# Account Abstraction Deployment Report

**Environment:** BlockDAG  Network\
**Version:** EntryPoint v0.6, Bundler Service, Verifying Paymaster

###  1. Introduction

We have successfully deployed Account Abstraction (AA) components on the BlockDAG test network in line with ERC-4337 specifications.

This deployment includes:

* EntryPoint v0.6 Contract – the central router for UserOperations.
* Bundler Service – a spec-compliant service for UserOperation validation, mempooling, and bundling.
* Verifying Paymaster Contract – an on-chain paymaster enabling sponsored (gasless) transactions with signature validation.

Together, these provide a secure and user-friendly foundation for gas abstraction and next-generation dApps.

### 2. Components Deployed

#### 2.1 EntryPoint v0.6

* Core contract validating and executing UserOperations.
* Provides replay protection, batching, and signature verification.
* Fully aligned with ERC-4337.

#### 2.2 Bundler Service

The bundler was deployed using the Eth Infinitism reference implementation and extended for our BlockDAG environment.

Key Features:

* Spec RPC Endpoints: eth\_sendUserOperation, eth\_estimateUserOperationGas, eth\_getUserOperationReceipt, eth\_getUserOperationByHash.
* Validation Pipeline: Uses simulateValidation to ensure correctness before acceptance.
* Mempool & Reputation: Valid UserOps are queued, invalid ones filtered with reputation checks.
* Execution Flow: Validate → Prefund/Paymaster check → Mempool → Bundle → Submit → Event tracking.
* Diagnostics: Detailed logging for signatures, prefund, gas fields, and execution results.

#### 2.3 Verifying Paymaster Contract

The Verifying Paymaster allows transactions to be sponsored by an on-chain contract, removing the need for users to hold native gas tokens.

**How It Works**

* The paymasterAndData field is built as:<br>

paymaster(20 bytes)&#x20;

\+ abi.encode(uint48 validUntil, uint48 validAfter)&#x20;

\+ signature

* Implementation in VerifyingPaymasterAPI.ts:
* Ensures the local verifying signer matches the on-chain verifyingSigner.
* Computes preVerificationGas with a placeholder 65-byte signature.
* Signs getHash(op, validUntil, validAfter).
* If PVG changes, re-computes and re-signs.<br>

**Runner Usage**

The runner (runop.ts) provides flexible integration:

* \--paymaster \<address> – specify Paymaster contract.
* \--verifierMnemonic \<file> – load verifying signer.
* \--pmValidFor \<seconds> – define validity window.
* \--pmAutoTopUp – automatically fund Paymaster deposit if required.

It verifies both account owner signatures and Paymaster signatures before sending.

**Prerequisites**

* EntryPoint deployed and registered.
* Paymaster staked and funded on-chain.
* Verifying signer is configured on-chain and locally available.

**Outputs & Diagnostics**

* Logs PVG components and computed hashes.
* Signature length and recovery checks.
* Detailed failure dumps for gas or validation errors.

**Example Workflow**

1. Start Bundler:

| yarn bundler --config ./localconfig/bundler.config.json --unsafe --auto |
| ----------------------------------------------------------------------- |

2. Send UserOperation with Paymaster:

| <p>yarn runop \<br>  --deployFactory \<br>  --network <http://localhost:18545> \<br>  --entryPoint 0x5FF1...2789 \<br>  --paymaster 0xAaBb...1122 \<br>  --verifierMnemonic ./verifier.txt \<br>  --pmValidFor 300 \<br>  --pmAutoTopUp</p> |
| ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |

3. paymasterAndData Layout:

0x<20-byte paymaster address>

\<validUntil: 48 bits>

\<validAfter: 48 bits>

\<signature: dynamic length>

### 3. Benefits to the User

* Gasless Transactions: Users interact without holding native tokens.
* Custom Sponsorship Policies: Time-bound or conditional approvals.
* Diagnostics & Security: Strong validation checks and transparent failure reporting.
* Future-proof: Compatible with ERC-4337 tooling and SDKs.


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