from fastecdsa import curve
from fastecdsa.point import Point
import bit

G = curve.secp256k1.G
N = curve.secp256k1.q

pk1 = '031656894a2e404e652e3a2b368c7df820b0e92fe32529c41931a9f7b234457d5b'
pk2 '022fa21d1cea4bc1f9911a9d501e3d8b3c97d15aaa76a63fecd0d529b9ef2e22f5'

def pub2point(pub_hex):
    x = int(pub_hex[2:66], 16)
    if len(pub_hex) < 70:
        y = bit.format.x_to_y(x, int(pub_hex[:2], 16) % 2)
    else:
        y = int(pub_hex[66:], 16)
    return Point(x, y, curve=curve.secp256k1)

def add(pk1, pk2, convert=True):
    if convert:
        P = pub2point(pk1)
        Q = pub2point(pk2)
    else:
        P = pk1
        Q = pk2
    R = P + Q
    return R

def sub(pk1, pk2, convert=True):
    if convert:
        P = pub2point(pk1)
        Q = pub2point(pk2)
    else:
        P = pk1
        Q = pk2
    R = P - Q
    return R


def point2pub(R):
    # Remove the following code if you are doing multiple additions successively
    # as it brings a speed improvement, and just return R
    if (R.y % 2 == 0):
        prefix = "02"
    else:
        prefix = "03"
    hx = hex(R.x)[2:].zfill(64)
    return hx

with open("input.txt") as f:
    line = f.readline()
    if line:
        P = pub2point(line)
    while line:
          line = f.readline()
          Q = pub2point(line)
          # Replace this with sub() if you want subtraction, as your last
          # post left me confused about what you want.
          P = add(P, Q, convert=False)

print(point2pub(P))

from fastecdsa import curve
from fastecdsa.point import Point
import bit

G = curve.secp256k1.G
N = curve.secp256k1.q

def pub2point(pub_hex):
    x = int(pub_hex[2:66], 16)
    if len(pub_hex) < 70:
        y = bit.format.x_to_y(x, int(pub_hex[:2], 16) % 2)
    else:
        y = int(pub_hex[66:], 16)
    return Point(x, y, curve=curve.secp256k1)



# This function makes all the downscaled pubkeys obtained from subtracting
# numbers between 0 and divisor, before dividing the pubkeys by divisor.
def shiftdown(pubkey, divisor, file, convert=True):
    Q = pub2point(pubkey) if convert else pubkey
    print(Q, 'QQ')
    # k = 1/divisor
    k = pow(divisor, N - 2, N)
    for i in range(divisor+1):
        P = Q - (i * G)
        P = k * P
        if (P.y % 2 == 0):
            prefix = "02"
        else:
            prefix = "03"
        hx = hex(P.x)[2:].zfill(64)
        hy = hex(P.y)[2:].zfill(64)
        file.write(prefix+hx+"\n") # Writes compressed key to file

factor = 32

with open("input.txt", "r") as f, open("output.txt", "w") as outf:
    line = f.readline().strip()
    while line != '':
          shiftdown(line, factor, outf)
          line = f.readline().strip()