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@tatdig
Forked from dooglus/public.py
Created July 29, 2019 14:54
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create Bitcoin public key from private key
#! /usr/bin/env python
class Point(object):
def __init__(self, _x, _y, _order = None): self.x, self.y, self.order = _x, _y, _order
def calc(self, top, bottom, other_x):
l = (top * inverse_mod(bottom)) % p
x3 = (l * l - self.x - other_x) % p
return Point(x3, (l * (self.x - x3) - self.y) % p)
def double(self):
if self == INFINITY: return INFINITY
return self.calc(3 * self.x * self.x, 2 * self.y, self.x)
def __add__(self, other):
if other == INFINITY: return self
if self == INFINITY: return other
if self.x == other.x:
if (self.y + other.y) % p == 0: return INFINITY
return self.double()
return self.calc(other.y - self.y, other.x - self.x, other.x)
def __mul__(self, e):
if self.order: e %= self.order
if e == 0 or self == INFINITY: return INFINITY
result, q = INFINITY, self
while e:
if e&1: result += q
e, q = e >> 1, q.double()
return result
def __str__(self):
if self == INFINITY: return "infinity"
return "04 %x %x" % (self.x, self.y)
def inverse_mod(a):
if a < 0 or a >= p: a = a % p
c, d, uc, vc, ud, vd = a, p, 1, 0, 0, 1
while c:
q, c, d = divmod(d, c) + (c,)
uc, vc, ud, vd = ud - q*uc, vd - q*vc, uc, vc
if ud > 0: return ud
return ud + p
p, INFINITY = 0xFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFEFFFFFC2FL, Point(None, None) # secp256k1
g = Point(0x79BE667EF9DCBBAC55A06295CE870B07029BFCDB2DCE28D959F2815B16F81798L, 0x483ada7726a3c4655da4fbfc0e1108a8fd17b448a68554199c47d08ffb10d4b8L,
0xFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFEBAAEDCE6AF48A03BBFD25E8CD0364141L)
secret = 0x2EE42A735AE3D0C1A7E435EF3B4731B0205A7839015E100BCC8472EE989EC887L
print ' privkey: %x\n pubkey: %s' % (secret, g * secret)
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