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