Parse a BIP32 encoded wallet from stdin

bip32.py

#!/usr/bin/env python3
# Parse a BIP32 encoded wallet from stdin

import sys
import base58
# https://raw.github.com/kylegibson/python-bitcoin-client/master/base58.py

def error(message):
    print("E:", message, file=sys.stderr)
    sys.exit(1)

def format(octets):
    return "".join("%02x" % octet for octet in octets)

def main():
    octets = sys.stdin.buffer.read()
    while octets[-1] in {b"\r", b"\n"}:
        octets = octets[:-1]

    if octets[:4] in {b"xprv", b"xpub", b"tprv", b"tpub"}:
        octets = base58.b58decode(octets.decode("ascii"), 82)
        octets = bytes(ord(c) for c in octets)
        octets, checksum = octets[:-4], octets[-4:]
    else:
        checksum = None

    if len(octets) != 78:
        message = "Incorrect BIP32 wallet size: expected 78 bytes, got %s bytes"
        error(message % len(octets))

    version, octets = octets[:4], octets[4:]
    node, octets = octets[:1], octets[1:]
    fingerprint, octets = octets[:4], octets[4:]
    child, octets = octets[:4], octets[4:]
    chain, key = octets[:32], octets[32:]

    print("version:", format(version))
    print("node:", format(node))
    print("fingerprint:", format(fingerprint))
    print("child:", format(child))
    print("chain:", format(chain))
    print("key:", format(key))

if __name__ == "__main__":
    main()