15_ECC_Real_World.py

from tinyec import registry

curve = registry.get_curve('secp192r1')
print('curve:', curve)

for k in range(0, 10):
    p = k * curve.g
    print(f"{k} * G = ({p.x}, {p.y})")

print("Cofactor =", curve.field.h)

print('Cyclic group order =', curve.field.n)

nG = curve.field.n * curve.g
print(f"n * G = ({nG.x}, {nG.y})")





# Compressing a EC point

from nummaster.basic import sqrtmod

def compress_point(point):
    return (point[0], point[1] % 2)

def uncompress_point(compressed_point, p, a, b):
    x, is_odd = compressed_point
    y = sqrtmod(pow(x, 3, p) + a * x + b, p)
    if bool(is_odd) == bool(y & 1):
        return (x, y)
    return (x, p - y)