Esempio n. 1
0
    def build_transactions(self):
        assert self.role == Role.SELLER and self.stage == Stage.LOCK, "Incorrect stage"

        # Check output range proof
        output = Output(OutputFeatures.DEFAULT_OUTPUT, self.commit,
                        self.range_proof)
        assert output.verify(self.secp), "Invalid bulletproof"

        # Build refund tx
        refund_input = Input(OutputFeatures.DEFAULT_OUTPUT, self.commit)

        public_refund_nonce_sum = PublicKey.from_combination(
            self.secp,
            [self.public_refund_nonce, self.foreign_public_refund_nonce])

        refund_signature = aggsig.add_partials(self.secp, [
            self.partial_refund_signature,
            self.foreign_partial_refund_signature
        ], public_refund_nonce_sum)
        assert aggsig.verify(
            self.secp, refund_signature, self.public_refund_excess,
            self.refund_fee_amount,
            self.refund_lock_height), "Unable to verify refund signature"

        refund_kernel = Kernel(0, self.refund_fee_amount,
                               self.refund_lock_height, None, None)
        self.refund_tx = Transaction([refund_input], [self.refund_output],
                                     [refund_kernel], self.refund_offset)
        refund_kernel.excess = self.refund_tx.sum_commitments(self.secp)
        refund_kernel.excess_signature = refund_signature
        assert self.refund_tx.verify_kernels(
            self.secp), "Unable to verify refund kernel"

        # Build multisig tx
        public_nonce_sum = PublicKey.from_combination(
            self.secp, [self.public_nonce, self.foreign_public_nonce])

        signature = aggsig.add_partials(
            self.secp,
            [self.partial_signature, self.foreign_partial_signature],
            public_nonce_sum)
        assert aggsig.verify(self.secp, signature, self.public_excess, self.fee_amount, self.lock_height), \
            "Unable to verify signature"

        kernel = Kernel(0, self.fee_amount, self.lock_height, None, None)
        self.tx = Transaction(self.inputs, [self.change_output, output],
                              [kernel], self.offset)
        kernel.excess = self.tx.sum_commitments(self.secp)
        kernel.excess_signature = signature
        assert self.tx.verify_kernels(self.secp), "Unable to verify kernel"

        self.swap_nonce = SecretKey.random(self.secp)
        self.public_swap_nonce = self.swap_nonce.to_public_key(self.secp)
Esempio n. 2
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 def from_dict(secp: Secp256k1, dct: dict):
     return Slate(dct['num_participants'], UUID.from_str(dct['id']),
                  Transaction.from_dict(secp, dct['tx']), dct['amount'],
                  dct['fee'], dct['height'], dct['lock_height'], [
                      ParticipantData.from_dict(secp, x)
                      for x in dct['participant_data']
                  ])
    def finalize_swap(self):
        seller = self.role == Role.SELLER
        assert (seller and self.stage == Stage.DONE) or (
            not seller and self.stage == Stage.SWAP), "Incorrect stage"

        if seller:
            self.secret_lock = self.foreign_partial_swap_adaptor.scalar(
                self.secp).add(
                    self.secp,
                    self.foreign_partial_swap_signature.scalar(
                        self.secp).negate(self.secp))

            public_lock = self.secret_lock.to_public_key(self.secp)
            assert self.public_lock == public_lock, "Invalid secret lock, this should never happen"

            if self.is_ether_swap():
                self.claim = self.secp.sign_recoverable(
                    self.secret_lock, bytearray([0] * 32))
        else:
            swap_input = Input(OutputFeatures.DEFAULT_OUTPUT, self.commit)
            public_swap_nonce_sum = PublicKey.from_combination(
                self.secp,
                [self.public_swap_nonce, self.foreign_public_swap_nonce])

            swap_signature = aggsig.add_partials(self.secp, [
                self.partial_swap_signature,
                self.foreign_partial_swap_signature
            ], public_swap_nonce_sum)

            assert aggsig.verify(
                self.secp, swap_signature, self.public_swap_excess,
                self.swap_fee_amount,
                self.swap_lock_height), "Unable to verify swap signature"

            swap_kernel = Kernel(0, self.swap_fee_amount,
                                 self.swap_lock_height, None, None)
            self.swap_tx = Transaction([swap_input], [self.swap_output],
                                       [swap_kernel], self.swap_offset)
            swap_kernel.excess = self.swap_tx.sum_commitments(self.secp)
            swap_kernel.excess_signature = swap_signature
            assert self.swap_tx.verify_kernels(
                self.secp), "Unable to verify swap kernel"
Esempio n. 4
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def send(node_url: str):
    global secp, wallet, proof_builder

    now = int(time())

    send_amount = GRIN_UNIT
    lock_height = 1
    refund_lock_height = lock_height + 1440  # ~24 hours
    dest_url = "http://127.0.0.1:18185"
    fluff = True

    secp = Secp256k1(None, FLAG_ALL)
    wallet = Wallet.open(secp, "wallet_a")

    print("Preparing to create multisig with {}".format(dest_url))

    input_entries = wallet.select_outputs(send_amount +
                                          tx_fee(1, 2, MILLI_GRIN_UNIT))
    fee_amount = tx_fee(len(input_entries), 2, MILLI_GRIN_UNIT)
    input_amount = sum(x.value for x in input_entries)
    change_amount = input_amount - send_amount - fee_amount
    refund_fee_amount = tx_fee(1, 1, MILLI_GRIN_UNIT)

    print("Selected {} inputs".format(len(input_entries)))

    tx = Transaction.empty(secp, 0, fee_amount, lock_height)
    refund_tx = Transaction.empty(secp, 0, refund_fee_amount,
                                  refund_lock_height)

    blind_sum = BlindSum()

    # Inputs
    inputs = []
    for entry in input_entries:
        entry.mark_locked()
        blind_sum.sub_child_key(wallet.derive_from_entry(entry))
        input = wallet.entry_to_input(entry)
        tx.add_input(secp, input)
        inputs.append(input)

    # Change output
    change_child, change_entry = wallet.create_output(change_amount)
    blind_sum.add_child_key(change_child)
    change_output = wallet.entry_to_output(change_entry)
    tx.add_output(secp, change_output)

    # Multisig output
    partial_child, partial_entry = wallet.create_output(send_amount)
    partial_entry.mark_locked()
    blind_sum.add_child_key(partial_child)
    public_partial_commit = wallet.commit_with_child_key(0, partial_child)

    # Refund output
    refund_amount = send_amount - refund_fee_amount
    refund_child, refund_entry = wallet.create_output(refund_amount)
    refund_output = wallet.entry_to_output(refund_entry)
    refund_tx.add_output(secp, refund_output)

    # Offset
    blind_sum.sub_blinding_factor(tx.offset)

    # Excess
    excess = wallet.chain.blind_sum(blind_sum).to_secret_key(secp)
    public_excess = excess.to_public_key(secp)

    # Nonce
    nonce = SecretKey.random(secp)
    public_nonce = nonce.to_public_key(secp)

    # Refund nonce
    refund_nonce = SecretKey.random(secp)
    refund_public_nonce = refund_nonce.to_public_key(secp)

    dct = {
        "amount": send_amount,
        "fee": fee_amount,
        "refund_fee": refund_fee_amount,
        "lock_height": lock_height,
        "refund_lock_height": refund_lock_height,
        "public_partial_commit": public_partial_commit.to_hex(secp).decode(),
        "public_nonce": public_nonce.to_hex(secp).decode(),
        "refund_public_nonce": refund_public_nonce.to_hex(secp).decode()
    }

    f = open("logs/{}_multisig_1.json".format(now), "w")
    f.write(json.dumps(dct, indent=2))
    f.close()

    print("Sending to receiver..")

    req = urlopen(dest_url, json.dumps(dct).encode(), 60)
    dct2 = json.loads(req.read().decode())

    f = open("logs/{}_multisig_2.json".format(now), "w")
    f.write(json.dumps(dct2, indent=2))
    f.close()

    print("Received response, processing..")

    public_partial_commit_recv = Commitment.from_hex(
        secp, dct2['public_partial_commit'].encode())
    public_partial_recv = public_partial_commit_recv.to_public_key(secp)
    public_nonce_recv = PublicKey.from_hex(secp, dct2['public_nonce'].encode())
    public_excess_recv = public_partial_commit_recv.to_public_key(secp)
    partial_signature_recv = Signature.from_hex(
        dct2['partial_signature'].encode())
    refund_public_nonce_recv = PublicKey.from_hex(
        secp, dct2['refund_public_nonce'].encode())
    refund_public_excess_recv = PublicKey.from_hex(
        secp, dct2['refund_public_excess'].encode())
    refund_partial_signature_recv = Signature.from_hex(
        dct2['refund_partial_signature'].encode())

    # Commitment
    commit = secp.commit_sum(
        [public_partial_commit_recv,
         wallet.commit(partial_entry)], [])
    print("Total commit: {}".format(commit))

    # Nonce sums
    public_nonce_sum = PublicKey.from_combination(
        secp, [public_nonce_recv, public_nonce])
    refund_public_nonce_sum = PublicKey.from_combination(
        secp, [refund_public_nonce_recv, refund_public_nonce])

    # Step 2 of bulletproof
    proof_builder = MultiPartyBulletProof(secp, partial_child,
                                          public_partial_recv, send_amount,
                                          commit)
    t_1_recv = PublicKey.from_hex(secp, dct2['t_1'].encode())
    t_2_recv = PublicKey.from_hex(secp, dct2['t_2'].encode())
    t_1, t_2 = proof_builder.step_1()
    proof_builder.fill_step_1(t_1_recv, t_2_recv)
    tau_x = proof_builder.step_2()

    dct3 = {
        "t_1": t_1.to_hex(secp).decode(),
        "t_2": t_2.to_hex(secp).decode(),
        "tau_x": tau_x.to_hex().decode()
    }

    f = open("logs/{}_multisig_3.json".format(now), "w")
    f.write(json.dumps(dct3, indent=2))
    f.close()

    print("Sending bulletproof component..")

    req2 = urlopen(dest_url, json.dumps(dct3).encode(), 60)
    dct4 = json.loads(req2.read().decode())

    print("Received response")

    f = open("logs/{}_multisig_4.json".format(now), "w")
    f.write(json.dumps(dct4, indent=2))
    f.close()

    # Bulletproof
    proof = RangeProof.from_bytearray(
        bytearray(unhexlify(dct4['proof'].encode())))
    output = Output(OutputFeatures.DEFAULT_OUTPUT, commit, proof)
    assert output.verify(secp), "Invalid bulletproof"
    tx.add_output(secp, output)
    print("Created bulletproof")

    # First we finalize the refund tx, and check its validity
    refund_input = Input(OutputFeatures.DEFAULT_OUTPUT, commit)
    refund_tx.add_input(secp, refund_input)

    # Refund excess
    refund_blind_sum = BlindSum()
    refund_blind_sum.sub_child_key(partial_child)
    refund_blind_sum.add_child_key(refund_child)
    refund_blind_sum.sub_blinding_factor(refund_tx.offset)
    refund_excess = wallet.chain.blind_sum(refund_blind_sum).to_secret_key(
        secp)
    refund_public_excess = refund_excess.to_public_key(secp)

    # Refund partial signature
    refund_partial_signature = aggsig.calculate_partial(
        secp, refund_excess, refund_nonce, refund_public_nonce_sum,
        refund_fee_amount, refund_lock_height)

    # Refund final signature
    refund_public_excess_sum = PublicKey.from_combination(
        secp, [refund_public_excess_recv, refund_public_excess])
    refund_signature = aggsig.add_partials(
        secp, [refund_partial_signature_recv, refund_partial_signature],
        refund_public_nonce_sum)
    assert aggsig.verify(secp, refund_signature, refund_public_excess_sum, refund_fee_amount, refund_lock_height), \
        "Unable to verify refund signature"
    refund_kernel = refund_tx.kernels[0]
    refund_kernel.excess = refund_tx.sum_commitments(secp)
    refund_kernel.excess_signature = refund_signature
    assert refund_tx.verify_kernels(secp), "Unable to verify refund kernel"

    print("Refund tx is valid")

    f = open("logs/{}_refund.json".format(now), "w")
    f.write(json.dumps(refund_tx.to_dict(secp), indent=2))
    f.close()

    refund_tx_wrapper = {"tx_hex": refund_tx.to_hex(secp).decode()}

    f = open("logs/{}_refund_hex.json".format(now), "w")
    f.write(json.dumps(refund_tx_wrapper, indent=2))
    f.close()

    print("Finalizing multisig tx..")

    # Partial signature
    partial_signature = aggsig.calculate_partial(secp, excess, nonce,
                                                 public_nonce_sum, fee_amount,
                                                 lock_height)

    # Final signature
    public_excess_sum = PublicKey.from_combination(
        secp, [public_excess_recv, public_excess])
    signature = aggsig.add_partials(
        secp, [partial_signature_recv, partial_signature], public_nonce_sum)
    assert aggsig.verify(secp, signature, public_excess_sum, fee_amount,
                         lock_height), "Unable to verify signature"
    kernel = tx.kernels[0]
    kernel.excess = tx.sum_commitments(secp)
    kernel.excess_signature = signature
    assert tx.verify_kernels(secp), "Unable to verify kernel"

    f = open("logs/{}_tx.json".format(now), "w")
    f.write(json.dumps(tx.to_dict(secp), indent=2))
    f.close()

    tx_wrapper = {"tx_hex": tx.to_hex(secp).decode()}

    f = open("logs/{}_tx_hex.json".format(now), "w")
    f.write(json.dumps(tx_wrapper, indent=2))
    f.close()

    print("Submitting to node..")

    urlopen("{}/v1/pool/push".format(node_url) + ("?fluff" if fluff else ""),
            json.dumps(tx_wrapper).encode(), 600)

    wallet.save()

    print("Transaction complete!")
Esempio n. 5
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 def blank(secp: Secp256k1, num_participants: int, amount: int, height: int,
           features: int, fee: int, lock_height: int):
     slate = Slate(num_participants, UUID.random(),
                   Transaction.empty(secp, features, fee, lock_height),
                   amount, fee, height, lock_height, [])
     return slate
Esempio n. 6
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class AtomicSwap:
    def __init__(self, secp: Secp256k1, role: Role, id: UUID):
        self.secp = secp
        self.role = role
        self.id = id
        self.swap_file = absolute(
            "swap_data", "sell" if self.role is Role.SELLER else "buy",
            "{}.json".format(str(id)))

        # Default values
        self.stage = self.wallet = self.grin_amount = self.swap_currency = self.swap_amount \
            = self.swap_receive_address = self.swap_cosign = self.public_swap_cosign = self.lock_height \
            = self.refund_lock_height = self.input_entries = self.inputs = self.fee_amount = self.refund_fee_amount \
            = self.input_amount = self.change_amount = self.change_entry = self.change_child = self.change_output \
            = self.partial_entry = self.partial_child = self.partial_commit = self.offset = self.public_excess \
            = self.refund_entry = self.refund_child = self.refund_output = self.refund_offset = self.nonce \
            = self.public_nonce = self.refund_nonce = self.public_refund_nonce = self.foreign_partial_commit \
            = self.foreign_public_nonce = self.foreign_public_refund_nonce = self.secret_lock \
            = self.public_lock = self.eth_address_lock = self.eth_contract_address = self.btc_lock_time \
            = self.btc_refund_key = self.public_btc_refund_key = self.btc_lock_address = self.commit \
            = self.public_refund_excess = self.partial_signature = self.partial_refund_signature = self.t_1 = self.t_2 \
            = self.foreign_partial_signature = self.foreign_partial_refund_signature = self.foreign_t_1 \
            = self.foreign_t_2 = self.tau_x = self.foreign_tau_x = self.range_proof = self.refund_tx = self.tx \
            = self.tx_height = self.btc_output_points = self.swap_nonce = self.public_swap_nonce \
            = self.foreign_public_swap_nonce = self.swap_entry = self.swap_child = self.swap_fee_amount \
            = self.swap_lock_height = self.swap_output = self.swap_offset = self.public_swap_excess \
            = self.partial_swap_signature = self.partial_swap_adaptor \
            = self.foreign_partial_swap_adaptor = self.foreign_partial_swap_signature = self.swap_tx \
            = self.claim = None
        self.time_start = int(time())

        if os.path.exists(self.swap_file):
            self.load()

    def is_bitcoin_swap(self) -> bool:
        return self.swap_currency == "BTC"

    def is_ether_swap(self) -> bool:
        return self.swap_currency == "ETH"

    def select_inputs(self):
        assert self.stage is None, "Incorrect stage"
        assert self.role == Role.SELLER, "Incorrect role"

        self.stage = Stage.INIT

        if self.is_bitcoin_swap():
            # Generate a key that will co-sign the BTC multisig
            self.swap_cosign = SecretKey.random(self.secp)
            self.public_swap_cosign = self.swap_cosign.to_public_key(self.secp)

        # Inputs
        self.input_entries = self.wallet.select_outputs(
            self.grin_amount + tx_fee(1, 2, MILLI_GRIN_UNIT) + 1)
        self.inputs = []
        for entry in self.input_entries:
            entry.mark_locked()
            input = self.wallet.entry_to_input(entry)
            self.inputs.append(input)
        self.fee_amount = tx_fee(len(self.input_entries), 2, MILLI_GRIN_UNIT)
        self.refund_fee_amount = tx_fee(1, 1, MILLI_GRIN_UNIT)
        self.input_amount = sum(x.value for x in self.input_entries)
        self.change_amount = self.input_amount - self.grin_amount - self.fee_amount

        # Change output
        self.change_child, self.change_entry = self.wallet.create_output(
            self.change_amount)
        self.change_entry.mark_locked()
        self.change_output = self.wallet.entry_to_output(self.change_entry)

        # Partial multisig output
        self.partial_child, self.partial_entry = self.wallet.create_output(
            self.grin_amount)
        self.partial_entry.mark_locked()
        self.partial_commit = self.wallet.commit_with_child_key(
            0, self.partial_child)

        # Offset
        self.offset = BlindingFactor.from_secret_key(
            SecretKey.random(self.secp))

        # Refund output
        refund_amount = self.grin_amount - self.refund_fee_amount
        self.refund_child, self.refund_entry = self.wallet.create_output(
            refund_amount)
        self.refund_output = self.wallet.entry_to_output(self.refund_entry)

        # Refund offset
        self.refund_offset = BlindingFactor.from_secret_key(
            SecretKey.random(self.secp))

        # Nonces
        self.nonce = SecretKey.random(self.secp)
        self.public_nonce = self.nonce.to_public_key(self.secp)
        self.refund_nonce = SecretKey.random(self.secp)
        self.public_refund_nonce = self.refund_nonce.to_public_key(self.secp)

        self.wallet.save()

    def fill_signatures(self):
        seller = self.role == Role.SELLER
        assert (not seller and self.stage == Stage.INIT) or (
            seller and self.stage == Stage.SIGN), "Incorrect stage"

        # Public (total) excess
        pos = [
            self.commit, self.change_output.commit,
            self.secp.commit_value(self.fee_amount)
        ]
        neg = [x.commit for x in self.inputs]
        neg.append(self.secp.commit(0, self.offset))
        self.public_excess = self.secp.commit_sum(pos,
                                                  neg).to_public_key(self.secp)

        # Partial excess
        blind_sum = BlindSum()
        blind_sum.add_child_key(self.partial_child)
        if seller:
            blind_sum.add_child_key(self.change_child)
            for entry in self.input_entries:
                blind_sum.sub_child_key(self.wallet.derive_from_entry(entry))
            blind_sum.sub_blinding_factor(self.offset)
        excess = self.wallet.chain.blind_sum(blind_sum).to_secret_key(
            self.secp)

        # Partial signature
        public_nonce_sum = PublicKey.from_combination(
            self.secp, [self.public_nonce, self.foreign_public_nonce])
        self.partial_signature = aggsig.calculate_partial(
            self.secp, excess, self.nonce, self.public_excess,
            public_nonce_sum, self.fee_amount, self.lock_height)

        # First step of multi party bullet proof
        proof_builder = TwoPartyBulletProof(
            self.secp, self.partial_child.key,
            self.foreign_partial_commit.to_public_key(self.secp),
            self.grin_amount, self.commit)
        self.t_1, self.t_2 = proof_builder.round_1()

        if seller:
            proof_builder.fill_round_1(self.foreign_t_1, self.foreign_t_2)
            self.tau_x = proof_builder.round_2()

        # Public (total) refund excess
        pos = [
            self.refund_output.commit,
            self.secp.commit_value(self.refund_fee_amount)
        ]
        neg = [self.commit, self.secp.commit(0, self.refund_offset)]
        self.public_refund_excess = self.secp.commit_sum(
            pos, neg).to_public_key(self.secp)

        # Partial refund excess
        refund_blind_sum = BlindSum()
        refund_blind_sum.sub_child_key(self.partial_child)
        if seller:
            refund_blind_sum.add_child_key(self.refund_child)
            refund_blind_sum.sub_blinding_factor(self.refund_offset)
        refund_excess = self.wallet.chain.blind_sum(
            refund_blind_sum).to_secret_key(self.secp)

        # Partial refund signature
        public_refund_nonce_sum = PublicKey.from_combination(
            self.secp,
            [self.public_refund_nonce, self.foreign_public_refund_nonce])
        self.partial_refund_signature = aggsig.calculate_partial(
            self.secp, refund_excess, self.refund_nonce,
            self.public_refund_excess, public_refund_nonce_sum,
            self.refund_fee_amount, self.refund_lock_height)

    def finalize_range_proof(self):
        assert self.role == Role.BUYER and self.stage == Stage.SIGN, "Incorrect stage"

        proof_builder = TwoPartyBulletProof(
            self.secp, self.partial_child.key,
            self.foreign_partial_commit.to_public_key(self.secp),
            self.grin_amount, self.commit)
        proof_builder.fill_round_1(self.t_1, self.t_2)
        proof_builder.fill_round_1(self.foreign_t_1, self.foreign_t_2)
        proof_builder.round_2()
        proof_builder.fill_round_2(self.foreign_tau_x)
        self.range_proof = proof_builder.finalize()

    def build_transactions(self):
        assert self.role == Role.SELLER and self.stage == Stage.LOCK, "Incorrect stage"

        # Check output range proof
        output = Output(OutputFeatures.DEFAULT_OUTPUT, self.commit,
                        self.range_proof)
        assert output.verify(self.secp), "Invalid bulletproof"

        # Build refund tx
        refund_input = Input(OutputFeatures.DEFAULT_OUTPUT, self.commit)

        public_refund_nonce_sum = PublicKey.from_combination(
            self.secp,
            [self.public_refund_nonce, self.foreign_public_refund_nonce])

        refund_signature = aggsig.add_partials(self.secp, [
            self.partial_refund_signature,
            self.foreign_partial_refund_signature
        ], public_refund_nonce_sum)
        assert aggsig.verify(
            self.secp, refund_signature, self.public_refund_excess,
            self.refund_fee_amount,
            self.refund_lock_height), "Unable to verify refund signature"

        refund_kernel = Kernel(0, self.refund_fee_amount,
                               self.refund_lock_height, None, None)
        self.refund_tx = Transaction([refund_input], [self.refund_output],
                                     [refund_kernel], self.refund_offset)
        refund_kernel.excess = self.refund_tx.sum_commitments(self.secp)
        refund_kernel.excess_signature = refund_signature
        assert self.refund_tx.verify_kernels(
            self.secp), "Unable to verify refund kernel"

        # Build multisig tx
        public_nonce_sum = PublicKey.from_combination(
            self.secp, [self.public_nonce, self.foreign_public_nonce])

        signature = aggsig.add_partials(
            self.secp,
            [self.partial_signature, self.foreign_partial_signature],
            public_nonce_sum)
        assert aggsig.verify(self.secp, signature, self.public_excess, self.fee_amount, self.lock_height), \
            "Unable to verify signature"

        kernel = Kernel(0, self.fee_amount, self.lock_height, None, None)
        self.tx = Transaction(self.inputs, [self.change_output, output],
                              [kernel], self.offset)
        kernel.excess = self.tx.sum_commitments(self.secp)
        kernel.excess_signature = signature
        assert self.tx.verify_kernels(self.secp), "Unable to verify kernel"

        self.swap_nonce = SecretKey.random(self.secp)
        self.public_swap_nonce = self.swap_nonce.to_public_key(self.secp)

    def fill_swap_signatures(self):
        buyer = self.role == Role.BUYER
        assert (buyer and self.stage == Stage.LOCK) or (
            not buyer and self.stage == Stage.SWAP), "Incorrect stage"

        # Public (total) swap excess
        pos = [
            self.swap_output.commit,
            self.secp.commit_value(self.swap_fee_amount)
        ]
        neg = [self.commit, self.secp.commit(0, self.swap_offset)]
        self.public_swap_excess = self.secp.commit_sum(pos, neg).to_public_key(
            self.secp)

        # Partial swap excess
        swap_blind_sum = BlindSum()
        swap_blind_sum.sub_child_key(self.partial_child)
        if buyer:
            swap_blind_sum.add_child_key(self.swap_child)
            swap_blind_sum.sub_blinding_factor(self.swap_offset)
        swap_excess = self.wallet.chain.blind_sum(
            swap_blind_sum).to_secret_key(self.secp)

        # Nonce sum
        public_swap_nonce_sum = PublicKey.from_combination(
            self.secp,
            [self.public_swap_nonce, self.foreign_public_swap_nonce])

        if not buyer:
            # Verify that partial signature is valid with swap secret
            pos = [self.swap_output.commit]
            neg = [
                self.foreign_partial_commit,
                self.secp.commit(0, self.swap_offset),
                self.secp.commit_value(self.grin_amount - self.swap_fee_amount)
            ]
            foreign_public_partial_swap_excess = self.secp.commit_sum(
                pos, neg).to_public_key(self.secp)

            assert aggsig.verify_partial_adaptor(
                self.secp, self.foreign_partial_swap_adaptor,
                foreign_public_partial_swap_excess, self.public_lock,
                self.public_swap_excess, public_swap_nonce_sum,
                self.swap_fee_amount,
                self.swap_lock_height), "Partial swap signature not valid"

        # Partial swap signature
        self.partial_swap_signature = aggsig.calculate_partial(
            self.secp, swap_excess, self.swap_nonce, self.public_swap_excess,
            public_swap_nonce_sum, self.swap_fee_amount, self.swap_lock_height)

        if buyer:
            self.partial_swap_adaptor = aggsig.calculate_partial_adaptor(
                self.secp, swap_excess, self.swap_nonce, self.secret_lock,
                self.public_swap_excess, public_swap_nonce_sum,
                self.swap_fee_amount, self.swap_lock_height)

    def prepare_swap(self):
        assert self.role == Role.BUYER and self.stage == Stage.LOCK, "Incorrect stage"

        self.swap_nonce = SecretKey.random(self.secp)
        self.public_swap_nonce = self.swap_nonce.to_public_key(self.secp)
        self.swap_fee_amount = tx_fee(1, 1, MILLI_GRIN_UNIT)
        self.swap_lock_height = self.lock_height + 1
        self.swap_child, self.swap_entry = self.wallet.create_output(
            self.grin_amount - self.swap_fee_amount)
        self.wallet.save()
        self.swap_offset = BlindingFactor.from_secret_key(
            SecretKey.random(self.secp))
        self.swap_output = self.wallet.entry_to_output(self.swap_entry)

        self.fill_swap_signatures()

    def finalize_swap(self):
        seller = self.role == Role.SELLER
        assert (seller and self.stage == Stage.DONE) or (
            not seller and self.stage == Stage.SWAP), "Incorrect stage"

        if seller:
            self.secret_lock = self.foreign_partial_swap_adaptor.scalar(
                self.secp).add(
                    self.secp,
                    self.foreign_partial_swap_signature.scalar(
                        self.secp).negate(self.secp))

            public_lock = self.secret_lock.to_public_key(self.secp)
            assert self.public_lock == public_lock, "Invalid secret lock, this should never happen"

            if self.is_bitcoin_swap():
                tx = BitcoinTransaction(2, [], [], int(time()))
                input_script = self.generate_btc_script()
                for output_point in self.btc_output_points:
                    tx.add_input(
                        BitcoinInput(output_point.txid, output_point.index,
                                     input_script, bytearray(), None))
                output = BitcoinOutput(
                    1,
                    Script.p2(
                        Address.from_base58check(
                            self.swap_receive_address.encode())))
                tx.add_output(output)
                tx_size = len(tx.to_bytearray()) + 270 * len(
                    self.btc_output_points)  # estimate total tx size
                fee = 2 * tx_size  # 2 sat/B
                output.value = self.swap_amount - fee
                for i in range(len(tx.inputs)):
                    signature_a = tx.raw_signature(self.secp, i,
                                                   self.swap_cosign)
                    signature_b = tx.raw_signature(self.secp, i,
                                                   self.secret_lock)
                    prev_script = self.generate_btc_script()

                    script_sig = bytearray()
                    script_sig.append(OP_FALSE)
                    script_sig.extend(script_write_bytes(len(signature_a)))
                    script_sig.extend(signature_a)
                    script_sig.extend(script_write_bytes(len(signature_b)))
                    script_sig.extend(signature_b)
                    script_sig.append(OP_FALSE)
                    script_sig.extend(script_write_bytes(len(prev_script)))
                    script_sig.extend(prev_script)
                    tx.inputs[i].script_sig = script_sig
                self.claim = hexlify(tx.to_bytearray())

            if self.is_ether_swap():
                self.claim = self.secp.sign_recoverable(
                    self.secret_lock, bytearray([0] * 32))
        else:
            swap_input = Input(OutputFeatures.DEFAULT_OUTPUT, self.commit)
            public_swap_nonce_sum = PublicKey.from_combination(
                self.secp,
                [self.public_swap_nonce, self.foreign_public_swap_nonce])

            swap_signature = aggsig.add_partials(self.secp, [
                self.partial_swap_signature,
                self.foreign_partial_swap_signature
            ], public_swap_nonce_sum)

            assert aggsig.verify(
                self.secp, swap_signature, self.public_swap_excess,
                self.swap_fee_amount,
                self.swap_lock_height), "Unable to verify swap signature"

            swap_kernel = Kernel(0, self.swap_fee_amount,
                                 self.swap_lock_height, None, None)
            self.swap_tx = Transaction([swap_input], [self.swap_output],
                                       [swap_kernel], self.swap_offset)
            swap_kernel.excess = self.swap_tx.sum_commitments(self.secp)
            swap_kernel.excess_signature = swap_signature
            assert self.swap_tx.verify_kernels(
                self.secp), "Unable to verify swap kernel"

    def load(self, dct=None):
        seller = self.role == Role.SELLER
        buyer = not seller

        from_file = dct is None
        if from_file:
            f = open(absolute(self.swap_file), "r")
            dct = json.loads(f.read())
            f.close()

        self.stage = Stage(dct['stage'])
        if self.wallet is None:
            self.wallet = Wallet.open(self.secp, dct['wallet'])
        self.time_start = int(dct['time_start'])
        self.grin_amount = int(dct['grin_amount'])
        self.swap_currency = dct['swap_currency']
        self.swap_amount = int(dct['swap_amount'])
        if seller or self.is_ether_swap():
            self.swap_receive_address = dct['swap_receive_address']
        self.lock_height = int(dct['lock_height'])
        self.refund_lock_height = int(dct['refund_lock_height'])
        self.inputs = [
            Input.from_dict(self.secp, x, True) for x in dct['inputs']
        ]
        self.fee_amount = int(dct['fee_amount'])
        self.refund_fee_amount = int(dct['refund_fee_amount'])
        self.change_output = Output.from_dict(self.secp, dct['change_output'],
                                              True)
        if from_file:
            self.partial_entry = self.wallet.get_output(dct['partial_entry'])
            self.partial_child = self.wallet.derive_from_entry(
                self.partial_entry)
        self.partial_commit = self.wallet.commit_with_child_key(
            0, self.partial_child)
        self.offset = BlindingFactor.from_hex(dct['offset'].encode())
        self.refund_output = Output.from_dict(self.secp, dct['refund_output'],
                                              True)
        self.refund_offset = BlindingFactor.from_hex(
            dct['refund_offset'].encode())
        if from_file:
            self.nonce = SecretKey.from_hex(self.secp, dct['nonce'].encode())
            self.refund_nonce = SecretKey.from_hex(
                self.secp, dct['refund_nonce'].encode())
        self.public_nonce = self.nonce.to_public_key(self.secp)
        self.public_refund_nonce = self.refund_nonce.to_public_key(self.secp)

        if seller:
            if self.is_bitcoin_swap():
                self.swap_cosign = SecretKey.from_hex(
                    self.secp, dct['swap_cosign'].encode())
            self.input_entries = [
                self.wallet.get_output(x) for x in dct['input_entries']
            ]
            self.input_amount = sum(x.value for x in self.input_entries)
            self.change_amount = self.input_amount - self.grin_amount - self.fee_amount
            self.change_entry = self.wallet.get_output(dct['change_entry'])
            self.change_child = self.wallet.derive_from_entry(
                self.change_entry)
            self.refund_entry = self.wallet.get_output(dct['refund_entry'])
            self.refund_child = self.wallet.derive_from_entry(
                self.refund_entry)
        else:
            if from_file:
                self.secret_lock = SecretKey.from_hex(
                    self.secp, dct['secret_lock'].encode())
                if self.is_bitcoin_swap():
                    self.btc_refund_key = SecretKey.from_hex(
                        self.secp, dct['btc_refund_key'].encode())

        if self.is_bitcoin_swap():
            self.public_swap_cosign = self.swap_cosign.to_public_key(self.secp) if seller else \
                PublicKey.from_hex(self.secp, dct['public_swap_cosign'].encode())

        if self.stage >= Stage.SIGN or buyer:
            self.foreign_partial_commit = Commitment.from_hex(
                self.secp, dct['foreign_partial_commit'].encode())
            self.foreign_public_nonce = PublicKey.from_hex(
                self.secp, dct['foreign_public_nonce'].encode())
            self.foreign_public_refund_nonce = PublicKey.from_hex(
                self.secp, dct['foreign_public_refund_nonce'].encode())
            if from_file:
                self.public_lock = PublicKey.from_hex(
                    self.secp, dct['public_lock'].encode())
                if self.is_bitcoin_swap():
                    self.public_btc_refund_key = self.btc_refund_key.to_public_key(self.secp) if buyer else \
                        PublicKey.from_hex(self.secp, dct['public_btc_refund_key'].encode())

            if self.is_ether_swap():
                self.eth_address_lock = ethereum_address(
                    self.secp, self.public_lock).decode()

            self.commit = self.secp.commit_sum([self.foreign_partial_commit,
                                                self.wallet.commit(self.partial_entry)], []) if not from_file else \
                Commitment.from_hex(self.secp, dct['commit'].encode())

        if self.stage >= Stage.SIGN or (buyer and from_file):
            self.public_excess = PublicKey.from_hex(
                self.secp, dct['public_excess'].encode())
            self.public_refund_excess = PublicKey.from_hex(
                self.secp, dct['public_refund_excess'].encode())
            if self.is_bitcoin_swap():
                self.btc_lock_time = int(dct['btc_lock_time'])
                self.btc_lock_address = Address.from_base58check(
                    dct['btc_lock_address'].encode())
            if self.is_ether_swap():
                self.eth_contract_address = dct['eth_contract_address']
            self.partial_signature = Signature.from_hex(
                dct['partial_signature'].encode())
            self.partial_refund_signature = Signature.from_hex(
                dct['partial_refund_signature'].encode())
            self.t_1 = PublicKey.from_hex(self.secp, dct['t_1'].encode())
            self.t_2 = PublicKey.from_hex(self.secp, dct['t_2'].encode())

        if self.stage >= Stage.SIGN:
            self.foreign_t_1 = PublicKey.from_hex(self.secp,
                                                  dct['foreign_t_1'].encode())
            self.foreign_t_2 = PublicKey.from_hex(self.secp,
                                                  dct['foreign_t_2'].encode())
            if seller:
                self.tau_x = SecretKey.from_hex(self.secp,
                                                dct['tau_x'].encode())
                self.foreign_partial_signature = Signature.from_hex(
                    dct['foreign_partial_signature'].encode())
                self.foreign_partial_refund_signature = Signature.from_hex(
                    dct['foreign_partial_refund_signature'].encode())
                if self.is_bitcoin_swap():
                    self.btc_output_points = [
                        OutputPoint.from_hex(x.encode())
                        for x in dct['btc_output_points']
                    ]
            else:
                self.foreign_tau_x = SecretKey.from_hex(
                    self.secp, dct['foreign_tau_x'].encode())

        if self.stage >= Stage.LOCK or (self.stage == Stage.SIGN and buyer):
            self.range_proof = RangeProof.from_hex(dct['range_proof'].encode())

        if self.stage >= Stage.LOCK:
            self.tx_height = dct['tx_height']
            self.swap_nonce = SecretKey.from_hex(self.secp,
                                                 dct['swap_nonce'].encode())
            self.public_swap_nonce = self.swap_nonce.to_public_key(self.secp)
            if buyer:
                self.swap_entry = self.wallet.get_output(dct['swap_entry'])
                self.swap_child = self.wallet.derive_from_entry(
                    self.swap_entry)
                self.partial_swap_adaptor = Signature.from_hex(
                    dct['partial_swap_adaptor'].encode())

        if (buyer and self.stage >= Stage.LOCK) or (seller and
                                                    self.stage >= Stage.SWAP):
            self.foreign_public_swap_nonce = PublicKey.from_hex(
                self.secp, dct['foreign_public_swap_nonce'].encode())
            self.swap_fee_amount = int(dct['swap_fee_amount'])
            self.swap_lock_height = int(dct['swap_lock_height'])
            self.swap_output = Output.from_dict(self.secp, dct['swap_output'],
                                                True)
            self.swap_offset = BlindingFactor.from_hex(
                dct['swap_offset'].encode())
            self.public_swap_excess = PublicKey.from_hex(
                self.secp, dct['public_swap_excess'].encode())
            self.partial_swap_signature = Signature.from_hex(
                dct['partial_swap_signature'].encode())

        if seller and self.stage >= Stage.SWAP:
            self.foreign_partial_swap_adaptor = Signature.from_hex(
                dct['foreign_partial_swap_adaptor'].encode())

    def save(self):
        f = open(absolute(self.swap_file), "w")
        dct = self.to_dict(True)
        f.write(json.dumps(dct, indent=2))
        f.close()

    def to_dict(self, all: bool):
        seller = self.role == Role.SELLER
        buyer = not seller

        dct = {"id": str(self.id), "stage": self.stage.value}

        if all:
            dct.update({
                "wallet": self.wallet.dir_in,
                "time_start": self.time_start
            })
        else:
            dct.update(
                {"target": "buyer" if self.role == Role.SELLER else "seller"})

        if all or (self.stage == Stage.INIT and seller):
            dct.update({
                "grin_amount":
                self.grin_amount,
                "swap_currency":
                self.swap_currency,
                "swap_amount":
                self.swap_amount,
                "lock_height":
                self.lock_height,
                "refund_lock_height":
                self.refund_lock_height,
                "inputs": [x.to_dict(self.secp, True) for x in self.inputs],
                "fee_amount":
                self.fee_amount,
                "refund_fee_amount":
                self.refund_fee_amount,
                "change_output":
                self.change_output.to_dict(self.secp, True),
                "offset":
                self.offset.to_hex().decode(),
                "refund_output":
                self.refund_output.to_dict(self.secp, True),
                "refund_offset":
                self.refund_offset.to_hex().decode()
            })

            if (all and seller) or self.is_ether_swap():
                dct.update({
                    "swap_receive_address": self.swap_receive_address,
                })

        if not all and self.stage == Stage.INIT:
            dct.update({
                "partial_commit":
                self.partial_commit.to_hex(self.secp).decode(),
                "public_nonce":
                self.public_nonce.to_hex(self.secp).decode(),
                "public_refund_nonce":
                self.public_refund_nonce.to_hex(self.secp).decode()
            })

        if all:
            dct.update({
                "partial_entry":
                self.partial_entry.key_id.to_hex().decode(),
                "nonce":
                self.nonce.to_hex().decode(),
                "refund_nonce":
                self.refund_nonce.to_hex().decode()
            })
            if seller:
                dct.update({
                    "input_entries":
                    [x.key_id.to_hex().decode() for x in self.input_entries],
                    "change_entry":
                    self.change_entry.key_id.to_hex().decode(),
                    "refund_entry":
                    self.refund_entry.key_id.to_hex().decode()
                })
                if self.is_bitcoin_swap():
                    dct.update(
                        {"swap_cosign": self.swap_cosign.to_hex().decode()})
            else:
                dct.update({"secret_lock": self.secret_lock.to_hex().decode()})
                if self.is_bitcoin_swap():
                    dct.update({
                        "btc_refund_key":
                        self.btc_refund_key.to_hex().decode()
                    })

            if self.stage >= Stage.SIGN or buyer:
                dct.update({
                    "public_excess":
                    self.public_excess.to_hex(self.secp).decode(),
                    "public_refund_excess":
                    self.public_refund_excess.to_hex(self.secp).decode(),
                    "commit":
                    self.commit.to_hex(self.secp).decode(),
                    "foreign_partial_commit":
                    self.foreign_partial_commit.to_hex(self.secp).decode(),
                    "foreign_public_nonce":
                    self.foreign_public_nonce.to_hex(self.secp).decode(),
                    "foreign_public_refund_nonce":
                    self.foreign_public_refund_nonce.to_hex(
                        self.secp).decode()
                })
                if self.is_bitcoin_swap():
                    dct.update({
                        "btc_lock_address":
                        self.btc_lock_address.to_base58check().decode()
                    })

            if self.stage >= Stage.SIGN:
                if seller:
                    dct.update({
                        "foreign_partial_signature":
                        self.foreign_partial_signature.to_hex().decode(),
                        "foreign_partial_refund_signature":
                        self.foreign_partial_refund_signature.to_hex().decode(
                        )
                    })
                    if self.is_bitcoin_swap():
                        dct.update({
                            "btc_output_points": [
                                x.to_hex().decode()
                                for x in self.btc_output_points
                            ]
                        })
                else:
                    dct.update({
                        "foreign_tau_x":
                        self.foreign_tau_x.to_hex().decode()
                    })
                dct.update({
                    "foreign_t_1":
                    self.foreign_t_1.to_hex(self.secp).decode(),
                    "foreign_t_2":
                    self.foreign_t_2.to_hex(self.secp).decode()
                })

        if self.is_bitcoin_swap():
            if (all and buyer) or (not all and self.stage == Stage.INIT
                                   and seller):
                dct.update({
                    "public_swap_cosign":
                    self.public_swap_cosign.to_hex(self.secp).decode()
                })

            if (all and self.stage >= Stage.SIGN
                    and seller) or (not all and self.stage == Stage.INIT
                                    and buyer):
                dct.update({
                    "public_btc_refund_key":
                    self.public_btc_refund_key.to_hex(self.secp).decode(),
                })

        if (all and
            (self.stage >= Stage.SIGN or buyer)) or (self.stage == Stage.INIT
                                                     and buyer):
            dct.update({
                "public_lock":
                self.public_lock.to_hex(self.secp).decode(),
                "partial_signature":
                self.partial_signature.to_hex().decode(),
                "partial_refund_signature":
                self.partial_refund_signature.to_hex().decode()
            })

            if self.is_bitcoin_swap():
                dct.update({"btc_lock_time": self.btc_lock_time})
            if self.is_ether_swap():
                dct.update({"eth_contract_address": self.eth_contract_address})

        if (all and (self.stage >= Stage.SIGN or buyer)) or (self.stage == Stage.INIT and buyer) or \
                (self.stage == Stage.SIGN and seller):
            dct.update({
                "t_1": self.t_1.to_hex(self.secp).decode(),
                "t_2": self.t_2.to_hex(self.secp).decode()
            })

        if seller and ((all and self.stage >= Stage.SIGN)
                       or self.stage == Stage.SIGN):
            dct.update({"tau_x": self.tau_x.to_hex().decode()})

        if (all and ((self.stage >= Stage.SIGN and buyer) or (self.stage >= Stage.LOCK and seller))) or \
                (self.stage == Stage.SIGN and buyer):
            dct.update({"range_proof": self.range_proof.to_hex().decode()})

        if (all and self.stage >= Stage.LOCK) or (self.stage == Stage.LOCK
                                                  and seller):
            dct.update({"tx_height": self.tx_height})

        if all and self.stage >= Stage.LOCK:
            dct.update({"swap_nonce": self.swap_nonce.to_hex().decode()})

        if (all and self.stage >= Stage.LOCK) or self.stage == Stage.LOCK:
            dct.update({
                "public_swap_nonce":
                self.public_swap_nonce.to_hex(self.secp).decode()
            })

        if all and ((self.stage >= Stage.LOCK and buyer) or
                    (self.stage >= Stage.SWAP and seller)):
            dct.update({
                "foreign_public_swap_nonce":
                self.foreign_public_swap_nonce.to_hex(self.secp).decode(),
                "public_swap_excess":
                self.public_swap_excess.to_hex(self.secp).decode(),
            })

        if all and self.stage >= Stage.LOCK and buyer:
            dct.update(
                {"swap_entry": self.swap_entry.key_id.to_hex().decode()})

        if (all and ((self.stage >= Stage.LOCK and buyer) or (self.stage >= Stage.SWAP and seller))) or \
                (self.stage == Stage.LOCK and buyer):
            dct.update({
                "swap_fee_amount": self.swap_fee_amount,
                "swap_lock_height": self.swap_lock_height,
                "swap_output": self.swap_output.to_dict(self.secp, True),
                "swap_offset": self.swap_offset.to_hex().decode()
            })

        if buyer and ((all and self.stage >= Stage.LOCK)
                      or self.stage == Stage.LOCK):
            dct.update({
                "partial_swap_adaptor":
                self.partial_swap_adaptor.to_hex().decode()
            })

        if all and self.stage >= Stage.SWAP and seller:
            dct.update({
                "foreign_partial_swap_adaptor":
                self.foreign_partial_swap_adaptor.to_hex().decode()
            })

        if (all and ((self.stage >= Stage.LOCK and buyer) or (self.stage >= Stage.SWAP and seller))) or \
                self.stage == Stage.SWAP:
            dct.update({
                "partial_swap_signature":
                self.partial_swap_signature.to_hex().decode()
            })

        if all and ((self.stage >= Stage.SWAP and buyer) or
                    (self.stage >= Stage.DONE and seller)):
            dct.update({
                "foreign_partial_swap_signature":
                self.foreign_partial_swap_signature.to_hex().decode()
            })

        return dct

    def receive(self, dct: dict):
        if self.stage is None:
            if self.role == Role.BUYER:
                dct['time_start'] = int(time())

                self.wallet = Wallet.open(self.secp, dct['wallet'])

                # Add 'foreign_' prefix to some keys
                dct.update({
                    "foreign_partial_commit":
                    dct['partial_commit'],
                    "foreign_public_nonce":
                    dct['public_nonce'],
                    "foreign_public_refund_nonce":
                    dct['public_refund_nonce']
                })

                dct.pop("partial_commit", None)
                dct.pop("public_nonce", None)
                dct.pop("public_refund_nonce", None)

                # Partial multisig output
                self.partial_child, self.partial_entry = self.wallet.create_output(
                    dct['grin_amount'])
                self.partial_entry.mark_locked()

                self.nonce = SecretKey.random(self.secp)
                self.refund_nonce = SecretKey.random(self.secp)

                self.secret_lock = SecretKey.random(self.secp)
                self.public_lock = self.secret_lock.to_public_key(self.secp)

                if dct['swap_currency'] == "BTC":
                    self.btc_lock_time = int(time() + 24 * 60 * 60)
                    self.btc_refund_key = SecretKey.random(self.secp)
                    self.public_btc_refund_key = self.btc_refund_key.to_public_key(
                        self.secp)

                self.load(dct)
                if self.is_bitcoin_swap():
                    self.btc_lock_address = self.calculate_btc_lock_address()
                self.wallet.save()
            else:
                raise Exception("This stage doesn't expect an input file")
        elif self.stage == Stage.INIT:
            self.stage = Stage.SIGN
            self.foreign_t_1 = PublicKey.from_hex(self.secp,
                                                  dct['t_1'].encode())
            self.foreign_t_2 = PublicKey.from_hex(self.secp,
                                                  dct['t_2'].encode())
            if self.role == Role.SELLER:
                self.foreign_partial_commit = Commitment.from_hex(
                    self.secp, dct['partial_commit'].encode())
                self.foreign_public_nonce = PublicKey.from_hex(
                    self.secp, dct['public_nonce'].encode())
                self.foreign_public_refund_nonce = PublicKey.from_hex(
                    self.secp, dct['public_refund_nonce'].encode())
                self.public_lock = PublicKey.from_hex(
                    self.secp, dct['public_lock'].encode())
                if self.is_bitcoin_swap():
                    self.btc_lock_time = int(dct['btc_lock_time'])
                    self.public_btc_refund_key = PublicKey.from_hex(
                        self.secp, dct['public_btc_refund_key'])
                    self.btc_lock_address = self.calculate_btc_lock_address()
                if self.is_ether_swap():
                    self.eth_address_lock = ethereum_address(
                        self.secp, self.public_lock).decode()
                    self.eth_contract_address = dct['eth_contract_address']
                self.commit = self.secp.commit_sum([
                    self.foreign_partial_commit,
                    self.wallet.commit(self.partial_entry)
                ], [])
                self.foreign_partial_signature = Signature.from_hex(
                    dct['partial_signature'].encode())
                self.foreign_partial_refund_signature = Signature.from_hex(
                    dct['partial_refund_signature'].encode())
            else:
                self.foreign_tau_x = SecretKey.from_hex(
                    self.secp, dct['tau_x'].encode())
        elif self.stage == Stage.SIGN:
            self.stage = Stage.LOCK
            if self.role == Role.SELLER:
                self.range_proof = RangeProof.from_hex(
                    dct['range_proof'].encode())
            else:
                self.tx_height = dct['tx_height']
                self.foreign_public_swap_nonce = PublicKey.from_hex(
                    self.secp, dct['public_swap_nonce'].encode())
        elif self.stage == Stage.LOCK:
            self.stage = Stage.SWAP
            if self.role == Role.SELLER:
                self.foreign_public_swap_nonce = PublicKey.from_hex(
                    self.secp, dct['public_swap_nonce'].encode())
                self.swap_fee_amount = int(dct['swap_fee_amount'])
                self.swap_lock_height = int(dct['swap_lock_height'])
                self.swap_output = Output.from_dict(self.secp,
                                                    dct['swap_output'], True)
                self.swap_offset = BlindingFactor.from_hex(
                    dct['swap_offset'].encode())
                self.foreign_partial_swap_adaptor = Signature.from_hex(
                    dct['partial_swap_adaptor'])
            else:
                self.foreign_partial_swap_signature = Signature.from_hex(
                    dct['partial_swap_signature'])
        elif self.stage == Stage.SWAP:
            self.stage = Stage.DONE
            if self.role == Role.SELLER:
                self.foreign_partial_swap_signature = Signature.from_hex(
                    dct['partial_swap_signature'])
        else:
            raise Exception("Invalid stage")

    def send(self) -> dict:
        return self.to_dict(False)

    def short_id(self) -> str:
        return str(self.id)[:8]

    def generate_btc_script(self) -> bytearray:
        assert self.is_bitcoin_swap()
        return Script.multisig_refund(self.secp, self.public_swap_cosign,
                                      self.public_lock,
                                      self.public_btc_refund_key,
                                      self.btc_lock_time)

    def calculate_btc_lock_address(self) -> Address:
        return Address.from_script(self.generate_btc_script(), False)
Esempio n. 7
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    def finalize_swap(self):
        seller = self.role == Role.SELLER
        assert (seller and self.stage == Stage.DONE) or (
            not seller and self.stage == Stage.SWAP), "Incorrect stage"

        if seller:
            self.secret_lock = self.foreign_partial_swap_adaptor.scalar(
                self.secp).add(
                    self.secp,
                    self.foreign_partial_swap_signature.scalar(
                        self.secp).negate(self.secp))

            public_lock = self.secret_lock.to_public_key(self.secp)
            assert self.public_lock == public_lock, "Invalid secret lock, this should never happen"

            if self.is_bitcoin_swap():
                tx = BitcoinTransaction(2, [], [], int(time()))
                input_script = self.generate_btc_script()
                for output_point in self.btc_output_points:
                    tx.add_input(
                        BitcoinInput(output_point.txid, output_point.index,
                                     input_script, bytearray(), None))
                output = BitcoinOutput(
                    1,
                    Script.p2(
                        Address.from_base58check(
                            self.swap_receive_address.encode())))
                tx.add_output(output)
                tx_size = len(tx.to_bytearray()) + 270 * len(
                    self.btc_output_points)  # estimate total tx size
                fee = 2 * tx_size  # 2 sat/B
                output.value = self.swap_amount - fee
                for i in range(len(tx.inputs)):
                    signature_a = tx.raw_signature(self.secp, i,
                                                   self.swap_cosign)
                    signature_b = tx.raw_signature(self.secp, i,
                                                   self.secret_lock)
                    prev_script = self.generate_btc_script()

                    script_sig = bytearray()
                    script_sig.append(OP_FALSE)
                    script_sig.extend(script_write_bytes(len(signature_a)))
                    script_sig.extend(signature_a)
                    script_sig.extend(script_write_bytes(len(signature_b)))
                    script_sig.extend(signature_b)
                    script_sig.append(OP_FALSE)
                    script_sig.extend(script_write_bytes(len(prev_script)))
                    script_sig.extend(prev_script)
                    tx.inputs[i].script_sig = script_sig
                self.claim = hexlify(tx.to_bytearray())

            if self.is_ether_swap():
                self.claim = self.secp.sign_recoverable(
                    self.secret_lock, bytearray([0] * 32))
        else:
            swap_input = Input(OutputFeatures.DEFAULT_OUTPUT, self.commit)
            public_swap_nonce_sum = PublicKey.from_combination(
                self.secp,
                [self.public_swap_nonce, self.foreign_public_swap_nonce])

            swap_signature = aggsig.add_partials(self.secp, [
                self.partial_swap_signature,
                self.foreign_partial_swap_signature
            ], public_swap_nonce_sum)

            assert aggsig.verify(
                self.secp, swap_signature, self.public_swap_excess,
                self.swap_fee_amount,
                self.swap_lock_height), "Unable to verify swap signature"

            swap_kernel = Kernel(0, self.swap_fee_amount,
                                 self.swap_lock_height, None, None)
            self.swap_tx = Transaction([swap_input], [self.swap_output],
                                       [swap_kernel], self.swap_offset)
            swap_kernel.excess = self.swap_tx.sum_commitments(self.secp)
            swap_kernel.excess_signature = swap_signature
            assert self.swap_tx.verify_kernels(
                self.secp), "Unable to verify swap kernel"