def test_der_deserialize() -> None:
err_msg = "non-hexadecimal number found "
with pytest.raises(ValueError, match=err_msg):
Sig.parse("not a sig")
sig = Sig(2**255 - 4, 2**247 - 1)
sig_bin = sig.serialize()
r_size = sig_bin[3]
bad_sig_bin = b"\x31" + sig_bin[1:]
err_msg = "invalid compound header: "
with pytest.raises(BTClibValueError, match=err_msg):
Sig.parse(bad_sig_bin)
bad_sig_bin = sig_bin[:1] + b"\x41" + sig_bin[2:]
err_msg = "not enough binary data"
with pytest.raises(BTClibRuntimeError, match=err_msg):
Sig.parse(bad_sig_bin)
# r and s scalars
for offset in (4, 6 + r_size):
bad_sig_bin = sig_bin[:offset - 2] + b"\x00" + sig_bin[offset - 1:]
err_msg = "invalid value header: "
with pytest.raises(BTClibValueError, match=err_msg):
Sig.parse(bad_sig_bin)
bad_sig_bin = sig_bin[:offset - 1] + b"\x00" + sig_bin[offset:]
err_msg = "zero size"
with pytest.raises(BTClibRuntimeError, match=err_msg):
Sig.parse(bad_sig_bin)
bad_sig_bin = sig_bin[:offset - 1] + b"\x80" + sig_bin[offset:]
err_msg = "not enough binary data"
with pytest.raises(BTClibRuntimeError, match=err_msg):
Sig.parse(bad_sig_bin)
bad_sig_bin = sig_bin[:offset] + b"\x80" + sig_bin[offset + 1:]
err_msg = "invalid negative scalar"
with pytest.raises(BTClibValueError, match=err_msg):
Sig.parse(bad_sig_bin)
bad_sig_bin = sig_bin[:offset] + b"\x00\x7f" + sig_bin[offset + 2:]
err_msg = "invalid 'highest bit set' padding"
with pytest.raises(BTClibValueError, match=err_msg):
Sig.parse(bad_sig_bin)
data_size = sig_bin[1]
malleated_size = (data_size + 1).to_bytes(1, byteorder="big", signed=False)
bad_sig_bin = sig_bin[:1] + malleated_size + sig_bin[2:] + b"\x01"
err_msg = "invalid DER sequence length"
with pytest.raises(BTClibValueError, match=err_msg):
Sig.parse(bad_sig_bin)
def test_der_size() -> None:
sig8 = 1, 1
sig72 = ec.n - 2, ec.n - 1
sig71 = 2**255 - 4, ec.n - 1
sig70 = 2**255 - 4, 2**255 - 1
sig70b = 2**255 - 4, 2**248 - 1
sig69 = 2**255 - 4, 2**247 - 1
sig68 = 2**247 - 1, 2**247 - 1
sigs = [sig8, sig72, sig71, sig70, sig70b, sig69, sig68]
lenghts = [8, 72, 71, 70, 70, 69, 68]
for length, (r, s) in zip(lenghts, sigs):
sig = Sig(r, s)
assert r == sig.r
assert s == sig.s
assert ec == sig.ec
sig_bin = sig.serialize()
assert len(sig_bin) == length
assert sig == Sig.parse(sig_bin)