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bitcoinbook/code/ec-math.py
David A. Harding 2f0d7d8c3a Revert CC-BY-SA material added since the second edition
The commit ab5ae32bae is the last commit
for the second edition, so all changes since then are dropped except for
several commits for the third edition authored by Andreas Antonopoulos.

No attempt is made to remove CC-BY-SA or other licensed content present
in the already-published first or second editions.

This revert may itself be reverted for versions of the book published
under CC-BY-SA.
2023-02-01 06:31:10 -10:00

60 lines
1.8 KiB
Python

import ecdsa
import os
# secp256k1, http://www.oid-info.com/get/1.3.132.0.10
_p = 0xFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFEFFFFFC2F
_r = 0xFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFEBAAEDCE6AF48A03BBFD25E8CD0364141
_b = 0x0000000000000000000000000000000000000000000000000000000000000007
_a = 0x0000000000000000000000000000000000000000000000000000000000000000
_Gx = 0x79BE667EF9DCBBAC55A06295CE870B07029BFCDB2DCE28D959F2815B16F81798
_Gy = 0x483ada7726a3c4655da4fbfc0e1108a8fd17b448a68554199c47d08ffb10d4b8
curve_secp256k1 = ecdsa.ellipticcurve.CurveFp(_p, _a, _b)
generator_secp256k1 = ecdsa.ellipticcurve.Point(curve_secp256k1, _Gx, _Gy, _r)
oid_secp256k1 = (1, 3, 132, 0, 10)
SECP256k1 = ecdsa.curves.Curve("SECP256k1", curve_secp256k1,
generator_secp256k1, oid_secp256k1)
ec_order = _r
curve = curve_secp256k1
generator = generator_secp256k1
def random_secret():
convert_to_int = lambda array: int("".join(array).encode("hex"), 16)
# Collect 256 bits of random data from the OS's cryptographically secure
# random number generator
byte_array = os.urandom(32)
return convert_to_int(byte_array)
def get_point_pubkey(point):
if (point.y() % 2) == 1:
key = '03' + '%064x' % point.x()
else:
key = '02' + '%064x' % point.x()
return key.decode('hex')
def get_point_pubkey_uncompressed(point):
key = ('04' +
'%064x' % point.x() +
'%064x' % point.y())
return key.decode('hex')
# Generate a new private key.
secret = random_secret()
print("Secret: ", secret)
# Get the public key point.
point = secret * generator
print("EC point:", point)
print("BTC public key:", get_point_pubkey(point).encode("hex"))
# Given the point (x, y) we can create the object using:
point1 = ecdsa.ellipticcurve.Point(curve, point.x(), point.y(), ec_order)
assert(point1 == point)