Bitcoin Keys and Addresses

#!/usr/bin/env python3
# -*- coding: utf-8 -*-
import hashlib
import base58
from typing import Union


def scrub_input(hex_str_or_bytes: Union[str, bytes]) -> bytes:
    if isinstance(hex_str_or_bytes, str):
        hex_str_or_bytes = bytes.fromhex(hex_str_or_bytes)
    return hex_str_or_bytes


# wallet import format key - base58 encoded format
# https://bitcoin.stackexchange.com/questions/9244/private-key-to-wif
def gen_wif_key(private_key: Union[str, bytes], compressed_WIF: bool = False) -> bytes:
    private_key = scrub_input(private_key)

    # prepended mainnet version byte to private key
    mainnet_private_key = b'\x80' + private_key
    if compressed_WIF:
        mainnet_private_key = b'\x80' + private_key + b'\x01'
    # perform SHA-256 hash on the mainnet_private_key
    sha256 = hashlib.sha256()
    sha256.update(mainnet_private_key)
    hash = sha256.digest()

    # perform SHA-256 on the previous SHA-256 hash
    sha256 = hashlib.sha256()
    sha256.update(hash)
    hash = sha256.digest()

    # create a checksum using the first 4 bytes of the previous SHA-256 hash
    # append the 4 checksum bytes to the mainnet_private_key
    checksum = hash[:4]

    hash = mainnet_private_key + checksum

    # convert mainnet_private_key + checksum into base58 encoded string
    return base58.b58encode(hash)


def decode_wif(wif: str) -> bytes:
    compressed = False
    if wif.startswith('K') or wif.startswith('L'):
        compressed = True
    decoded = base58.b58decode(wif)
    if compressed:
        private_key = decoded[1:-5]  # [80 xxx 1 checksum]
    else:
        private_key = decoded[1:-4]  # [80 xxx checksum]
    return private_key


prikey = '0c28fca386c7a227600b2fe50b7cae11ec86d3bf1fbe471be89827e19d72aa1d'  # hex
wif = gen_wif_key(prikey)
print(wif)  # 5HueCGU8rMjxEXxiPuD5BDku4MkFqeZyd4dZ1jvhTVqvbTLvyTJ
wif_compressed = gen_wif_key(prikey, True)
print(wif_compressed)  # KwdMAjGmerYanjeui5SHS7JkmpZvVipYvB2LJGU1ZxJwYvP98617

prikey = decode_wif('5HueCGU8rMjxEXxiPuD5BDku4MkFqeZyd4dZ1jvhTVqvbTLvyTJ')
print(prikey.hex())  # 0c28fca386c7a227600b2fe50b7cae11ec86d3bf1fbe471be89827e19d72aa1d

import ecdsa
from ecdsa.ellipticcurve import PointJacobi


def derive_public_key(private_key: bytes, compressed: bool = False) -> bytes:
    Q: PointJacobi = int.from_bytes(private_key, byteorder='big') * ecdsa.curves.SECP256k1.generator
    xstr: bytes = Q.x().to_bytes(32, byteorder='big')
    ystr: bytes = Q.y().to_bytes(32, byteorder='big')
    if compressed:
        parity: int = Q.y() & 1
        return (2 + parity).to_bytes(1, byteorder='big') + xstr
    else:
        return b'\04' + xstr + ystr


prikey = bytearray.fromhex('1e99423a4ed27608a15a2616a2b0e9e52ced330ac530edcc32c8ffc6a526aedd')
uncompressed_pubkey = derive_public_key(prikey, False)
print("uncompressed public key =", uncompressed_pubkey.hex())
compressed_pubkey = derive_public_key(prikey, True)
print("compressed public key =", compressed_pubkey.hex())

#!/usr/bin/env python3
# -*- coding: utf-8 -*-

import hashlib
import base58


def sha256(inputs: bytes) -> bytes:
    """ Computes sha256 """
    sha = hashlib.sha256()
    sha.update(inputs)
    return sha.digest()


def ripemd160(inputs: bytes) -> bytes:
    """ Computes ripemd160 """
    rip = hashlib.new('ripemd160')
    rip.update(inputs)
    return rip.digest()


def base58_cksum(inputs: bytes) -> bytes:
    """ Computes base 58 four bytes check sum """
    s1 = sha256(inputs)
    s2 = sha256(s1)
    checksum = s2[0:4]
    return checksum


def pubkey_compressed_to_uncompressed(compressed_pubkey: bytes) -> bytes:
    """ Converts compressed pubkey to uncompressed format """
    assert len(compressed_pubkey) == 33
    # modulo p which is defined by secp256k1's spec
    p = 0xFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFEFFFFFC2F
    x = int.from_bytes(compressed_pubkey[1:33], byteorder='big')
    y_sq = (pow(x, 3, p) + 7) % p
    y = pow(y_sq, (p + 1) // 4, p)
    if compressed_pubkey[0] % 2 != y % 2:
        y = p - y
    y_bytes = y.to_bytes(32, byteorder='big')
    return b'\04' + compressed_pubkey[1:33] + y_bytes  # x + y


def pubkey_to_p2pkh_addr(pubkey: bytes, version: bytes) -> bytes:
    """ Derives legacy (p2pkh) address from pubkey """
    out1 = sha256(pubkey)
    out2 = ripemd160(out1)
    # Base-58 encoding with a checksum
    checksum = base58_cksum(version + out2)
    address = base58.b58encode(version + out2 + checksum)
    return address


pubkey = '03f028892bad7ed57d2fb57bf33081d5cfcf6f9ed3d3d7f159c2e2fff579dc341a'

pubkey_uncompressed = b''
pubkey_compressed = b''

if pubkey.startswith('04'):  # uncompressed
    pubkey_uncompressed = bytes.fromhex(pubkey)
    if ord(bytearray.fromhex(pubkey[-2:])) % 2 == 0:
        pubkey_compressed_hex_str = '02' + pubkey[2:66]
    else:
        pubkey_compressed_hex_str = '03' + pubkey[2:66]
    pubkey_compressed = bytes.fromhex(pubkey_compressed_hex_str)
else:  # compressed
    pubkey_uncompressed = pubkey_compressed_to_uncompressed(bytes.fromhex(pubkey))
    pubkey_compressed = bytes.fromhex(pubkey)

print("compressed public key =", pubkey_compressed.hex())
print("uncompressed public key =", pubkey_uncompressed.hex())
version = b'\x00'  # 0x00 for mainnet, 0x6f for testnet
addr_compressed = pubkey_to_p2pkh_addr(pubkey_compressed, version)
addr_uncompressed = pubkey_to_p2pkh_addr(pubkey_uncompressed, version)
print("address (uncompressed) = ", addr_uncompressed)  # 1424C2F4bC9JidNjjTUZCbUxv6Sa1Mt62x
print("address (compressed) = ", addr_compressed)  # 1J7mdg5rbQyUHENYdx39WVWK7fsLpEoXZy

#!/usr/bin/env python3
# -*- coding: utf-8 -*-
import hashlib
import base58


def sha256(inputs: bytes) -> bytes:
    """ Computes sha256 """
    sha = hashlib.sha256()
    sha.update(inputs)
    return sha.digest()


def ripemd160(inputs: bytes) -> bytes:
    """ Computes ripemd160 """
    rip = hashlib.new('ripemd160')
    rip.update(inputs)
    return rip.digest()


def base58_cksum(inputs: bytes) -> bytes:
    """ Computes base 58 four bytes check sum """
    s1 = sha256(inputs)
    s2 = sha256(s1)
    checksum = s2[0:4]
    return checksum


def pubkey_to_p2sh_p2wpkh_addr(pubkey_compressed: bytes) -> bytes:
    """ Derives p2sh-segwit (p2sh p2wpkh) address from pubkey """
    pubkey_hash = sha256(pubkey_compressed)
    rip = ripemd160(pubkey_hash)
    redeem_script = b'\x00\x14' + rip  # 0x00: OP_0, 0x14: PushData
    redeem_hash = sha256(redeem_script)
    redeem_rip = ripemd160(redeem_hash)
    # Base-58 encoding with a checksum
    version = b'\x05'  # 0x05 for mainnet, 0xc4 for testnet
    checksum = base58_cksum(version + redeem_rip)
    address = base58.b58encode(version + redeem_rip + checksum)
    return address


pubkey = '03f028892bad7ed57d2fb57bf33081d5cfcf6f9ed3d3d7f159c2e2fff579dc341a'
addr_p2sh_segwit = pubkey_to_p2sh_p2wpkh_addr(bytes.fromhex(pubkey))
print("p2sh-segwit address", addr_p2sh_segwit)  # 3FyC6EYuxW22uj4CaEGjNCjxeg7gHyFeVv

#!/usr/bin/env python3
# -*- coding: utf-8 -*-
import hashlib
from typing import Optional


def sha256(inputs: bytes) -> bytes:
    """ Computes sha256 """
    sha = hashlib.sha256()
    sha.update(inputs)
    return sha.digest()


def ripemd160(inputs: bytes) -> bytes:
    """ Computes ripemd160 """
    rip = hashlib.new('ripemd160')
    rip.update(inputs)
    return rip.digest()


# From https://github.com/sipa/bech32/blob/master/ref/python/segwit_addr.py
"""Reference implementation for Bech32 and segwit addresses."""
CHARSET = "qpzry9x8gf2tvdw0s3jn54khce6mua7l"

def bech32_polymod(values):
    """Internal function that computes the Bech32 checksum."""
    generator = [0x3b6a57b2, 0x26508e6d, 0x1ea119fa, 0x3d4233dd, 0x2a1462b3]
    chk = 1
    for value in values:
        top = chk >> 25
        chk = (chk & 0x1ffffff) << 5 ^ value
        for i in range(5):
            chk ^= generator[i] if ((top >> i) & 1) else 0
    return chk


def bech32_hrp_expand(hrp):
    """Expand the HRP into values for checksum computation."""
    return [ord(x) >> 5 for x in hrp] + [0] + [ord(x) & 31 for x in hrp]


def bech32_verify_checksum(hrp, data):
    """Verify a checksum given HRP and converted data characters."""
    return bech32_polymod(bech32_hrp_expand(hrp) + data) == 1


def bech32_create_checksum(hrp, data):
    """Compute the checksum values given HRP and data."""
    values = bech32_hrp_expand(hrp) + data
    polymod = bech32_polymod(values + [0, 0, 0, 0, 0, 0]) ^ 1
    return [(polymod >> 5 * (5 - i)) & 31 for i in range(6)]


def bech32_encode(hrp, data):
    """Compute a Bech32 string given HRP and data values."""
    combined = data + bech32_create_checksum(hrp, data)
    return hrp + '1' + ''.join([CHARSET[d] for d in combined])


def bech32_decode(bech):
    """Validate a Bech32 string, and determine HRP and data."""
    if ((any(ord(x) < 33 or ord(x) > 126 for x in bech)) or
            (bech.lower() != bech and bech.upper() != bech)):
        return (None, None)
    bech = bech.lower()
    pos = bech.rfind('1')
    if pos < 1 or pos + 7 > len(bech) or len(bech) > 90:
        return (None, None)
    if not all(x in CHARSET for x in bech[pos+1:]):
        return (None, None)
    hrp = bech[:pos]
    data = [CHARSET.find(x) for x in bech[pos+1:]]
    if not bech32_verify_checksum(hrp, data):
        return (None, None)
    return (hrp, data[:-6])


def convertbits(data, frombits, tobits, pad=True):
    """General power-of-2 base conversion."""
    acc = 0
    bits = 0
    ret = []
    maxv = (1 << tobits) - 1
    max_acc = (1 << (frombits + tobits - 1)) - 1
    for value in data:
        if value < 0 or (value >> frombits):
            return None
        acc = ((acc << frombits) | value) & max_acc
        bits += frombits
        while bits >= tobits:
            bits -= tobits
            ret.append((acc >> bits) & maxv)
    if pad:
        if bits:
            ret.append((acc << (tobits - bits)) & maxv)
    elif bits >= frombits or ((acc << (tobits - bits)) & maxv):
        return None
    return ret


def decode(hrp, addr):
    """Decode a segwit address."""
    hrpgot, data = bech32_decode(addr)
    if hrpgot != hrp:
        return (None, None)
    decoded = convertbits(data[1:], 5, 8, False)
    if decoded is None or len(decoded) < 2 or len(decoded) > 40:
        return (None, None)
    if data[0] > 16:
        return (None, None)
    if data[0] == 0 and len(decoded) != 20 and len(decoded) != 32:
        return (None, None)
    return (data[0], decoded)


def encode(hrp: str, witver: int, witprog: bytes) -> Optional[str]:
    """Encode a segwit address."""
    ret = bech32_encode(hrp, [witver] + convertbits(witprog, 8, 5))
    if decode(hrp, ret) == (None, None):
        return None
    return ret

def pubkey_to_segwit_addr(pubkey: bytes) -> Optional[str]:
    hrp = "bc"               # "bc" for mainnet, "tb" for testnet
    witver = 0
    witprog = ripemd160(sha256(pubkey))
    addr = encode(hrp, witver, witprog)
    return addr

pubkey_hex = '0279BE667EF9DCBBAC55A06295CE870B07029BFCDB2DCE28D959F2815B16F81798'
addr = pubkey_to_segwit_addr(bytearray.fromhex(pubkey_hex))
print(addr)         # bc1qw508d6qejxtdg4y5r3zarvary0c5xw7kv8f3t4