# Vault

`IBVMVault` is a secure IBVM Bitcoin vault contract that allows users to deposit BTC and enables authorized roles to perform withdrawals. It incorporates safety mechanisms like pausing and reentrancy protection, and utilizes a role-based access system.

### Inheritance

* **Pausable**: Allows the contract to be paused and unpaused by the owner.
* **ReentrancyGuard**: Protects against reentrancy attacks.

### Events

* **Deposited(address sender, uint256 amount)**: Emitted when BTC is deposited.
* **Withdrawn(address recipient, uint256 amount)**: Emitted when BTC is withdrawn.
* **OwnershipTransferred(address previousOwner, address newOwner)**: Emitted when the owner changes.
* **AdminRoleTransferred(address previousAdmin, address newAdmin)**: Emitted when the admin changes.
* **WithdrawerRoleGranted(address account)**: Emitted when an address is given the withdrawer role.
* **WithdrawerRoleRevoked(address account)**: Emitted when an address has the withdrawer role revoked.

### State Variables

* `owner (address)`: Current contract owner.
* `admin (address)`: Address with administrative capabilities.
* `hasWithdrawerRole (mapping)`: Tracks which addresses are authorized to withdraw BTC.

### Constructor

* Assigns the deployer as `owner`, `admin`, and a withdrawer.

### Modifiers

* `onlyOwner`: Restricts access to the owner.
* `onlyAdmin`: Restricts access to the admin.
* `onlyWithdrawer`: Restricts access to addresses with the withdrawer role.

### Functions

#### deposit()

```
function deposit() external payable whenNotPaused
```

* Public payable function to deposit BTC into the contract.
* Emits `Deposited` event.

#### withdraw(address recipient, uint256 amount)

```
function withdraw(address recipient, uint256 amount) external nonReentrant onlyWithdrawer whenNotPaused
```

* Transfers specified amount of BTC to a recipient.
* Restricted to addresses with withdrawer role.
* Emits `Withdrawn` event.

#### pause()

```
function pause() external onlyOwner
```

* Pauses the contract.

#### unpause()

```
function unpause() external onlyOwner
```

* Unpauses the contract.

#### transferOwnership(address newOwner)

```
function transferOwnership(address newOwner) external onlyOwner
```

* Transfers ownership to `newOwner`.
* Emits `OwnershipTransferred` event.

#### transferAdminRole(address newAdmin)

```
function transferAdminRole(address newAdmin) external onlyOwner
```

* Assigns new admin.
* Emits `AdminRoleTransferred` event.

#### grantWithdrawerRole(address account)

```
function grantWithdrawerRole(address account) external onlyAdmin
```

* Grants withdraw permission to `account`.
* Emits `WithdrawerRoleGranted` event.

#### revokeWithdrawerRole(address account)

```
function revokeWithdrawerRole(address account) external onlyAdmin
```

* Revokes withdraw permission from `account`.
* Emits `WithdrawerRoleRevoked` event.

### Security Features

* **Role-based access control**: Owner and admin can delegate or revoke access.
* **Pausable operations**: Emergency pause/unpause.
* **Reentrancy guard**: Ensures secure withdrawals.

### Usage Example

```
vault.deposit{value: 1 ether}();
vault.withdraw(0xRecipient, 1 ether);
```

### Notes

* This contract only handles BTC (native currency).
* Ensure that only trusted addresses are granted withdrawer roles.


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