Access control with OpenZeppelin in Blockchain / Solidity - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to import the AccessControl contract from OpenZeppelin.

Blockchain / Solidity

import "@openzeppelin/contracts/access/[1].sol";

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AAccessControl

BERC20

CPausable

DOwnable

Attempts:

3 left

💡 Hint

Common Mistakes

Importing Ownable instead of AccessControl.

Using ERC20 which is for tokens.

Forgetting the .sol extension.

The AccessControl contract is imported from OpenZeppelin to manage roles and permissions.

2fill in blank

medium

Complete the code to declare a role identifier for ADMIN_ROLE.

Blockchain / Solidity

bytes32 public constant ADMIN_ROLE = [1]("ADMIN_ROLE");

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Ahash256

Bsha256

Ckeccak256

DencodePacked

Attempts:

3 left

💡 Hint

Common Mistakes

Using sha256 which is different from keccak256.

Using hash256 which does not exist.

Using encodePacked which returns bytes, not bytes32.

keccak256 is used to create a unique bytes32 identifier for roles.

3fill in blank

hard

Fix the error in the constructor to grant ADMIN_ROLE to the deployer.

Blockchain / Solidity

constructor() {
    _setupRole([1], msg.sender);
}

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ADEFAULT_ADMIN_ROLE

BADMIN_ROLE

COWNER_ROLE

DMINTER_ROLE

Attempts:

3 left

💡 Hint

Common Mistakes

Using DEFAULT_ADMIN_ROLE which is different.

Using OWNER_ROLE which is not declared.

Using MINTER_ROLE which is unrelated.

The ADMIN_ROLE constant should be granted to the deployer in the constructor.

4fill in blank

hard

Fill both blanks to restrict the function to only ADMIN_ROLE holders.

Blockchain / Solidity

function restrictedAction() public [1](ADMIN_ROLE) [2] {
    // action code
}

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AonlyRole

Bpublic

Cexternal

Dview

Attempts:

3 left

💡 Hint

Common Mistakes

Using external visibility which is valid but not the intended answer here.

Using view which restricts state changes.

Omitting the onlyRole modifier.

The onlyRole modifier restricts access, and the function visibility is public.

5fill in blank

hard

Fill all three blanks to create a new role and grant it to an address.

Blockchain / Solidity

bytes32 public constant [1] = keccak256("[1]_ROLE");

function grantNewRole(address user) public [2](ADMIN_ROLE) {
    _grantRole([1], user);
}

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AMINTER

BonlyRole

DPAUSER

Attempts:

3 left

💡 Hint

Common Mistakes

Using PAUSER instead of MINTER.

Omitting the onlyRole modifier.

Mismatching role names.

The MINTER role is declared and granted using onlyRole modifier to restrict access.