does not belong to the i-th substring pattern.
For more examples in action, please checkout the test cases in the `./packages/circom/circuits/common` folder.
### Helper APIs
A package in `./packages/apis` provides nodejs/rust apis helpful to generate inputs of the regex circuits.
## Development
Welcome any questions, suggestions or PRs!
### Testing
```bash
yarn test
```