diff --git a/findmy/util/crypto.py b/findmy/util/crypto.py index 7d2696d..e14c206 100644 --- a/findmy/util/crypto.py +++ b/findmy/util/crypto.py @@ -1,71 +1,11 @@ """Pure-python NIST P-224 Elliptic Curve cryptography. Used for some Apple algorithms.""" from cryptography.hazmat.primitives import hashes -from cryptography.hazmat.primitives.asymmetric import ec from cryptography.hazmat.primitives.kdf.x963kdf import X963KDF ECPoint = tuple[float, float] -P224_A = 0xFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFEFFFFFFFFFFFFFFFFFFFFFFFE P224_N = 0xFFFFFFFFFFFFFFFFFFFFFFFFFFFF16A2E0B8F03E13DD29455C5C2A3D -P224_G = ( - 0xB70E0CBD6BB4BF7F321390B94A03C1D356C21122343280D6115C1D21, - 0xBD376388B5F723FB4C22DFE6CD4375A05A07476444D5819985007E34, -) -P224_P = 0xFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF000000000000000000000001 - - -# Old code. Remove if replacement is confirmed to be working. -# ruff: noqa: ERA001 -# -# def _ec_add_points(p1: ECPoint, p2: ECPoint) -> ECPoint: -# """ -# Add two points on a P-224 elliptic curve. (0, 0) is identity. -# -# https://en.wikipedia.org/wiki/Elliptic_curve_point_multiplication#Point_addition -# """ -# (x1, y1), (x2, y2) = p1, p2 -# -# if p1 == (0, 0): # identity case 1 -# return p2 -# if p2 == (0, 0): # identity case 2 -# return p1 -# if x1 == x2 and y1 == -1 * y2: # additive inverse -# return 0, 0 -# -# if p1 == p2: # point doubling using limit -# slope = (3 * x1 ** 2 + P224_A) / (2 * y1) -# else: -# slope = (y2 - y1) / (x2 - x1) -# -# x = slope ** 2 - x1 - x2 -# y = slope * (x1 - x) - y1 -# -# return x, y -# -# -# def _ec_scalar_mul(scalar: int, p: ECPoint) -> ECPoint: -# """ -# Scalar multiplication on a point on a P-224 elliptic curve. -# -# https://en.wikipedia.org/wiki/Elliptic_curve_point_multiplication#Double-and-add -# """ -# res = (0, 0) -# cur = p -# while scalar > 0: -# if scalar & 1: -# res = _ec_add_points(res, cur) -# cur = _ec_add_points(cur, cur) -# scalar >>= 1 -# return res -# -# -# def derive_ps_key(pubkey: ECPoint, sk: bytes) -> ECPoint: -# at = _x963_kdf(sk, b"diversify", 72) -# u = int.from_bytes(at[:36], "big") % (P224_N - 1) + 1 -# v = int.from_bytes(at[36:], "big") % (P224_N - 1) + 1 -# -# return _ec_add_points(_ec_scalar_mul(u, pubkey), _ec_scalar_mul(v, P224_G)) def x963_kdf(value: bytes, si: bytes, length: int) -> bytes: @@ -98,9 +38,3 @@ def derive_ps_key(privkey: bytes, sk: bytes) -> bytes: key = (u * priv_int + v) % P224_N return key.to_bytes(28, "big") - - -def _get_pubkey(privkey: int) -> ECPoint: - key = ec.derive_private_key(privkey, ec.SECP224R1()) - pubkey = key.public_key().public_numbers() - return pubkey.x, pubkey.y