def _hsig_input(self, index):
'''
inputs for the hsig hash
'''
hsig_input = z.ZcashByteData()
hsig_input += self.tx_joinsplits[index].random_seed
hsig_input += self.tx_joinsplits[index].nullifiers
hsig_input += self.joinsplit_pubkey
return hsig_input.to_bytes()
def _hash_prevouts(self, anyone_can_pay: bool) -> bytes:
if anyone_can_pay:
return b'\x00' * 32
data = z.ZcashByteData()
for tx_in in self.tx_ins:
data += tx_in.outpoint
return utils.blake2b(data=data.to_bytes(),
digest_size=32,
person=b'ZcashPrevoutHash')
def _sighash_final_hashing(self, copy_tx, sighash_type):
'''
SproutTx, int -> bytes
Returns the hash that should be signed
https://en.bitcoin.it/wiki/OP_CHECKSIG#Procedure_for_Hashtype_SIGHASH_ANYONECANPAY
'''
sighash = z.ZcashByteData()
sighash += copy_tx.to_bytes()
sighash += utils.i2le_padded(sighash_type, 4)
return utils.hash256(sighash.to_bytes())
def _hash_sequence(self, sighash_type: int, anyone_can_pay: bool) -> bytes:
if anyone_can_pay or sighash_type == shared.SIGHASH_SINGLE:
return b'\x00' * 32
data = z.ZcashByteData()
for tx_in in self.tx_ins:
data += tx_in.sequence
return utils.blake2b(data=data.to_bytes(),
digest_size=32,
person=b'ZcashSequencHash')
def _hash_shielded_outputs(self) -> bytes:
if len(self.tx_shielded_outputs) == 0:
return b'\x00' * 32
data = z.ZcashByteData()
for so in self.tx_shielded_outputs:
data += so
return utils.blake2b(data=data.to_bytes(),
digest_size=32,
person=b'ZcashSOutputHash')
def _hash_shielded_spends(self) -> bytes:
if len(self.tx_shielded_spends) == 0:
return b'\x00' * 32
data = z.ZcashByteData()
for ss in self.tx_shielded_spends:
data += ss[:320] # Strip off spend_auth_sig
return utils.blake2b(data=data.to_bytes(),
digest_size=32,
person=b'ZcashSSpendsHash')
def _primary_input(self, index):
'''
Primary input for the zkproof
'''
primary_input = z.ZcashByteData()
primary_input += self.tx_joinsplits[index].anchor
primary_input += self.tx_joinsplits[index].nullifiers
primary_input += self.tx_joinsplits[index].commitments
primary_input += self.tx_joinsplits[index].vpub_old
primary_input += self.tx_joinsplits[index].vpub_new
primary_input += self.hsigs[index]
primary_input += self.tx_joinsplits[index].vmacs
return primary_input.to_bytes()
def _hash_joinsplits(self) -> bytes:
if len(self.tx_joinsplits) == 0:
return b'\x00' * 32
data = z.ZcashByteData()
for joinsplit in self.tx_joinsplits:
data += joinsplit
data += cast(bytes, self.joinsplit_pubkey)
return utils.blake2b(data=data.to_bytes(),
digest_size=32,
person=b'ZcashJSplitsHash')
def sighash(self,
sighash_type: int,
prevout_value: bytes,
index: int = 0,
joinsplit: bool = False,
script_code: Optional[bytes] = None,
anyone_can_pay: bool = False) -> bytes:
'''
ZIP243
https://github.com/zcash/zips/blob/master/zip-0243.rst
'''
if joinsplit and anyone_can_pay:
raise ValueError('ANYONECANPAY can\'t be used with joinsplits')
data = z.ZcashByteData()
data += self.header
data += self.group_id
data += self._hash_prevouts(anyone_can_pay)
data += self._hash_sequence(sighash_type, anyone_can_pay)
data += self._hash_outputs(sighash_type, index)
data += self._hash_joinsplits()
data += self._hash_shielded_spends()
data += self._hash_shielded_outputs()
data += self.lock_time
data += self.expiry_height
data += self.value_balance
if anyone_can_pay:
sighash_type = sighash_type | shared.SIGHASH_ANYONECANPAY
data += utils.i2le_padded(sighash_type, 4)
if not joinsplit:
data += self.tx_ins[index].outpoint
data += cast(bytes, script_code)
data += prevout_value
data += self.tx_ins[index].sequence
return utils.blake2b(data=data.to_bytes(),
digest_size=32,
person=b'ZcashSigHash' +
bytes.fromhex('bb09b876')) # Branch ID
def _hash_outputs(self, sighash_type: int, index: int) -> bytes:
if sighash_type not in [shared.SIGHASH_ALL, shared.SIGHASH_SINGLE]:
return b'\x00' * 32
data = z.ZcashByteData()
if sighash_type == shared.SIGHASH_ALL:
for tx_out in self.tx_outs:
data += tx_out
if sighash_type == shared.SIGHASH_SINGLE:
if index > len(self.tx_outs):
raise NotImplementedError(
'I refuse to implement the SIGHASH_SINGLE bug.')
data += self.tx_outs[index]
return utils.blake2b(data=data.to_bytes(),
digest_size=32,
person=b'ZcashOutputsHash')
def sighash(self, sighash_type, index=0, joinsplit=False, script_code=None,
anyone_can_pay=False, prevout_value=None):
'''
ZIP143
https://github.com/zcash/zips/blob/master/zip-0143.rst
'''
if joinsplit and anyone_can_pay:
raise ValueError('ANYONECANPAY can\'t be used with joinsplits')
data = z.ZcashByteData()
data += self.header
data += self.group_id
data += self._hash_prevouts(anyone_can_pay)
data += self._hash_sequence(sighash_type, anyone_can_pay)
data += self._hash_outputs(sighash_type, index)
data += self._hash_joinsplits()
data += self.lock_time
data += self.expiry_height
if anyone_can_pay:
sighash_type = sighash_type | shared.SIGHASH_ANYONECANPAY
data += utils.i2le_padded(sighash_type, 4)
if not joinsplit:
data += self.tx_ins[index].outpoint
data += script_code
data += prevout_value
data += self.tx_ins[index].sequence
return utils.blake2b(
data=data.to_bytes(),
digest_size=32,
person=b'ZcashSigHash' + bytes.fromhex('191ba85b')) # Branch ID
