Confidential Transfers SDK

The Confidential Transfers SDK is a TypeScript library that provides a set of functions to interact with the ERC20 Confidential Transfers extension.

Installation

1. Install the package:

npm install @noxlabs/confidential-transfers-sdk

2. Install the zk keys or generate them

KEYS_SOURCE_URL="https://tan-hollow-gerbil-264.mypinata.cloud/ipfs/bafybeib7myufblrjs6tsmv3pb5guunwk4byg43qoxj6d5bjtipx2aptlke"
curl -L "${KEYS_SOURCE_URL}/init/init_final.zkey" -o keys/init/init_final.zkey
curl -L "${KEYS_SOURCE_URL}/apply/apply_final.zkey" -o keys/apply/apply_final.zkey
curl -L "${KEYS_SOURCE_URL}/update/update_final.zkey" -o keys/update/update_final.zkey
curl -L "${KEYS_SOURCE_URL}/transfer/transfer_final.zkey" -o keys/transfer/transfer_final.zkey
curl -L "${KEYS_SOURCE_URL}/applyAndTransfer/applyAndTransfer_final.zkey" -o keys/applyAndTransfer/applyAndTransfer_final.zkey

How to use

1. Import the package:

import { SDK } from "@noxlabs/confidential-transfers-sdk"

2. Initialize the SDK:

const sdk = new SDK(contractAddress, provider, {
  paths: {
    helpers: "@noxlabs/confidential-transfers-sdk/artifacts/proofs-helpers",
    keys: "<path to downloaded zk keys>",
  },
})

3. Generate the confidential keys:

const { cPrivateKey, cPublicKey_X, cPublicKey_Y } =
  await SDK.deriveConfidentialKeys(entropy)

The entropy could be any string, but it's should be somehow derived from the user's private key or private key should be involved in the derivation. We recommend two options:

1. Use the user's master private key as the entropy: entropy = ethPrivateKey.
2. Use this derivation process: entropy = (random bytes > sign by user > signature)

4. Generate the proof:

const initInputs = await sdk.getCircuitInputsForInit(cPrivateKey)
const initProofOutput = await sdk.generateInitProof(initInputs)
const initParams = sdk.getInitParams(initProofOutput)
await sdk.token.cInit(initParams)