smart-wallet-sdk

Browser-safe Rust/WASM SDK for Smart Wallet v2.

The SDK contains the client-side protocol helpers needed by applications that integrate Smart Wallet:

• API request and response data types.
• Gmail address canonicalization and email hash helpers.
• Google JWT parsing for the proof flow.
• Sigma proof generation for escrow claims.
• Opaque-byte 2-of-3 key-share split and combine helpers.

The SDK does not generate wallet keys, derive blockchain addresses, validate public keys, integrate with browser wallets, store custody data, submit transactions, query RPC providers, or send API requests.

Rust

let email = smart_wallet_sdk::email::canonicalize_email(" [email protected] ")?;
let shares = smart_wallet_sdk::key_share::split_secret(b"ordinary wallet secret")?;
let secret = smart_wallet_sdk::key_share::combine_shares(&shares[0], &shares[1])?;

WASM

Install the published browser package with:

npm install @zkfold/smart-wallet-sdk

Use the generated module from browser code:

import init, { canonicalize_email, prove_claim } from "@zkfold/smart-wallet-sdk";

await init();
const email = canonicalize_email(" [email protected] ");

Build the browser package with:

wasm-pack build --scope zkfold --target web --out-dir pkg --out-name smart_wallet_sdk --features wasm

The WASM facade exports JSON-oriented functions for browser callers:

• canonicalize_email(email)
• email_hash(email)
• key_share_email_hash(email)
• split_secret(secretBase64url)
• combine_secret_shares(firstShare, secondShare)
• parse_google_jwt(compactJwt)
• prove_claim(inputJson)
• prove_key_share(inputJson)

Browser Function Contracts

canonicalize_email(email) trims ASCII whitespace, lowercases ASCII characters, rejects unsupported characters, and returns the canonical Gmail address string.

email_hash(email) returns the 0x-prefixed Keccak-256 hash of the supplied email string. Call canonicalize_email first for user-entered send and balance inputs.

key_share_email_hash(email) canonicalizes the email and returns the 0x-prefixed SHA-256 hash used to key optional key-share storage.

parse_google_jwt(compactJwt) accepts a compact Google ID token and returns a JSON string with headerB64, payloadB64, kid, email, emailHash, and the public JWT offset data needed by the proof flow. The JWT signature remains local to the browser.

prove_claim(inputJson) accepts:

{
  "compactJwt": "header.payload.signature",
  "googleKey": {
    "kid": "google-key-id",
    "modulus": "0x...",
    "exponent": 65537
  },
  "chain": {
    "type": "evm",
    "chainId": 11155111,
    "escrow": "0x1111111111111111111111111111111111111111"
  },
  "refs": [
    "0xcccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccc"
  ],
  "to": "0x3333333333333333333333333333333333333333",
  "relayer": "0x2222222222222222222222222222222222222222"
}

For Cardano, use:

{
  "type": "cardano",
  "network": "preprod"
}

with Cardano refs in txHash#index form and Cardano to and relayer addresses. The function returns the JSON request body for /v1/claim.

prove_key_share(inputJson) accepts:

{
  "compactJwt": "header.payload.signature",
  "googleKey": {
    "kid": "google-key-id",
    "modulus": "0x...",
    "exponent": 65537
  },
  "operation": "store",
  "keyShareEmailHash": "0xaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa",
  "clientId": "partner-app",
  "challenge": "base64url-32-byte-challenge",
  "share": "serialized-share-for-store"
}

For retrieve proofs, set operation to retrieve and omit share. The function returns the proof object used by /v1/key-share or /v1/key-share/retrieve.