unxman/pychain

basic implementation of blockchain in python

pychain

Basic implementation of a blockchain

• Chain

  • hashes data including the hash of previous blocks.
  • Chain is not a proof-of-work system

• SignedChain

  • all block hashes must begin with a given signature;
  • SignedChain is a proof-of-work blockchain system

Examples

Compute a blockchain of a few meaningless strings:

import pychain as pyc

c = pyc.SignedChain ("ab")
c.append ("no-one")
c.append ("expects")
c.append ("the spammish")
c.append ("improbabishion")

Query some aspects of the chain:

len (c)
c.is_valid ()
genesis_block_data = c[0]["data"]
expects = c[2]["data"]
spammish_hash = c[3]["hash"]

Compute a blockchain of image data from pngs (using pypng):

import pychain as pyc
import png

c = pyc.SignedChain ("fa")
c.append (png.Reader ("1.png").read ())
c.append (png.Reader ("2.png").read ())
c.append (png.Reader ("3.png").read ())

etc.

See Also

https://github.com/lhartikk/naivechain

https://medium.com/@lhartikk/a-blockchain-in-200-lines-of-code-963cc1cc0e54