A basic blockchain that is leveraged as a cryptocurrency.
It written in python and implements the high level of security using hashlib. sha256 to be exact.
For all this to be put together, the flask library comes into play to create the different API endpoints for the different functions.
newblock() Create a new Block in the BlockChain :param proof: The proof given by the Proof of Work Algorithm :param previousHash: (optional) Hash of the previous block :return: New block
newTransaction() Creates a new transaction to go into the next mined block :param sender: Address of the sender :param recipient: Address of the recipient :param amount: Amount :return: The index of the Block that will hold this transaction
hash() Creates a SHA-256 hash of a Block :param block: Block :return:
lastBlock() Returns the last block in the chain
proofOfWork() Simple Proof Of Work Algorithm: -find a number 'p' such that hash(pp') contains 4 zeroes, where p is the previous p' -p is the previous proof, and p' is the new proof :param lastProof: :return:
validProof() Validates the proof: Does hash(last_proof, proof)contain 4 leading zeroes? :param lastProof: Prevoius Proof :param proof: current proof :return: True if correct, False if incorrect
registerNode() Add a new node to the list of nodes :param address: Address of the node. Eg 'http://192.168.0.5:5000' :return: None
validChain() Determine if a given blockchain is valid :param chain: A Blockchain :return: True if valid, False if not
resolveConflicts() This is our Concensus Algorithm, it resolves conflicts by replacing our chain with the longest in the network. :return: True if the chain was replaced, False if not
mine GET http://localhost:<port>/mine/
Calculate the proof of work algorithm to get the next proof.
You must receive a reward for finding the proof
Response :
{
"message": "New Block Forged",
"index": "This is the index of the new block",
"transactions": "Shows the transactions of the block",
"proof": "Proof of work",
"previousHash": "The hash of the previous block"
}new transaction POST http://localhost:<port>/transactions/new
Create a new Transaction from posted values
posted values : sender, recipient, amount
Response :
{"message" : "Transaction will be added to block {index}"}fullChain GET http://localhost:<port>/chain
Get the full chain of the blockchain.
Response :
{
"chain": "The full blockchain",
"length": "The length of the blockchain"
}register nodes POST http://localhost:<port>/nodes/register
Register new nodes to the blockchain
posted values : a of nodes
Response :
{
"message": "New nodes have been added",
"totalNodes": "A list of blockchain nodes"
}
consensus GET http://localhost:<port>/nodes/resolve
If the chain is replaced;
Response :
{
"message": "Our chain was replaced",
"newChain": "The blockchain chain"
}If the chain is not replaced;
Response :
{
"message": "Our Chain is still authoritative",
"chain": "The blockchain chain"
}