Blockchain Demo
A web-based demonstration of blockchain concepts.
This is a very basic visual introduction to the concepts behind a blockchain. We introduce the idea of an immutable ledger using an interactive web demo that is available here:
Setup
Get the code:
git clone https://github.com/anders94/blockchain-demo.git
Install dependencies:
cd blockchain-demo
npm install
Run the server:
npm start
OR
./bin/www
For windows: if the above command didn't work, use this (make sure you have Node.js installed in your system):
node ./bin/www
Point a web browser at the demo:
http://localhost:3000
Setup using Docker
Get the code:
git clone https://github.com/anders94/blockchain-demo.git
Run the Docker setup:
cd blockchain-demo
docker-compose up -d
Point a web browser at the demo:
http://localhost:3000
Optional Configuration
You can adjust the "number of zeros" required by the demo by editing the first two lines of
public/javascripts/blockchain.js.
Because there are 16 possible characters in a hex value, each time you increment the difficulty by one you make the puzzle 16 times harder. In my testing, a difficulty of 6 requires a maximumNonce well over 500,000,000.
If you adjust the difficulty above 4, blocks will show up as not mined because the demo data
assumes 4 zeros for a signed block. For example, on the http://localhost:3000/block page
with a difficulty of 6, the first nonce that works is 8719932 yielding a hash of
000000669445c22167511857d8f3b822b331c3342f25dfdcb326e35c1a7aa267.
In the production bitcoin blockchain, block 458091 has the hash digest
00000000000000000000011246f099d94f91628d71c9d75ad2f9a06e2beb7e92. That's 21 zeros in a row!
Public Private Key Demo
The 2nd part of the 101 session:
Send Thanks
Bitcoin gratefully accepted: 1K3NvcuZzVTueHW1qhkG2Cm3viRkh2EXJp