PROJH402: Toy blockchain

Architecture

Every node is represented by a Node object. It has its own (host, port) and must have a consensus a initialisation parameter.

Required methods to implement a new consensus

Every consensus needs the following methods/attributes:

• verify_chain(chain, previous_state): Method that verifies that the specified chain respects the consensus. The previous_state is the state of the previous block.
• self.block_generation: Specified in the constructor, this is a thread object that will produce the blocks respecting the consensus.
• self.genesis: Genesis block that will be the first block of every node using this consensus.

Custom Timer

The whole project is based on a custom timer. Each node possess its own CustomTimer. At each control step of one robot, the timer is incremented by 1.

Options

Consensus options

The consensus options are contained in their own file

Proof of work

MINING_DIFFICULTY: This represents the difficulty of mining and is thus related to the time taken to produce a block

ProofOfWork.trust: Determines if the state should be checked or not when verifying a chain

Proof of authority

BLOCK_PERIOD: Minimum difference between two consecutive block’s timestamps.

DIFF_INTURN: Block score (difficulty) for blocks containing in-turn signatures (by the preferred producer of this turn)

DIFF_NOTURN: Block score (difficulty) for blocks containing out-of-turn signatures (not by the preferred producer of this turn)

ProofOfAuth.trust: Determines if the state should be checked or not when verifying a chain

The genesis block is organised this way:

• miner_id contains the authorised signers list

Other options

All the other options are contained in the constants.py file.

MEMPOOL_SYNC_INTERVAL: Time interval between two synchronisation process in the MempoolPinger

CHAIN_SYNC_INTERVAL: Time interval between two synchronisation process in the ChainPinger