SHIELD

The shield is a development framework for circom developers, but we plan it for other languages such as CAIRO, SNARKYJS, etc.

The core reason is to provide libraries, plugins, and testing tools to ensure code quality and security.

Circomlib (which is the most popular library to build circom circuits) has over 1800 weekly downloads.

Pre-Requisite

You have to setup the environment before using it and install the following to get started with shield cli.

#### Windows

- rust
- circom
- nodejs

In future versions, we will provide a script to setup the environment with single command execution.

#### Linux/Mac

- nodejs

Installation

Install shield globally with npm:

``bash

$ npm i -g @xorddotcom/shield
`



Usage

$3

To create a sample project, run
In future versions, we will provide a script to setup the environment with single command execution.

`bash

$ shield init
`

create a JavaScript, TypeScript project, or an empty shield.config.js

`
? What do you want to do? …
❯ Create a JavaScript project
Create a TypeScript project
Create an empty shield.config.js
Quit
`

$3

`bash

$ shield compile
`

`bash

Usage: shield compile [options]

compiles the circuits to verifer contracts

Options:
-c, --circuit specific circuit to compile
-h, --help display help for command


`

$3

Set up your project with the following minimal shield.config.js at the root.

`javascript

module.exports = {
// (optional) solidity version for compiled contracts, defaults to ^0.8.0
solidity: "^0.8.0",
circom: {
// (optional) Base path for files being read, defaults to ./circuits/
inputBasePath: "./circuits/",
// (optional) Base path for files being output, defaults to ./circuits/
outputBasePath: "./build/",
// (required) The final ptau file, relative to inputBasePath, from a Phase 1 ceremony
ptau: "powersOfTau28_hez_final_10.ptau",
// (required) Each object in this array refers to a separate circuit
circuits: [
{
// (required) The name of the circuit
name: "demo",
// (optional) Protocol used to build circuits ("groth16" or "plonk"), defaults to "groth16"
protocol: "groth16",
// (optional) Input path for circuit file, inferred from name if unspecified
circuit: "demo.circom",
// (optional) Output path for zkey file, inferred from name if unspecified
zkey: "demo.zkey",
// (optional) Input path for input signal data, inferred from name if unspecified
input: "input.json",
// // (optional) Output path for witness file, inferred from name if unspecified
witness: "demo.json",
},
],
},
};

`


Your project structure should look like this:

`javascript

.
├── circuits
│ └── demo.circom
└── shield.config.js

`
Now, you can use shield compile to compile the circuits and output demo_Verifier.sol, demo.zkey,demo.wasm and Verifier contract interface files into their respective directories:

`javascript
.
├── build
│ └── demo
│ ├── circuit_0000.zkey
│ ├── demo_js
│ │ ├── demo.wasm
│ │ ├── generate_witness.js
│ │ └── witness_calculator.js
│ ├── demo.r1cs
│ ├── demo.sym
│ ├── demo.zkey
│ └── verification_key.json
├── circuits
│ ├── demo.circom
│ ├── input.json
│ ├── demo.wtns
│ ├── demo.json
│ └── powersOfTau28_hez_final_10.ptau
├── contracts
│ ├── demo_Verifier.sol
│ └── interfaces
│ └── IdemoVerifier.sol
└── shield.config.js


`

$3

Debug feature allows you to display the circom circuits logs, input/output signals logs, and the passed/failed Constraints along with signals calculations.

To debug with an error stack trace and generate a witness JSON/Wtns file, run:

`bash

$ shield debug
`


`bash

Usage: shield debug [options]

debug (display input/output signals, circuit logs, and passed/failed constraints ) and generate a witness file of the circuit

Options:
-c, --circuit specific circuit to debug
-h, --help display help for command

`

#### Example debug logs

`

Input Signals:

┌───────────┬────────┐
│ (Signals) │ Values │
├───────────┼────────┤
│ c │ '4' │
│ a │ '2' │
│ b │ '2' │
└───────────┴────────┘

No output signal found:

Constraint no 1: passed

=> ((-1)signal2) (1signal3) = ((-1)signal1)

=> ((-1)2) (12) = ((-1)4)

Related signals:

signal2: main.a, value: 2

signal3: main.b, value: 2

signal1: main.c, value: 4


`

Contribution


Ethereum : 0xf1f7dfb65C47445ACA50319512373A50C396fCdF

Optimism : 0xf1f7dfb65C47445ACA50319512373A50C396fCdF

Polygon : 0xf1f7dfb65C47445ACA50319512373A50C396fCdF

Zksync : 0xf1f7dfb65C47445ACA50319512373A50C396fCdF

Arbitrum : 0xf1f7dfb65C47445ACA50319512373A50C396fCdF`