C 301: Blockchains (15 pts.)
What you need
- Any computer with a Web browser.
Purpose
To practice using a simple demonstration blockchain.
Online Tutorial
In a Web browser, go to
https://blockchaindemo.io/
Click through the demo,
as shown below.
Live Blockchain
In a Web browser, go to
https://anders.com/blockchain/blockchain.html
The demo appears,
as shown below.
At first, there is no
data stored in the blocks, and all the
blocks are valid, with green backgrounds.
Enter some data in the first block.
The background turns red, as shown below,
indicating that all the blocks are now
invalid.
In block #1, click the Mine button.
The Nonce changes as required to make the
Hash start with four zeroes, and the background
turns green, indicating that this block
is now valid.
as shown below.
Challenge: Mine This Blockchain
Put this data in the blockchain, as shown below.
- Block 1: Wally has 100 coins
- Block 2: Wally gives Sally 10 coins
- Block 3: Sally gives Billy 5 coins
Mine the blocks, as shown below.
C 301.1: Mine This Blockchain (5 pts)
The flag is the
correct nonce for block #3, covered by a gray
box in the image above.
Challenge 2: Coinbase
In the Blockchain Demo page, at the top
right, click the Coinbase tab.
Now the blocks include rewards for mining, which
come from the Coinbase, and structured transaction
data, as shown below.
Make these changes in the data, as shown below.
- Block 1: No change
- Block 2: Coinbase reward goes to Emily
- Block 3: No change
- Blocks 4 and 5: Coinbase reward halved to $50
Mine the blocks, as shown below.
C 301.2: Mine This Blockchain (10 pts)
The flag is the
correct nonce for block #5, covered by a gray
box in the image above.
Posted 6-6-18 by Sam Bowne
Updated for new scoring system 7-6-19