ct.js

const snarkjs = require("snarkjs");
const fs = require("fs");

// Example circuit for verifying a simple confidential transaction
const circuitDef = `
template ConfidentialTransaction() {
    signal input v;   // Transaction amount
    signal input r;   // Blinding factor
    signal input C;   // Commitment
    signal output valid;

    // Pedersen commitment check
    C === v * H + r * G;

    // Range proof (simplified for illustration)
    valid <== (v >= 0) && (v < MAX_VALUE);
}

component main = ConfidentialTransaction();
`;

async function main() {
    // Compile the circuit
    const { r1cs, wasm } = await snarkjs.compile(circuitDef);

    // Example inputs
    const inputs = {
        v: 5,
        r: 3,
        C: 5 * H + 3 * G  // Example commitment
    };

    // Generate the witness
    const witness = await snarkjs.wtns.calculate(r1cs, inputs, wasm);

    // Setup phase (trusted setup)
    const { zkey } = await snarkjs.groth16.setup(r1cs);

    // Generate proof
    const { proof, publicSignals } = await snarkjs.groth16.prove(zkey, witness);

    // Verification key
    const vkey = await snarkjs.zKey.exportVerificationKey(zkey);

    // Verify proof
    const isValid = await snarkjs.groth16.verify(vkey, publicSignals, proof);
    console.log("Proof is valid:", isValid);
}

main().catch(console.error);