C 301: Blockchains (15 pts.)

What you need

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.

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.

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