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bitpay.find_prefix()   A

Complexity

Conditions 2

Size

Total Lines 6

Duplication

Lines 0
Ratio 0 %
Metric Value
cc 2
dl 0
loc 6
rs 9.4285
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from ecdsa import SigningKey, SECP256k1
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from ecdsa import util as ecdsaUtil
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import binascii
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import hashlib
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def generate_pem():
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    sk = SigningKey.generate(curve=SECP256k1)
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    pem = sk.to_pem()
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    pem = pem.decode("utf-8")
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    return pem
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def get_sin_from_pem(pem):
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    public_key = get_compressed_public_key_from_pem(pem)
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    version = get_version_from_compressed_key(public_key)
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    checksum = get_checksum_from_version(version)
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    return base58encode(version + checksum)
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def get_compressed_public_key_from_pem(pem):
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    vks = SigningKey.from_pem(pem).get_verifying_key().to_string()
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    bts = binascii.hexlify(vks)
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    compressed = compress_key(bts)
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    return compressed
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def sign(message, pem):
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    message = message.encode()
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    sk = SigningKey.from_pem(pem)
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    signed = sk.sign(message, hashfunc=hashlib.sha256,
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                     sigencode=ecdsaUtil.sigencode_der)
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    return binascii.hexlify(signed).decode()
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def base58encode(hexastring):
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    chars = '123456789ABCDEFGHJKLMNPQRSTUVWXYZabcdefghijkmnopqrstuvwxyz'
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    int_val = int(hexastring, 16)
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    encoded = encode58("", int_val, chars)
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    return encoded
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def encode58(string, int_val, chars):
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    if int_val == 0:
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        return string
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    else:
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        new_val, rem = divmod(int_val, 58)
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        new_string = (chars[rem]) + string
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        return encode58(new_string, new_val, chars)
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def get_checksum_from_version(version):
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    return sha_digest(sha_digest(version))[0:8]
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def get_version_from_compressed_key(key):
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    sh2 = sha_digest(key)
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    rphash = hashlib.new('ripemd160')
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    rphash.update(binascii.unhexlify(sh2))
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    rp1 = rphash.hexdigest()
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    return '0F02' + rp1
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def sha_digest(hexastring):
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    return hashlib.sha256(binascii.unhexlify(hexastring)).hexdigest()
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def compress_key(bts):
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    intval = int(bts, 16)
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    prefix = find_prefix(intval)
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    return prefix + bts[0:64].decode("utf-8")
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def find_prefix(intval):
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    if(intval % 2 == 0):
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        prefix = '02'
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    else:
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        prefix = '03'
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    return prefix
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