btcpay-python/btcpay/crypto.py
2018-03-07 18:08:38 -05:00

87 lines
2.1 KiB
Python

"""btcpay.crypto
These are various crytography related utility functions borrowed from:
bitpay-python: https://github.com/bitpay/bitpay-python
"""
import binascii
import hashlib
from ecdsa import SigningKey, SECP256k1, VerifyingKey
from ecdsa import util as ecdsaUtil
def generate_privkey():
sk = SigningKey.generate(curve=SECP256k1)
pem = sk.to_pem()
pem = pem.decode('utf-8')
return pem
def get_sin_from_pem(pem):
public_key = get_compressed_public_key_from_pem(pem)
version = get_version_from_compressed_key(public_key)
checksum = get_checksum_from_version(version)
return base58encode(version + checksum)
def get_compressed_public_key_from_pem(pem):
vks = SigningKey.from_pem(pem).get_verifying_key().to_string()
bts = binascii.hexlify(vks)
compressed = compress_key(bts)
return compressed
def sign(message, pem):
message = message.encode()
sk = SigningKey.from_pem(pem)
signed = sk.sign(message, hashfunc=hashlib.sha256,
sigencode=ecdsaUtil.sigencode_der)
return binascii.hexlify(signed).decode()
def base58encode(hexastring):
chars = '123456789ABCDEFGHJKLMNPQRSTUVWXYZabcdefghijkmnopqrstuvwxyz'
int_val = int(hexastring, 16)
encoded = encode58('', int_val, chars)
return encoded
def encode58(string, int_val, chars):
if int_val == 0:
return string
else:
(new_val, rem) = divmod(int_val, 58)
new_string = chars[rem] + string
return encode58(new_string, new_val, chars)
def get_checksum_from_version(version):
return sha_digest(sha_digest(version))[0:8]
def get_version_from_compressed_key(key):
sh2 = sha_digest(key)
rphash = hashlib.new('ripemd160')
rphash.update(binascii.unhexlify(sh2))
rp1 = rphash.hexdigest()
return '0F02' + rp1
def sha_digest(hexastring):
return hashlib.sha256(binascii.unhexlify(hexastring)).hexdigest()
def compress_key(bts):
intval = int(bts, 16)
prefix = find_prefix(intval)
return prefix + bts[0:64].decode('utf-8')
def find_prefix(intval):
if intval % 2 == 0:
prefix = '02'
else:
prefix = '03'
return prefix