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‎account-contract/README.md‎

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@@ -97,60 +97,78 @@ Install TypeScript dependencies:
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yarn install
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```
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## Usage
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Start the local network:
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### 1. Deploy the Account Contract
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```bash
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aztec start --local-network
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```
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```typescript
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import { PasswordAccountContract } from "./ts/password-account-entrypoint";
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import { Fr } from "@aztec/foundation/fields";
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Deploy the account contract to the local network:
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// Create account contract with password
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const password = new Fr(123456789);
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const accountContract = new PasswordAccountContract(password);
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```bash
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npx tsx deploy-account-contract.ts
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```
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// Get artifact and initialization args
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const artifact = await accountContract.getContractArtifact();
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const { constructorName, constructorArgs } =
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await accountContract.getInitializationFunctionAndArgs();
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### Use the account contract as normal
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// Deploy using DeployMethod
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// See ts/deploy-account-contract.ts for full example
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```
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## Security Considerations
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### 2. Create Transactions
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- The password is hashed using Poseidon2 before storage
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- Password is required for every transaction (no caching)
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- Password is included in transaction data (encrypted in private state)
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- This is a demonstration contract - production use should consider additional security measures
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- Consider using signature-based accounts for most production use cases
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The account contract authenticates transactions by verifying the password hash:
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## Important Considerations
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```typescript
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// Transactions automatically include the password in the entrypoint call
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// The password is hashed with Poseidon2 and compared to stored hash
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```
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When implementing custom account contracts in Aztec, be aware of these critical points:
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### 3. Authorization Witnesses
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### All Execution Starts in Private
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For cross-contract calls requiring authorization:
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**This is the most important gotcha**: In Aztec, all transaction execution begins in the private context, even if your contract only has public functions. The account contract's `entrypoint` function always executes in private first.
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```typescript
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// The account can authorize actions for other contracts
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// Password is used to verify the authorization
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```
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- Your `entrypoint` function must be a `private` or `unconstrained private` function
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- Even when calling public functions on other contracts, the call originates from private execution
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- Authentication logic in the entrypoint runs in the private context
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- If you need to validate anything on-chain, you must enqueue public calls and handle them accordingly
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## Fee Payment Methods
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### Password/Secret Storage
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The contract supports three fee payment options:
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- **Never store passwords in plain text**: Always hash sensitive data before storage (like we do with Poseidon2)
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- The `hashed_password` is stored in `PublicImmutable` storage, meaning it's visible on-chain but cannot be changed
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- Consider whether your authentication secret should be changeable (would require mutable storage)
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1. **EXTERNAL (0)**: Another contract pays the fee
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2. **PREEXISTING_FEE_JUICE (1)**: Account pays with existing FeeJuice balance
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3. **FEE_JUICE_WITH_CLAIM (2)**: Account pays with FeeJuice claimed in same transaction
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### Entrypoint Function Signature
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## Security Considerations
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- The entrypoint must match the expected signature for account contracts
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- It receives the payload (functions to call) and fee payment options
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- The password is hashed using Poseidon2 before storage
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- Password is required for every transaction (no caching)
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- Password is included in transaction data (encrypted in private state)
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- This is a demonstration contract - production use should consider additional security measures
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- Consider using signature-based accounts for most production use cases
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### State Management
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- Private state is encrypted and only visible to those with the viewing key
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- Public state is visible to everyone on-chain
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- Choose storage types carefully: `PublicImmutable`, `PublicMutable`, `PrivateImmutable`, `PrivateMutable`, `PrivateSet`, etc.
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- Changing storage types after deployment requires a new contract deployment
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### Transaction Construction
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- Account contracts need TypeScript integration for proper transaction construction
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- You must implement the `AccountContract`, `AccountInterface`, and custom entrypoint classes
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- The entrypoint class handles encoding your authentication mechanism into the transaction payload
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- Mismatches between Noir and TypeScript implementations will cause authentication failures
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### Testing and Debugging
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- Private execution errors can be harder to debug since execution details aren't always visible
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- Test thoroughly with different fee payment methods
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- Ensure your authentication mechanism works for both direct calls and authwit flows
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### Gas and Fee Considerations
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- Account contracts are responsible for paying transaction fees
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- You must handle the fee payment method selection properly
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- Failed fee payments will cause the entire transaction to fail
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- Consider how users will fund their account contracts with Fee Asset
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## Dependencies
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‎account-contract/ts/deploy-account-contract.ts‎

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import { AztecAddress } from '@aztec/stdlib/aztec-address';
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import { SponsoredFeePaymentMethod } from '@aztec/aztec.js/fee';
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import { getContractInstanceFromInstantiationParams } from '@aztec/stdlib/contract';
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import { CardGameContract } from '@aztec/noir-contracts.js/CardGame';
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import { SponsoredFPCContractArtifact } from '@aztec/noir-contracts.js/SponsoredFPC';
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import { SPONSORED_FPC_SALT } from '@aztec/constants';
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import { Fr } from '@aztec/foundation/fields';
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await wallet.registerContract(await getSponsoredPFCContract(), SponsoredFPCContractArtifact);
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const hello = new DeployMethod(
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const accountContractDeployMethod = new DeployMethod(
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publicKeys,
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wallet,
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artifact,
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constructorName,
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)
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const { estimatedGas, stats } = await hello.simulate(deployAccountOpts);
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const { estimatedGas, stats } = await accountContractDeployMethod.simulate(deployAccountOpts);
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console.log(estimatedGas);
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console.log(stats);
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const deployedAccountContract = await accountContractDeployMethod.send(deployAccountOpts).wait();
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await wallet.createAccount({ secret: Fr.random(), contract: passwordAccountContract, salt: Fr.random() });
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const cardGameContract = await CardGameContract.deploy(wallet).send({ from: deployedAccountContract.contract.address }).deployed();
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console.log(cardGameContract)

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