Access control patterns in Blockchain / Solidity - Mini Project: Build & Apply

Access Control Patterns in Blockchain

📋 What You'll Learn

💡 Why This Matters

🌍 Real World

Access control is essential in blockchain smart contracts to restrict who can perform sensitive actions like transferring tokens or changing contract settings.

💼 Career

Understanding access control patterns is key for blockchain developers to write secure smart contracts that protect assets and data.

1

DATA SETUP: Create the initial authorized users list

Create a list called authorized_users with these exact addresses: '0x123', '0x456', and '0x789'.

Blockchain / Solidity

# Create the list authorized_users with the given addresses
# Your code here

Need a hint?

Use a Python list with the exact strings for addresses.

2

CONFIGURATION: Add the owner address variable

Create a variable called owner and set it to the exact address '0xabc'.

Blockchain / Solidity

authorized_users = ['0x123', '0x456', '0x789']
# Create the owner variable with address '0xabc'
# Your code here

Need a hint?

Just assign the string '0xabc' to the variable owner.

3

CORE LOGIC: Write a function to add authorized users by owner only

Write a function called add_authorized_user that takes parameters caller and new_user. Inside, check if caller == owner. If yes, append new_user to authorized_users. Otherwise, do nothing.

Blockchain / Solidity

authorized_users = ['0x123', '0x456', '0x789']
owner = '0xabc'
# Define add_authorized_user(caller, new_user) function
# Your code here

Need a hint?

Use an if statement to compare caller and owner, then append new_user to authorized_users.

4

OUTPUT: Check if a user is authorized and print the result

Write code to check if the address '0x456' is in authorized_users and print true or false accordingly.

Blockchain / Solidity

authorized_users = ['0x123', '0x456', '0x789']
owner = '0xabc'

def add_authorized_user(caller, new_user):
    if caller == owner:
        authorized_users.append(new_user)

# Check if '0x456' is authorized and print the result
# Your code here

Need a hint?

Use the in keyword to check membership and print the boolean result.