simple_blockchain

This repo was inspired by Satoshi Nakamoto's blockchain whitepaper and Aunyks's tiny blockchain implementation in Python.

Implementation

Blocks!

A block is an object that contains, in this implementation, a series of transactional data. All previous transactions are available in a ledger called the blockchain. A blockchain is a sequence of blocks agreed upon by a network of workers. Thus the integrity of the whole system can be verified by using a mathematical function in which the answer is difficult to obtain but easy to check. This mathematical check can be performed on each block all the way back to the first block. The validity of the blocks is determined by using a Proof of Work algorithm. More on that later.

Nodes

Upon startup, nodes check for peers and their respective blockchains. If no peers are found, an initial block is created. A node can process a transaction, mine, and return the blockchain upon request.

Consensus Algorithm

A blockchain is decided to be the master chain by evaluating lengths of other nodes' blockchains. The longest chain is decided to be the master blockchain. I plan to implement the consensus algorithm outlined in Nakamoto's paper which seeks the longest chain with the greatest proof of work.

Mining

Mining from a node is a transactional relationship where the miner is rewarded for completing a very simple, yet verifiable mathematical task. Similar to the Proof of Work outlined in Nakamoto's whitepaper, this implementation requires a hash be created with a specified number of leading zero bits. This hash is a result of passing a string, made by concatenating a Block's previous hash and a nonce (the constant the miner is solving for), through the SHA256 hashing function. Once the nonce is solved for, the miner is rewarded and a new block is generated.