78 lines
2.2 KiB
Python
78 lines
2.2 KiB
Python
import struct
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from orchard_commitments import note_commit
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from orchard_key_components import diversify_hash, prf_expand, derive_nullifier, FullViewingKey, SpendingKey
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from orchard_pallas import Point, Scalar
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from orchard_utils import to_base, to_scalar
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from utils import leos2bsp
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class OrchardNote(object):
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def __init__(self, d, pk_d, v, rho, rseed):
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assert isinstance(v, int)
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self.d = d
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self.pk_d = pk_d
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self.v = v
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self.rho = rho
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self.rseed = rseed
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self.rcm = self.rcm()
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self.psi = self.psi()
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def __eq__(self, other):
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if other is None:
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return False
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return (
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self.d == other.d and
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self.pk_d == other.pk_d and
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self.v == other.v and
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self.rho == other.rho and
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self.rcm == other.rcm and
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self.psi == other.psi
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)
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def rcm(self):
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return to_scalar(prf_expand(self.rseed, b'\x05' + bytes(self.rho)))
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def psi(self):
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return to_base(prf_expand(self.rseed, b'\x09' + bytes(self.rho)))
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def note_commitment(self):
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g_d = diversify_hash(self.d)
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return note_commit(self.rcm, leos2bsp(bytes(g_d)), leos2bsp(bytes(self.pk_d)), self.v, self.rho, self.psi)
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def note_plaintext(self, memo):
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return OrchardNotePlaintext(self.d, self.v, self.rseed, memo)
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# https://zips.z.cash/protocol/nu5.pdf#notept
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class OrchardNotePlaintext(object):
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def __init__(self, d, v, rseed, memo):
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self.leadbyte = bytes.fromhex('02')
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self.d = d
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self.v = v
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self.rseed = rseed
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self.memo = memo
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def __bytes__(self):
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return (
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self.leadbyte +
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self.d +
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struct.pack('<Q', self.v) +
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self.rseed +
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self.memo
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)
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def dummy_nullifier(self, rand):
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sk = SpendingKey(rand.b(32))
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fvk = FullViewingKey(sk)
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pk_d = fvk.default_pkd()
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d = fvk.default_d()
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v = 0
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rseed = rand.b(32)
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rho = Point.rand(rand).extract()
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note = OrchardNote(d, pk_d, v, rho, rseed)
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cm = note.note_commitment()
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return derive_nullifier(fvk.nk, rho, note.psi, cm)
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