pico-blockchain

Blockchain implementation in Python for fun.

Features:

• Human readable JSON-based protocol
• In/out transactions & fast verification using UTXO
• Built-in miner
• P2P communication
• Syncing the block tree to new clients on connect
• RSA2048 keys and SHA256 hashes

Basic usage:

$ python.py picoblockchain.py <listening port> <peer address:port> <peer address:port> ...

For example, to listen on port 44444 and connect to another peer on localhost port 44445, use:

$ python.py picoblockchain.py 44444 localhost:44445

This will automatically generate your address, start a miner and start a prompt where you can issue some commands:

• send <amount> <address> to send amount coins to address
• address to view your own address
• balance to view your balance
• reorg to perform a manual reorganization (recalculation of UTXO)
• quit to stop the program

Pip dependencies:

• twisted
• pycrypto
• simplejson

What is NOT implemented

• Variable proof of work difficulty (difficulty is fixed now, so more nodes = more blocks)
• Spending coins from unverified transactions
• Disk persistance (quit the program = coins gone)
• Miner fees
• Much more

Help

It's generating many blocks, really fast

Try increasing the DIFFICULTY on top of the file. You need to do this for all nodes for them to be compatible.

When I send coins, they don't arrive

Unverified coins do not show up on the balance. Wait for the next block.

When I restart the program, my coins are gone

Disk persistence is not implemented. Keys are kept in memory and are lost on a restart.

License

Mozilla Public License Version 2.0