flrntdfr/myblockchain

My tiny implementation of a blockchain with Processing.

Introduction

This is a tiny implementation of a blockchain. It randomly generates transactions between virtual participants and draws a modest visual representation of the blockchain. It is written in Java using the Processing environment.

In this implementation, the proof of work is the magic number to be computed for each block. It goes increasing by one 0, a block at the time (which is not realistic outside of this example).

Depedencies

Dependencies have to be saved within the code directory of the sketch.

• For SHA 256 Hashing: commons-codec-1.11.jar. (Although it could have been possible to use java.security.MessageDigest.getInstance("SHA-256"), the Apache library is more convenient to use and it better handles streams conversions.
• For the public/private key generation: Not implemented yet...

Run and visualize

1. Clone the repository
2. Make sure the sketch contains the dependency:./code/commons-codec-1.11.jar
3. Open the project in processing and run or launch it via the command line: processing-java --run --sketch=MyBlockchain
4. The sketch will be drawn on a new window at the resolution asked with the size() method.

Graphical acceleration

It is possible to consider running the algorithms on the graphical chip using the P2D renderer. However, differences in performances have not been assessed already.

Work in progress and issues to address

Related to the blockchain:

• Current implementation does not check for the balance of a participant before accepting a transaction
• Current implementation permits to easily add a transaction within a block
• Current implementation does not mine the genesis block, is that normal?
• Current implementation does not make use of public/private keys for participants
• Current implementation does not suport P2P

Related to the code:

• Consider adding public/private keywords for the variables and method fields (is not a concern with processing's pre-processor)
• Consider implementing try-catching
• Consider adding unitary tests
• Consider documenting properly the code with Javadoc