@klaytn/zkauth-sdk
v0.1.0
Published
SDK for zkAuth wallet
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Account Abstraction SDK for zkAuth Wallet
1. Introduction
This is a SDK for zkAuth wallet. It allows applications to interact with zkAuth smart contracts, which can create & manage AA wallet based on zkAuth protocol.
2. Installation
npm i @klaytn/zkauth-sdk
3. Usage
Some input/output values need to be stored in the DB or on the user side (localStorage, Cloud backup). The storage format doesn't matter, as long as it's structured in a way that makes it easy to retrieve user data.
Create a new AA wallet
Users can create their zkAuth wallet based on their OAuth2 idToken.
Prepare a JWT token from the OIDC provider for the initial owner (Note: Nonce isn't important)
Create and Save Wallet
- Input
ownerKey
: Generated private key of the initial ownersub
: JWT token'ssub
field after OAuth2 logininitialGuardian
: Initial guardian address based on the OAuth2 providerchainId
: Chain ID
- Output
cfAddress
: Calculated AA wallet addresssalt
: Salt to generate subHash. Note that the saltSeed issub
itself
- Save
ownerKey
: Save to user side (can't be saved to DB since it's non-custodial wallet)cfAddress
: Save to DB or user sidesaltSeed
: Save to DB or user sidesub (= saltSeed)
: Optionally save to DB or user side to reuse it in the future without re-login (e.g. to remove guardian)
const signer = new ethers.Wallet(ownerKey, JsonRpcProvider); const salt = await calcSalt(sub); const subHash = calcSubHash(sub, salt); const params: InitCodeParams & BaseApiParams = { initialGuardianAddress: initialGuardian, initialOwnerAddress: signer.address, chainIdOrZero: 0, subHash: subHash, provider: JsonRpcProvider, entryPointAddress: Addresses[chainId].EntryPointAddr, }; const scw = new RecoveryAccountAPI(signer, params, Addresses[chainId].RecoveryFactoryAddr); const cfAddress = await scw.getAccountAddress(); // Save wallet as your own
This stage makes
phantom
account, which means it's not been actually deployed on the chain. It will be deployed when user sends its first userOp transaction with the wallet. But we strongly recommend to deploy the account right after creating it since it won't be recoverable if user loses its private key before deploying it.- Input
Deploy Wallet (Strongly recommended)
The AA wallet can be deployed by i)
Factory.createAccount
or ii) FirstUserOp
withinitCode
in the transaction data. Since the owner address needs to be funded with KLAY for first method, it's recommended to use second method, which is more user-friendly.const signer = new ethers.Wallet(ownerKey, JsonRpcProvider); const scw = new RecoveryAccountAPI(signer, params, Addresses.RecoveryFactoryAddr); const target = cfAddress; // You can use any UserOp, so use entryPoint() as an example const data = ethers.utils.keccak256(Buffer.from("entryPoint()")).slice(0, 10); const tx: TransactionDetailsForUserOp = { target: target, data: data, value: 0, }; // With UserOp, the account will be deployed const uorc = await createAndSendUserOp(scw, bundlerUrl, chainId, tx);
Send a UserOp transaction
Users can send transaction called UserOp
with their zkAuth wallet. It requires ownerKey
to sign the transaction. If the wallet is phantom
wallet, UserOp
will contain the deployment process by initCode
.
Prepare a RecoveryAccountAPI with appropriate signer and parameters
// Assume that the wallet is already created and deployed // If it hasn't been deployed yet, you need to fill `InitCodeParams` and `BaseApiParams` with the appropriate values param = { scaAddr: cfAddress, provider: getProvider(network.chainId), entryPointAddress: Addresses.entryPointAddr, }; const scw = new RecoveryAccountAPI(signer, param, Addresses.RecoveryFactoryAddr);
Prepare transaction data
const tx: TransactionDetailsForUserOp = { target: targetAddress, data: txData, value: value, };
Send the userOp
const uorc = await createAndSendUserOp(scw, bundlerUrl, chainId, tx);
Add a new Guardian
Users can add a new guardian to their zkAuth wallet. It allows same provider but different account to be a guardian. (e.g., different Google account)
Prepare a JWT token from the target OIDC provider for the new Guardian (Note: Nonce isn't important)
Add the new Guardian
- Input
newSub
: JWT token'ssub
field taken from the previous stepnewSalt
: Salt to generate subHash. The saltSeed isnewSub
newGuardian
: New guardian address based on the providernewThreshold
: New threshold after adding the guardian
- Save
newSaltSeed
: Save to DB or user sidenewSub
: Optionally save to DB or user side to reuse it in the future without re-login (e.g. to remove guardian)
const newSalt = await calcSalt(newSub); const newSubHash = ethers.utils.keccak256(Buffer.from(newSalt + newSub)); const signer = new ethers.Wallet(ownerKey, JsonRpcProvider); const param: RecoveryAccountApiParams = { scaAddr: cfAddress, provider: JsonRpcProvider, entryPointAddress: Addresses[chainId].EntryPointAddr, }; const scw = new RecoveryAccountAPI(signer, param, Addresses[chainId].RecoveryFactoryAddr); const data = scw.encodeAddGuardian(newGuardian, newSubHash, newThreshold); const tx: TransactionDetailsForUserOp = { target: cfAddress, data: data, value: 0, }; const uorc = await createAndSendUserOp(scw, bundlerUrl, chainId, tx); ...
- Input
Remove a Guardian
Users can remove a guardian from their zkAuth wallet.
Prepare
sub
andguardian
to remove- If
sub
isn't stored in DB or user side, you need to get user's JWT token.
- If
Remove the Guardian
- Input
targetSub
: JWT token'ssub
field taken from the previous steptargetGuardian
: Guardian address to removenewThreshold
: New threshold after removing the guardian
- Delete
- Delete saved guardian's
sub
andsaltSeed
from DB or user side
- Delete saved guardian's
const newSalt = await calcSalt(targetSub); const newSubHash = ethers.utils.keccak256(Buffer.from(newSalt + targetSub)); const signer = new ethers.Wallet(ownerKey, JsonRpcProvider); const param: RecoveryAccountApiParams = { scaAddr: cfAddress, provider: JsonRpcProvider, entryPointAddress: Addresses[chainId].EntryPointAddr, }; const scw = new RecoveryAccountAPI(signer, param, Addresses[chainId].RecoveryFactoryAddr); const data = scw.encodeRemoveGuardian(targetGuardian, newSubHash, newThreshold); const tx: TransactionDetailsForUserOp = { target: cfAddress, data: data, value: 0, }; const uorc = await createAndSendUserOp(scw, bundlerUrl, chainId, tx); ...
- Input
Recover an AA wallet
If user wallet is ghost
wallet, user can't recover it, so delete it and create a new one.
Prepare user's recovery JWT tokens above a
threshold
based on registered guardians- Input
newOwnerAddress
: New owner's addressguardians
: Guardian addressescfAddress
: AA wallet addresschainId
: Chain ID
const args: typeDataArgs = { verifyingContract: guardian, sca: cfAddress, newOwner: newOwnerAddress, name: aud, chainId: chainId, }; const nonce = calcNonce(args); // get JWT token from server with nonce
- Input
Recover it
- Input
recoverTokens
: JWT tokens of registered guardians taken from the previous steprawRecoverTokens
: Base64 encoded JWT tokens of recoverTokens (include header, payload, and signature)newOwnerKey
: New owner's private key (private key ofnewOwnerAddress
)
- Save
newOwnerKey
: Save to user side (can't be saved to DB since it's non-custodial wallet)
- Delete
- Delete previous owner's private key from user side
const iss: string[] = []; const sub: string[] = []; const salts: string[] = []; const jwks: RsaJsonWebKey[] = []; const proofAndPubSigs: any[] = []; // recoverTokens are JWT tokens of registered guardians for (const recoverToken of recoverTokens) { const { iss: issTemp, sub: subTemp } = JSON.parse(recoverToken); const rawRecoverToken = rawRecoverTokens[idx]; const header = jwtDecode(rawRecoverToken, { header: true }); iss.push(issTemp); sub.push(subTemp); salts.push(await calcSalt(subTemp)); const provider = getProviderNameFromIss(issTemp); jwks.push((await getJWKs(provider, header.kid)) as RsaJsonWebKey); // Prepare zk proof const processedInput = ZkauthJwtV02.process_input(rawRecoverToken, jwks[idx].n, salts[idx]); const params = { circuit: "zkauth_jwt_v02", input: processedInput, }; // getProofAndPubSig function requests zk proof to the zkp server with the given input proofAndPubSigs.push(await getProofAndPubSig(params)); } const signer = new ethers.Wallet(newOwnerKey, JsonRpcProvider); const params: RecoveryAccountApiParams = { scaAddr: cfAddress, provider: JsonRpcProvider, entryPointAddress: Addresses[chainId].EntryPointAddr, }; const scw = new RecoveryAccountAPI(signer, params, Addresses[chainId].RecoveryFactoryAddr); for (const [idx] of recoverTokens.entries()) { const proof = proofAndPubSigs[idx].proof; const auth: AuthData = { subHash: calcSubHash(sub[idx], salts[idx]), guardian: guardians[idx], proof: generateProof(jwks[idx].kid, proof.pi_a, proof.pi_b, proof.pi_c, proofAndPubSigs[idx].pubSignals), }; // Note that subSigner is an optional signer which is owned by the service provider // The subSigner sends transaction on behalf of the user to improve user experience // Without subSigner, user needs to fund KLAY to the new owner address await scw.requestRecover(newOwnerAddress, auth, subSigner); } ...
Or directly use private key of current owner if user knows it.
- Input