Why blockchain exists - See It in Action

Understanding Why Blockchain Exists

📖 Scenario: Imagine you want to keep a shared list of transactions with your friends, but you don't want anyone to cheat or change the list secretly. You need a way to make sure everyone agrees on the list and no one can change past entries. This is why blockchain was created.

🎯 Goal: Build a simple program that shows how blockchain keeps data safe and agreed upon by everyone. You will create a list of blocks, add new blocks only if they follow the rules, and print the chain to see the result.

📋 What You'll Learn

Create a list called blockchain with one block containing the string 'Genesis Block'

Create a variable called new_data with the string 'Transaction 1'

Add a new block to blockchain only if new_data is not empty

Print the entire blockchain list

💡 Why This Matters

🌍 Real World

Blockchain is used to keep records safe and shared without a central boss. This helps in money transfers, contracts, and more.

💼 Career

Understanding blockchain basics is useful for jobs in finance, software development, and security where trust and data safety matter.

1

Create the initial blockchain list

Create a list called blockchain with one block containing the string 'Genesis Block'.

Blockchain / Solidity

# Create the blockchain list with the first block
# Your code here

Need a hint?

The first block is called the 'Genesis Block'. Use a list with one string inside.

2

Add new transaction data

Create a variable called new_data and set it to the string 'Transaction 1'.

Blockchain / Solidity

blockchain = ['Genesis Block']
# Create new_data with 'Transaction 1'
# Your code here

Need a hint?

Just assign the string 'Transaction 1' to the variable new_data.

3

Add new block if data is valid

Add a new block to the blockchain list only if new_data is not an empty string. Use an if statement to check this.

Blockchain / Solidity

blockchain = ['Genesis Block']
new_data = 'Transaction 1'
# Add new_data to blockchain if new_data is not empty
# Your code here

Need a hint?

Use if new_data != '' to check if new_data has content before adding it.

4

Print the blockchain

Print the blockchain list to show all blocks.

Blockchain / Solidity

blockchain = ['Genesis Block']
new_data = 'Transaction 1'
if new_data != '':
    blockchain.append(new_data)
# Print the blockchain list
# Your code here

Need a hint?

Use print(blockchain) to show the list.