def _create_zeth_notes(
phi: bytes, hsig: bytes, output0: Tuple[OwnershipPublicKey, int],
output1: Tuple[OwnershipPublicKey, int]) -> Tuple[ZethNote, ZethNote]:
"""
Create two ordered ZethNotes. Used to generate new output
notes to be passed to the prover server.
"""
(recipient0, value0) = output0
(recipient1, value1) = output1
rho0 = _compute_rho_i(phi, hsig, 0)
trap_r0 = _trap_r_randomness()
note0 = ZethNote(apk=ownership_key_as_hex(recipient0),
value=int64_to_hex(value0),
rho=rho0.hex(),
trap_r=trap_r0)
rho1 = _compute_rho_i(phi, hsig, 1)
trap_r1 = _trap_r_randomness()
note1 = ZethNote(apk=ownership_key_as_hex(recipient1),
value=int64_to_hex(value1),
rho=rho1.hex(),
trap_r=trap_r1)
return note0, note1
def zeth_note_from_json_dict(parsed_zeth_note: Dict[str, str]) -> ZethNote:
note = ZethNote(
apk=parsed_zeth_note["a_pk"],
value=parsed_zeth_note["value"],
rho=parsed_zeth_note["rho"],
trap_r=parsed_zeth_note["trap_r"]
)
return note
def zeth_note_from_bytes(note_bytes: bytes) -> ZethNote:
if len(note_bytes) != (constants.NOTE_LENGTH_BYTES):
raise ValueError(
f"note_bytes len {len(note_bytes)}, "
f"(expected {constants.NOTE_LENGTH_BYTES})")
apk = note_bytes[
_APK_OFFSET_BYTES:_APK_OFFSET_BYTES + constants.APK_LENGTH_BYTES]
value = note_bytes[
_VALUE_OFFSET_BYTES:
_VALUE_OFFSET_BYTES + constants.PUBLIC_VALUE_LENGTH_BYTES]
rho = note_bytes[
_RHO_OFFSET_BYTES:_RHO_OFFSET_BYTES + constants.RHO_LENGTH_BYTES]
trap_r = note_bytes[_TRAPR_OFFSET_BYTES:]
return ZethNote(
apk=apk.hex(), value=value.hex(), rho=rho.hex(), trap_r=trap_r.hex())
def get_dummy_input_and_address(
a_pk: OwnershipPublicKey) -> Tuple[int, ZethNote]:
"""
Create a zeth note and address, for use as circuit inputs where there is no
real input.
"""
dummy_note = ZethNote(apk=ownership_key_as_hex(a_pk),
value=ZERO_UNITS_HEX,
rho=_get_dummy_rho(),
trap_r=_trap_r_randomness())
# Note that the Merkle path is not fully checked against the root by the
# circuit since the note value is 0. Hence the address used here is
# arbitrary.
dummy_note_address = 0
return (dummy_note_address, dummy_note)
def test_compute_commitment(self) -> None:
"""
Test the commitment value for a note, as computed by the circuit.
"""
apk = "44810c8d62784f5e9ce862925ebb889d1076a453677a5d73567387cd5717a402"
value = "0000000005f5e100"
rho = "0b0bb358233326ce4d346d86f9a0c3778ed8ce15efbf7640aad6e9359145659f"
r = "1e3063320fd43f2d6c456d7f1ee11b7ab486308133e2a5afe916daa4ff5357f6"
cm_expect = int(
"fdf5279335a2fa36fb0d664509808db8d02b6f05f9e5639960952a7038363cfc",
16)
cm_expect_field = cm_expect % constants.ZETH_PRIME
note = ZethNote(apk=apk, value=value, rho=rho, trap_r=r)
cm = int.from_bytes(compute_commitment(note), byteorder="big")
self.assertEqual(cm_expect_field, cm)