[Prototype/Do-not-Merge] Add NonWitness UTXO in PSBT

[jmacato]

DO NOT MERGE since this is only to verify if the solution works

This is a prototype for resolving the Trezor hardware wallet issue.

Depends on MetacoSA/NBitcoin#873
Depends on bitcoin-core/HWI#340
Contributes to #3734

[yahiheb]

This is the psbt when building a transaction

{
  "fee": "0.00000110 BTC",
  "feeRate": "1 Sat/B",
  "tx": {
    "hash": "a4d55d78b55376636a59bfa07a9978070c9f071a09445567990f459363fdeb5c",
    "ver": 1,
    "vin_sz": 1,
    "vout_sz": 1,
    "lock_time": 0,
    "size": 82,
    "in": [
      {
        "prev_out": {
          "hash": "89600973f98c7fba0443ab785cbde2ba94b0b90ce0d8039b8c58d8cd9e7d221a",
          "n": 0
        },
        "scriptSig": ""
      }
    ],
    "out": [
      {
        "value": "0.00099890",
        "scriptPubKey": "0 5353cb751a8616e6f7a9b584f63b612d2dc023af"
      }
    ]
  },
  "inputs": [
    {
      "index": 0,
      "partial_signatures": {},
      "non_witness_utxo": {
        "hash": "89600973f98c7fba0443ab785cbde2ba94b0b90ce0d8039b8c58d8cd9e7d221a",
        "ver": 2,
        "vin_sz": 1,
        "vout_sz": 2,
        "lock_time": 1772273,
        "size": 136,
        "in": [
          {
            "prev_out": {
              "hash": "cdc92401e1b23bd72d412a0dc26f1b13d3f977369a36610312e03c4562959c7e",
              "n": 1
            },
            "scriptSig": "0014148cdae5ffcf48bcef27d7f6222f8af2a976b573",
            "sequence": 4294967294
          }
        ],
        "out": [
          {
            "value": "0.00100000",
            "scriptPubKey": "0 51a1379ddea95aa5a77e00ecc12fe64ec0aa6ab0"
          },
          {
            "value": "0.01851315",
            "scriptPubKey": "0 b0f031e5cddf1befd1428bc305af6c7c2840a357"
          }
        ]
      },
      "witness_utxo": {
        "value": "0.00100000",
        "scriptPubKey": "0 51a1379ddea95aa5a77e00ecc12fe64ec0aa6ab0"
      },
      "bip32_derivs": [
        {
          "pubkey": "0325ccb1f60a3d0640cbc3bfa1cefc34512d50c32d0e7c102b62e18f23ab69fbc5",
          "master_fingerprint": "e5dbc9cb",
          "path": "84'/0'/0'/0/0"
        }
      ]
    }
  ],
  "outputs": [
    {
      "bip32_derivs": [
        {
          "pubkey": "033e76da92a86af2436ad8c77222df038097189d64de79a64d329577b6c8305279",
          "master_fingerprint": "e5dbc9cb",
          "path": "84'/0'/0'/0/2"
        }
      ]
    }
  ]
}

[yahiheb]

there is this error when signing:

2020-06-19 05:24:39 ERROR       SendControlViewModel (361)      WalletWasabi.Hwi.Exceptions.HwiException: PSBT is not sane
   at WalletWasabi.Hwi.HwiClient.ThrowIfError(String responseString, IEnumerable`1 options) in C:\Users\HOME\Desktop\WalletWasabi - Copie\WalletWasabi\Hwi\HwiClient.cs:line 271
   at WalletWasabi.Hwi.HwiClient.SendCommandAsync(IEnumerable`1 options, Nullable`1 command, String commandArguments, Boolean openConsole, CancellationToken cancel, Boolean isRecursion) in C:\Users\HOME\Desktop\WalletWasabi - Copie\WalletWasabi\Hwi\HwiClient.cs:line 57
   at WalletWasabi.Hwi.HwiClient.SignTxImplAsync(Nullable`1 deviceType, String devicePath, Nullable`1 fingerprint, PSBT psbt, CancellationToken cancel) in C:\Users\HOME\Desktop\WalletWasabi - Copie\WalletWasabi\Hwi\HwiClient.cs:line 175
   at WalletWasabi.Hwi.HwiClient.SignTxAsync(HDFingerprint fingerprint, PSBT psbt, CancellationToken cancel) in C:\Users\HOME\Desktop\WalletWasabi - Copie\WalletWasabi\Hwi\HwiClient.cs:line 169
   at WalletWasabi.Gui.Controls.WalletExplorer.SendTabViewModel.BuildTransaction(String password, PaymentIntent payments, FeeStrategy feeStrategy, Boolean allowUnconfirmed, IEnumerable`1 allowedInputs) in C:\Users\HOME\Desktop\WalletWasabi - Copie\WalletWasabi.Gui\Controls\WalletExplorer\SendTabViewModel.cs:line 60
   at WalletWasabi.Gui.Controls.WalletExplorer.SendControlViewModel.<.ctor>b__28_29() in C:\Users\HOME\Desktop\WalletWasabi - Copie\WalletWasabi.Gui\Controls\WalletExplorer\SendControlViewModel.cs:line 346

[yahiheb]

The test was done using the HWI that comes within Wasabi

[molnard]

Concept ACK. What BitcoinStore do if the tx is not there?

[jmacato]

@molnard it returns false, which skips the input's non segwit field. We can do a warning of some kind if it does that

[lontivero]

If the transaction is not in the TransactionStore then we are trying to spend a coin that is not ours. That can happen only in coinjoin transactions (wasabi coinjoin and payjoin) in nonde of those cases Trezor (or any other HW at the moment) can be used.

[molnard]

So we should not support PayJoin with Hardware wallets?

[lontivero]

@jmacato please make this PR reviewable.

• NBitcoin 5.0.43 was already released with your chnages. Update it here on in other PR and remove the submodule.
• Update the transactions in the UpdatePSBTInfo method. That is the method where all the additional info is added.
• I see HWI binaries for Linux and Windows only. Where is the one for macos?

IMO all these should be done in separate PRs because we need them independently of this specific PR.

[jmacato]

@lontivero yes but to reiterate again: this PR is only for prototyping and i don't recommend reviewing this. I'll be posting series of PR's for this issue tomorrow.

[lontivero]

So we should not support PayJoin with Hardware wallets?

Trezor requires the inclusion of the transactions that create each coin that is being spent and in payjoin we don't have the transaction for the coin added by the receiver so, given we don't have the required info Trezor will refuse to sign that payjoin transaction.

Note: the receiver could include that transaction in the psbt that he responds with but that requires a change in the bip78 (that bip is being discussed right now so, we could suggest this)

[jmacato]

also i didnt made any macOS build of HWI since docker doesnt support them (and i dont have mac too...) we need to have a new release from HWI

[lontivero]

I see. What are we going to do with these binaries? I think we have to wait for the official release. @achow101, what is the plan? are you going to release a new version of HWI containing the change for Trezor only or that is just one of many other changes that will be included in a much bigger release version?

[yahiheb]

There is a release candidate bitcoin-core/HWI#340 (comment)

[yahiheb]

#3822 is merged so closing this.