def custom_hash(*args) -> bytes:
m = hashlib.sha256()
for arg in args:
if isinstance(arg, tuple) and len(arg) == 3:
m.update(compress_G1(arg).to_bytes(48, "big", signed=False))
elif isinstance(arg, int):
m.update(arg.to_bytes(8, "big", signed=False))
elif isinstance(arg, FQ):
m.update(arg.n.to_bytes(32, "big", signed=False))
else:
m.update(arg)
hash_in_bytes = m.digest()
hash_in_Fr = Fr(int.from_bytes(hash_in_bytes, "big"))
return hash_in_Fr
def OpBLS_Compress_G1(arg):
op = json.loads(arg)
x = to_int(op['g1_x'])
y = to_int(op['g1_y'])
if (x % MOD, y % MOD) == (0, 0):
return
g1 = [FQ(x), FQ(y), FQ.one()]
compressed = compress_G1(g1)
if is_valid([x, y]) == True and is_on_curve(g1, b):
decompressed = decompress_G1(compressed)
assert g1[0] == decompressed[0] and g1[1] == decompressed[1]
r = json.dumps(str(compressed))
return bytes(r, 'utf-8')
def test_G1_compress_and_decompress_flags(pt, on_curve, is_infinity):
assert on_curve == is_on_curve(pt, b)
z = compress_G1(pt)
if on_curve:
x = z % POW_2_381
c_flag = (z % 2**384) // POW_2_383
b_flag = (z % POW_2_383) // POW_2_382
a_flag = (z % POW_2_382) // POW_2_381
assert x < q
assert c_flag == 1
if is_infinity:
assert b_flag == 1
assert a_flag == x == 0
else:
assert b_flag == 0
pt_x, pt_y = normalize(pt)
assert a_flag == (pt_y.n * 2) // q
assert x == pt_x.n
# Correct flags should decompress correct x, y
normalize(decompress_G1(z)) == normalize(pt)
else:
with pytest.raises(ValueError):
decompress_G1(z)
if is_infinity:
assert b_flag == 1
assert a_flag == x == 0
else:
assert b_flag == 0
pt_x, pt_y = normalize(pt)
assert a_flag == (pt_y.n * 2) // q
assert x == pt_x.n
# Correct flags should decompress correct x, y
normalize(decompress_G1(z)) == normalize(pt)
else:
with pytest.raises(ValueError):
decompress_G1(z)
compressed_g1 = compress_G1(G1)
compressed_z1 = compress_G1(Z1)
@pytest.mark.parametrize(
'z, error_message',
[
(compressed_g1, None), # baseline
(compressed_g1 & ~(1 << 383), "c_flag should be 1"), # set c_flag to 0
(compressed_g1 | (1 << 382), "b_flag should be 0"), # set b_flag to 1
(compressed_z1 & ~(1 << 382), "b_flag should be 1"), # set b_flag to 0
(compressed_z1 | (1 << 381),
"a point at infinity should have a_flag == 0"), # set a_flag to 1
])
def test_decompress_G1_edge_case(z, error_message):
if error_message is None: