def test_G2_compress_and_decompress_flags(pt, on_curve, is_infinity):
if on_curve:
z1, z2 = compress_G2(pt)
x1 = z1 % POW_2_381
c_flag1 = (z1 % 2**384) // POW_2_383
b_flag1 = (z1 % POW_2_383) // POW_2_382
a_flag1 = (z1 % POW_2_382) // POW_2_381
x2 = z2 % POW_2_381
c_flag2 = (z2 % 2**384) // POW_2_383
b_flag2 = (z2 % POW_2_383) // POW_2_382
a_flag2 = (z2 % POW_2_382) // POW_2_381
assert x1 < q
assert x2 < q
assert c_flag2 == b_flag2 == a_flag2 == 0
assert c_flag1 == 1
if is_infinity:
assert b_flag1 == 1
assert a_flag1 == x1 == x2 == 0
else:
assert b_flag1 == 0
_, y = normalize(pt)
_, y_im = y.coeffs
# TODO: need a case for y_im == 0
assert a_flag1 == (y_im * 2) // q
# Correct flags should decompress correct x, y
normalize(decompress_G2((z1, z2))) == normalize(pt)
else:
with pytest.raises(ValueError):
compress_G2(pt)
def OpBLS_Decompress_G2(arg):
op = json.loads(arg)
compressed = [to_int(op['g1_x']), to_int(op['g1_y'])]
try:
point = decompress_G2(compressed)
except ValueError:
r = json.dumps([['0', '0'], ['0', '0']])
return bytes(r, 'utf-8')
x = point[0] / point[2]
y = point[1] / point[2]
point = [[str(x.coeffs[0]), str(y.coeffs[0])],
[str(x.coeffs[1]), str(y.coeffs[1])]]
r = json.dumps(point)
return bytes(r, 'utf-8')
def test_decompress_G2_edge_case(z, error_message):
if error_message is None:
decompress_G2(z)
else:
with pytest.raises(ValueError, match=error_message):
decompress_G2(z)