amadhurkant

# ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
# ~~~ Construction of an Isogeny Between Elliptic Curves         ~~~
# ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

# Field and Curve Definitions
p = 97
F = GF(p)
E1 = EllipticCurve(F, [1, 24]) 
E2 = EllipticCurve(F, [42, 46])

amadhurkant

import libnum
from typing import List, Optional


def modular_square_roots(a: int, p: int) -> Optional[List[int]]:
    """Return all x such that x² ≡ a (mod p), or None if none exist."""
    if not libnum.has_sqrtmod_prime_power(a, p):
        return None
    return list(libnum.sqrtmod_prime_power(a, p))