Refactor common data structure for wallet into SigningContext

BTCPayServer.Tests/PSBTTests.cs

@@ -67,8 +67,8 @@ namespace BTCPayServer.Tests
                     CurrentBalance = 1.5m
                 };
                 var vmLedger = await walletController.WalletSend(walletId, sendModel, command: "ledger").AssertViewModelAsync<WalletSendLedgerModel>();
-                PSBT.Parse(vmLedger.PSBT, user.SupportedNetwork.NBitcoinNetwork);
+                PSBT.Parse(vmLedger.SigningContext.PSBT, user.SupportedNetwork.NBitcoinNetwork);
-                BitcoinAddress.Create(vmLedger.HintChange, user.SupportedNetwork.NBitcoinNetwork);
+                BitcoinAddress.Create(vmLedger.SigningContext.ChangeAddress, user.SupportedNetwork.NBitcoinNetwork);
                 Assert.NotNull(vmLedger.WebsocketPath);
 
                 string redirectedPSBT = AssertRedirectedPSBT(await walletController.WalletSend(walletId, sendModel, command: "analyze-psbt"), nameof(walletController.WalletPSBT));
@@ -82,17 +82,23 @@ namespace BTCPayServer.Tests
                 await walletController.WalletPSBT(walletId, vmPSBT, "ledger").AssertViewModelAsync<WalletSendLedgerModel>();
                 var vmPSBT2 = await walletController.WalletPSBTReady(walletId, new WalletPSBTReadyViewModel()
                 {
-                    PSBT = AssertRedirectedPSBT( await walletController.WalletPSBT(walletId, vmPSBT, "broadcast"), nameof(walletController.WalletPSBTReady))
+                    SigningContext = new SigningContextModel()
+                    {
+                        PSBT = AssertRedirectedPSBT( await walletController.WalletPSBT(walletId, vmPSBT, "broadcast"), nameof(walletController.WalletPSBTReady))
+                    }
                 } ).AssertViewModelAsync<WalletPSBTReadyViewModel>();
                 Assert.NotEmpty(vmPSBT2.Inputs.Where(i => i.Error != null));
-                Assert.Equal(vmPSBT.PSBT, vmPSBT2.PSBT);
+                Assert.Equal(vmPSBT.PSBT, vmPSBT2.SigningContext.PSBT);
 
                 var signedPSBT = unsignedPSBT.Clone();
                 signedPSBT.SignAll(user.DerivationScheme, user.GenerateWalletResponseV.AccountHDKey, user.GenerateWalletResponseV.AccountKeyPath);
                 vmPSBT.PSBT = signedPSBT.ToBase64();
                 var psbtReady = await walletController.WalletPSBTReady(walletId, new WalletPSBTReadyViewModel()
                 {
-                    PSBT = AssertRedirectedPSBT( await walletController.WalletPSBT(walletId, vmPSBT, "broadcast"), nameof(walletController.WalletPSBTReady))
+                    SigningContext = new SigningContextModel()
+                    {
+                        PSBT = AssertRedirectedPSBT(await walletController.WalletPSBT(walletId, vmPSBT, "broadcast"), nameof(walletController.WalletPSBTReady))
+                    }
                 } ).AssertViewModelAsync<WalletPSBTReadyViewModel>();
                 Assert.Equal(2 + 1, psbtReady.Destinations.Count); // The fee is a destination
                 Assert.Contains(psbtReady.Destinations, d => d.Destination == sendDestination && !d.Positive);
@@ -122,9 +128,12 @@ namespace BTCPayServer.Tests
 
                 var ready = (await walletController.WalletPSBTReady(walletId, new WalletPSBTReadyViewModel()
                 {
-                    PSBT = signedPSBT.ToBase64()
+                    SigningContext = new SigningContextModel()
+                    {
+                        PSBT = signedPSBT.ToBase64()
+                    }
                 })).AssertViewModel<WalletPSBTReadyViewModel>();
-                Assert.Equal(signedPSBT.ToBase64(), ready.PSBT);
+                Assert.Equal(signedPSBT.ToBase64(), ready.SigningContext.PSBT);
                 psbt = AssertRedirectedPSBT(await walletController.WalletPSBTReady(walletId, ready, command: "analyze-psbt"), nameof(walletController.WalletPSBT));
                 Assert.Equal(signedPSBT.ToBase64(), psbt);
                 redirect = Assert.IsType<RedirectToActionResult>(await walletController.WalletPSBTReady(walletId, ready, command: "broadcast"));

BTCPayServer/BTCPayServer.csproj

@@ -2,8 +2,8 @@
   <Import Project="../Build/Version.csproj" Condition="Exists('../Build/Version.csproj')" />
   <Import Project="../Build/Common.csproj" />
   <PropertyGroup Condition="'$(Configuration)' == 'Debug' And '$(RazorCompileOnBuild)' != 'true'">
-    <!--<RazorCompileOnBuild>false</RazorCompileOnBuild>
+    <RazorCompileOnBuild>false</RazorCompileOnBuild>
-    <DefineConstants>$(DefineConstants);RAZOR_RUNTIME_COMPILE</DefineConstants>-->
+    <DefineConstants>$(DefineConstants);RAZOR_RUNTIME_COMPILE</DefineConstants>
   </PropertyGroup>
   <PropertyGroup>
     <OutputType>Exe</OutputType>
@@ -187,6 +187,9 @@
 	  <Content Update="Views\Wallets\ListWallets.cshtml">
 	    <Pack>$(IncludeRazorContentInPack)</Pack>
 	  </Content>
+	  <Content Update="Views\Wallets\WalletPSBT - Copy.cshtml">
+	    <Pack>$(IncludeRazorContentInPack)</Pack>
+	  </Content>
 	  <Content Update="Views\Wallets\WalletPSBTCombine.cshtml">
 	    <Pack>$(IncludeRazorContentInPack)</Pack>
 	  </Content>

BTCPayServer/Controllers/WalletsController.PSBT.cs

@@ -101,7 +101,7 @@ namespace BTCPayServer.Controllers
                 return View(vm);
             }
 
-            var res = await TryHandleSigningCommands(walletId, psbt, command, vm.SigningContext, null);
+            var res = await TryHandleSigningCommands(walletId, psbt, command, vm.SigningContext);
             if (res != null)
             {
                 return res;
@@ -137,7 +137,10 @@ namespace BTCPayServer.Controllers
                 {
                     return RedirectToWalletPSBTReady(new WalletPSBTReadyViewModel()
                     {
-                        PSBT = psbt.ToBase64()
+                        SigningContext = new SigningContextModel()
+                        {
+                            PSBT = psbt.ToBase64()
+                        }
                     });
                 }
                 case "combine":
@@ -183,7 +186,7 @@ namespace BTCPayServer.Controllers
 
         private async Task FetchTransactionDetails(DerivationSchemeSettings derivationSchemeSettings, WalletPSBTReadyViewModel vm, BTCPayNetwork network)
         {
-            var psbtObject = PSBT.Parse(vm.PSBT, network.NBitcoinNetwork);
+            var psbtObject = PSBT.Parse(vm.SigningContext.PSBT, network.NBitcoinNetwork);
             if (!psbtObject.IsAllFinalized())
                 psbtObject = await ExplorerClientProvider.UpdatePSBT(derivationSchemeSettings, psbtObject) ?? psbtObject;
             IHDKey signingKey = null;
@@ -296,7 +299,7 @@ namespace BTCPayServer.Controllers
             DerivationSchemeSettings derivationSchemeSettings = null;
             try
             {
-                psbt = PSBT.Parse(vm.PSBT, network.NBitcoinNetwork);
+                psbt = PSBT.Parse(vm.SigningContext.PSBT, network.NBitcoinNetwork);
                 derivationSchemeSettings = GetDerivationSchemeSettings(walletId);
                 if (derivationSchemeSettings == null)
                     return NotFound();
@@ -322,8 +325,8 @@ namespace BTCPayServer.Controllers
                             proposedPayjoin = proposedPayjoin.SignAll(derivationSchemeSettings.AccountDerivation,
                                 extKey,
                                 RootedKeyPath.Parse(vm.SigningKeyPath));
-                            vm.PSBT = proposedPayjoin.ToBase64();
+                            vm.SigningContext.PSBT = proposedPayjoin.ToBase64();
-                            vm.OriginalPSBT = psbt.ToBase64();
+                            vm.SigningContext.OriginalPSBT = psbt.ToBase64();
                             proposedPayjoin.Finalize();
                             var hash = proposedPayjoin.ExtractTransaction().GetHash();
                             _EventAggregator.Publish(new UpdateTransactionLabel()
@@ -359,7 +362,9 @@ namespace BTCPayServer.Controllers
                                     $"The amount being sent may appear higher but is in fact almost same.<br/><br/>" +
                                     $"If you cancel or refuse to sign this transaction, the payment will proceed without payjoin"
                             });
-                            return ViewVault(walletId, proposedPayjoin, vm.SigningContext, psbt);
+                            vm.SigningContext.PSBT = proposedPayjoin.ToBase64();
+                            vm.SigningContext.OriginalPSBT = psbt.ToBase64();
+                            return ViewVault(walletId, vm.SigningContext);
                         }
                     }
                     catch (PayjoinReceiverException ex)
@@ -397,7 +402,7 @@ namespace BTCPayServer.Controllers
                         var broadcastResult = await ExplorerClientProvider.GetExplorerClient(network).BroadcastAsync(transaction);
                         if (!broadcastResult.Success)
                         {
-                            if (!string.IsNullOrEmpty(vm.OriginalPSBT))
+                            if (!string.IsNullOrEmpty(vm.SigningContext.OriginalPSBT))
                             {
                                 TempData.SetStatusMessageModel(new StatusMessageModel()
                                 {
@@ -405,8 +410,8 @@ namespace BTCPayServer.Controllers
                                     AllowDismiss = false,
                                     Html = $"The payjoin transaction could not be broadcasted.<br/>({broadcastResult.RPCCode} {broadcastResult.RPCCodeMessage} {broadcastResult.RPCMessage}).<br/>The transaction has been reverted back to its original format and has been broadcast."
                                 });
-                                vm.PSBT = vm.OriginalPSBT;
+                                vm.SigningContext.PSBT = vm.SigningContext.OriginalPSBT;
-                                vm.OriginalPSBT = null;
+                                vm.SigningContext.OriginalPSBT = null;
                                 return await WalletPSBTReady(walletId, vm, "broadcast");
                             }
                         
@@ -470,16 +475,17 @@ namespace BTCPayServer.Controllers
         }
 
         private async Task<IActionResult> TryHandleSigningCommands(WalletId walletId, PSBT psbt, string command,
-            SigningContextModel signingContext, BitcoinAddress changeAddress)
+            SigningContextModel signingContext)
         {
+            signingContext.PSBT = psbt.ToBase64();
             switch (command )
             {
                 case "vault":
-                    return ViewVault(walletId, psbt, signingContext);
+                    return ViewVault(walletId, signingContext);
                 case "ledger":
-                    return ViewWalletSendLedger(walletId, psbt, changeAddress);
+                    return ViewWalletSendLedger(walletId, signingContext);
                 case "seed":
-                    return SignWithSeed(walletId, psbt.ToBase64(), signingContext);
+                    return SignWithSeed(walletId, signingContext);
                 case "nbx-seed":
                     if (await CanUseHotWallet())
                     {
@@ -487,9 +493,8 @@ namespace BTCPayServer.Controllers
                         var extKey = await ExplorerClientProvider.GetExplorerClient(walletId.CryptoCode)
                             .GetMetadataAsync<string>(derivationScheme.AccountDerivation,
                                 WellknownMetadataKeys.MasterHDKey);
-
                         return SignWithSeed(walletId,
-                            new SignWithSeedViewModel() {SeedOrKey = extKey, PSBT = psbt.ToBase64(), SigningContext = signingContext });
+                            new SignWithSeedViewModel() {SeedOrKey = extKey, SigningContext = signingContext });
                     }
                     TempData.SetStatusMessageModel(new StatusMessageModel()
                     {

BTCPayServer/Controllers/WalletsController.cs

@@ -97,7 +97,7 @@ namespace BTCPayServer.Controllers
         }
 
         // Borrowed from https://github.com/ManageIQ/guides/blob/master/labels.md
-        string[] LabelColorScheme = new string[] 
+        string[] LabelColorScheme = new string[]
         {
             "#fbca04",
             "#0e8a16",
@@ -117,10 +117,10 @@ namespace BTCPayServer.Controllers
             // addlabelclick is if the user click on existing label. For some reason, reusing the same name attribute for both
             // does not work
             [ModelBinder(typeof(WalletIdModelBinder))]
-            WalletId walletId, string transactionId, 
+            WalletId walletId, string transactionId,
-                                string addlabel = null, 
+                                string addlabel = null,
                                 string addlabelclick = null,
-                                string addcomment = null, 
+                                string addcomment = null,
                                 string removelabel = null)
         {
             addlabel = addlabel ?? addlabelclick;
@@ -135,7 +135,7 @@ namespace BTCPayServer.Controllers
             }
             catch { }
             /////////
-            
+
             DerivationSchemeSettings paymentMethod = GetDerivationSchemeSettings(walletId);
             if (paymentMethod == null)
                 return NotFound();
@@ -147,7 +147,7 @@ namespace BTCPayServer.Controllers
             var walletTransactionsInfo = await walletTransactionsInfoAsync;
             if (addlabel != null)
             {
-                addlabel = addlabel.Trim().TrimStart('{').ToLowerInvariant().Replace(',',' ').Truncate(MaxLabelSize);
+                addlabel = addlabel.Trim().TrimStart('{').ToLowerInvariant().Replace(',', ' ').Truncate(MaxLabelSize);
                 var labels = _labelFactory.GetLabels(walletBlobInfo, Request);
                 if (!walletTransactionsInfo.TryGetValue(transactionId, out var walletTransactionInfo))
                 {
@@ -290,7 +290,7 @@ namespace BTCPayServer.Controllers
 
                     if (walletTransactionsInfo.TryGetValue(tx.TransactionId.ToString(), out var transactionInfo))
                     {
-                        var labels =  _labelFactory.GetLabels(walletBlob, transactionInfo, Request);
+                        var labels = _labelFactory.GetLabels(walletBlob, transactionInfo, Request);
                         vm.Labels.AddRange(labels);
                         model.Labels.AddRange(labels);
                         vm.Comment = transactionInfo.Comment;
@@ -359,7 +359,7 @@ namespace BTCPayServer.Controllers
                     }
                     var address = cachedAddress.ScriptPubKey.GetDestinationAddress(network.NBitcoinNetwork);
                     ExplorerClientProvider.GetExplorerClient(network)
-                        .CancelReservation(cachedAddress.DerivationStrategy, new[] {cachedAddress.KeyPath});
+                        .CancelReservation(cachedAddress.DerivationStrategy, new[] { cachedAddress.KeyPath });
                     this.TempData.SetStatusMessageModel(new StatusMessageModel()
                     {
                         AllowDismiss = true,
@@ -373,7 +373,7 @@ namespace BTCPayServer.Controllers
                     _WalletReceiveStateService.Set(walletId, reserve);
                     break;
             }
-            return RedirectToAction(nameof(WalletReceive), new {walletId});
+            return RedirectToAction(nameof(WalletReceive), new { walletId });
         }
 
         private async Task<bool> CanUseHotWallet()
@@ -384,7 +384,7 @@ namespace BTCPayServer.Controllers
             var policies = await _settingsRepository.GetSettingAsync<PoliciesSettings>();
             return policies?.AllowHotWalletForAll is true;
         }
-        
+
         [HttpGet]
         [Route("{walletId}/send")]
         public async Task<IActionResult> WalletSend(
@@ -405,7 +405,7 @@ namespace BTCPayServer.Controllers
             rateRules.Spread = 0.0m;
             var currencyPair = new Rating.CurrencyPair(paymentMethod.PaymentId.CryptoCode, GetCurrencyCode(storeData.DefaultLang) ?? "USD");
             double.TryParse(defaultAmount, out var amount);
-           var model = new WalletSendModel()
+            var model = new WalletSendModel()
             {
                 Outputs = new List<WalletSendModel.TransactionOutput>()
                 {
@@ -417,11 +417,11 @@ namespace BTCPayServer.Controllers
                 },
                 CryptoCode = walletId.CryptoCode
             };
-           if (!string.IsNullOrEmpty(bip21))
+            if (!string.IsNullOrEmpty(bip21))
-           {
+            {
-               LoadFromBIP21(model, bip21, network);
+                LoadFromBIP21(model, bip21, network);
-           }
+            }
-           var feeProvider = _feeRateProvider.CreateFeeProvider(network);
+            var feeProvider = _feeRateProvider.CreateFeeProvider(network);
             var recommendedFees =
                 new[]
                     {
@@ -433,7 +433,7 @@ namespace BTCPayServer.Controllers
                         {
                             var result = await feeProvider.GetFeeRateAsync(
                                 (int)network.NBitcoinNetwork.Consensus.GetExpectedBlocksFor(time));
-                            return new WalletSendModel.FeeRateOption() {Target = time, FeeRate = result.SatoshiPerByte};
+                            return new WalletSendModel.FeeRateOption() { Target = time, FeeRate = result.SatoshiPerByte };
                         }
                         catch (Exception)
                         {
@@ -446,7 +446,7 @@ namespace BTCPayServer.Controllers
                 .GetMetadataAsync<string>(GetDerivationSchemeSettings(walletId).AccountDerivation,
                     WellknownMetadataKeys.MasterHDKey));
             model.CurrentBalance = await balance;
-            
+
             await Task.WhenAll(recommendedFees);
             model.RecommendedSatoshiPerByte =
                 recommendedFees.Select(tuple => tuple.Result).Where(option => option != null).ToList();
@@ -474,7 +474,7 @@ namespace BTCPayServer.Controllers
             }
             return View(model);
         }
-        
+
 
         [HttpPost]
         [Route("{walletId}/send")]
@@ -498,11 +498,11 @@ namespace BTCPayServer.Controllers
             {
                 LoadFromBIP21(vm, bip21, network);
             }
-            
+
-            decimal transactionAmountSum  = 0;
+            decimal transactionAmountSum = 0;
             if (command == "toggle-input-selection")
             {
-                vm.InputSelection = !vm.InputSelection;  
+                vm.InputSelection = !vm.InputSelection;
             }
             if (vm.InputSelection)
             {
@@ -510,7 +510,7 @@ namespace BTCPayServer.Controllers
                 var walletBlobAsync = await WalletRepository.GetWalletInfo(walletId);
                 var walletTransactionsInfoAsync = await WalletRepository.GetWalletTransactionsInfo(walletId);
 
-                var utxos =  await _walletProvider.GetWallet(network).GetUnspentCoins(schemeSettings.AccountDerivation, cancellation);
+                var utxos = await _walletProvider.GetWallet(network).GetUnspentCoins(schemeSettings.AccountDerivation, cancellation);
                 vm.InputsAvailable = utxos.Select(coin =>
                 {
                     walletTransactionsInfoAsync.TryGetValue(coin.OutPoint.Hash.ToString(), out var info);
@@ -519,7 +519,7 @@ namespace BTCPayServer.Controllers
                         Outpoint = coin.OutPoint.ToString(),
                         Amount = coin.Value.GetValue(network),
                         Comment = info?.Comment,
-                        Labels = info == null? null : _labelFactory.GetLabels(walletBlobAsync, info, Request),
+                        Labels = info == null ? null : _labelFactory.GetLabels(walletBlobAsync, info, Request),
                         Link = string.Format(CultureInfo.InvariantCulture, network.BlockExplorerLink, coin.OutPoint.Hash.ToString())
                     };
                 }).ToArray();
@@ -544,7 +544,7 @@ namespace BTCPayServer.Controllers
             if (command.StartsWith("remove-output", StringComparison.InvariantCultureIgnoreCase))
             {
                 ModelState.Clear();
-                var index = int.Parse(command.Substring(command.IndexOf(":",StringComparison.InvariantCultureIgnoreCase) + 1),  CultureInfo.InvariantCulture);
+                var index = int.Parse(command.Substring(command.IndexOf(":", StringComparison.InvariantCultureIgnoreCase) + 1), CultureInfo.InvariantCulture);
                 vm.Outputs.RemoveAt(index);
                 return View(vm);
             }
@@ -569,12 +569,12 @@ namespace BTCPayServer.Controllers
 
                 try
                 {
-                    BitcoinAddress.Create(transactionOutput.DestinationAddress, network.NBitcoinNetwork);    
+                    BitcoinAddress.Create(transactionOutput.DestinationAddress, network.NBitcoinNetwork);
                 }
                 catch
                 {
-                    var inputName = 
+                    var inputName =
-                        string.Format(CultureInfo.InvariantCulture, "Outputs[{0}].", i.ToString(CultureInfo.InvariantCulture)) + 
+                        string.Format(CultureInfo.InvariantCulture, "Outputs[{0}].", i.ToString(CultureInfo.InvariantCulture)) +
                         nameof(transactionOutput.DestinationAddress);
 
                     ModelState.AddModelError(inputName, "Invalid address");
@@ -599,7 +599,8 @@ namespace BTCPayServer.Controllers
                     vm.AddModelError(model => model.Outputs[subtractFeesOutput].SubtractFeesFromOutput,
                         "You can only subtract fees from one output", this);
                 }
-            }else if (vm.CurrentBalance == transactionAmountSum && !substractFees)
+            }
+            else if (vm.CurrentBalance == transactionAmountSum && !substractFees)
             {
                 ModelState.AddModelError(string.Empty,
                     "You are sending your entire balance, you should subtract the fees from an output");
@@ -633,7 +634,7 @@ namespace BTCPayServer.Controllers
                 }
             }
 
-            if (!ModelState.IsValid) 
+            if (!ModelState.IsValid)
                 return View(vm);
 
             DerivationSchemeSettings derivationScheme = GetDerivationSchemeSettings(walletId);
@@ -658,15 +659,16 @@ namespace BTCPayServer.Controllers
             var signingContext = new SigningContextModel()
             {
                 PayJoinEndpointUrl = vm.PayJoinEndpointUrl,
-                EnforceLowR = psbt.Suggestions?.ShouldEnforceLowR
+                EnforceLowR = psbt.Suggestions?.ShouldEnforceLowR,
+                ChangeAddress = psbt.ChangeAddress?.ToString()
             };
 
-            var res = await TryHandleSigningCommands(walletId, psbt.PSBT, command, signingContext, psbt.ChangeAddress);
+            var res = await TryHandleSigningCommands(walletId, psbt.PSBT, command, signingContext);
             if (res != null)
             {
                 return res;
             }
-            
+
             switch (command)
             {
                 case "analyze-psbt":
@@ -681,7 +683,7 @@ namespace BTCPayServer.Controllers
                 default:
                     return View(vm);
             }
-            
+
         }
 
         private void LoadFromBIP21(WalletSendModel vm, string bip21, BTCPayNetwork network)
@@ -740,14 +742,12 @@ namespace BTCPayServer.Controllers
             ModelState.Clear();
         }
 
-        private IActionResult ViewVault(WalletId walletId, PSBT psbt, SigningContextModel signingContext, PSBT originalPSBT = null)
+        private IActionResult ViewVault(WalletId walletId, SigningContextModel signingContext)
         {
             return View(nameof(WalletSendVault), new WalletSendVaultModel()
             {
                 SigningContext = signingContext,
                 WalletId = walletId.ToString(),
-                OriginalPSBT = originalPSBT?.ToBase64(),
-                PSBT = psbt.ToBase64(),
                 WebsocketPath = this.Url.Action(nameof(VaultController.VaultBridgeConnection), "Vault", new { walletId = walletId.ToString() })
             });
         }
@@ -759,8 +759,6 @@ namespace BTCPayServer.Controllers
         {
             return RedirectToWalletPSBTReady(new WalletPSBTReadyViewModel()
             {
-                PSBT = model.PSBT,
-                OriginalPSBT = model.OriginalPSBT,
                 SigningContext = model.SigningContext
             });
         }
@@ -772,18 +770,25 @@ namespace BTCPayServer.Controllers
                 AspAction = nameof(WalletPSBTReady),
                 Parameters =
                 {
-                    new KeyValuePair<string, string>("psbt", vm.PSBT),
-                    new KeyValuePair<string, string>("originalPsbt", vm.OriginalPSBT),
-                    new KeyValuePair<string, string>("SigningContext.PayJoinEndpointUrl", vm.SigningContext?.PayJoinEndpointUrl),
-                    new KeyValuePair<string, string>("SigningContext.EnforceLowR", vm.SigningContext?.EnforceLowR?.ToString(CultureInfo.InvariantCulture)),
                     new KeyValuePair<string, string>("SigningKey", vm.SigningKey),
                     new KeyValuePair<string, string>("SigningKeyPath", vm.SigningKeyPath)
                 }
             };
-            
+            AddSigningContext(redirectVm, vm.SigningContext);
             return View("PostRedirect", redirectVm);
         }
-        
+
+        private void AddSigningContext(PostRedirectViewModel redirectVm, SigningContextModel signingContext)
+        {
+            if (signingContext is null)
+                return;
+            redirectVm.Parameters.Add(new KeyValuePair<string, string>("SigningContext.PSBT", signingContext.PSBT));
+            redirectVm.Parameters.Add(new KeyValuePair<string, string>("SigningContext.OriginalPSBT", signingContext.OriginalPSBT));
+            redirectVm.Parameters.Add(new KeyValuePair<string, string>("SigningContext.PayJoinEndpointUrl", signingContext.PayJoinEndpointUrl));
+            redirectVm.Parameters.Add(new KeyValuePair<string, string>("SigningContext.EnforceLowR", signingContext.EnforceLowR?.ToString(CultureInfo.InvariantCulture)));
+            redirectVm.Parameters.Add(new KeyValuePair<string, string>("SigningContext.ChangeAddress", signingContext.ChangeAddress));
+        }
+
         private IActionResult RedirectToWalletPSBT(WalletPSBTViewModel vm)
         {
             var redirectVm = new PostRedirectViewModel()
@@ -793,18 +798,17 @@ namespace BTCPayServer.Controllers
                 Parameters =
                 {
                     new KeyValuePair<string, string>("psbt", vm.PSBT),
-                    new KeyValuePair<string, string>("fileName", vm.FileName),
+                    new KeyValuePair<string, string>("fileName", vm.FileName)
-                    new KeyValuePair<string, string>("SigningContext.PayJoinEndpointUrl", vm.SigningContext?.PayJoinEndpointUrl),
-                    new KeyValuePair<string, string>("SigningContext.EnforceLowR", vm.SigningContext?.EnforceLowR?.ToString(CultureInfo.InvariantCulture)),
                 }
             };
+            AddSigningContext(redirectVm, vm.SigningContext);
             return View("PostRedirect", redirectVm);
         }
 
-        void SetAmbientPSBT(PSBT psbt)
+        void SetAmbientPSBT(string psbt)
         {
             if (psbt != null)
-                TempData["AmbientPSBT"] = psbt.ToBase64();
+                TempData["AmbientPSBT"] = psbt;
             else
                 TempData.Remove("AmbientPSBT");
         }
@@ -823,17 +827,16 @@ namespace BTCPayServer.Controllers
             return null;
         }
 
-        private ViewResult ViewWalletSendLedger(WalletId walletId, PSBT psbt, BitcoinAddress hintChange = null)
+        private ViewResult ViewWalletSendLedger(WalletId walletId, SigningContextModel signingContext)
         {
-            SetAmbientPSBT(psbt);
+            SetAmbientPSBT(signingContext.PSBT);
             return View("WalletSendLedger", new WalletSendLedgerModel()
             {
-                PSBT = psbt.ToBase64(),
+                SigningContext = signingContext,
-                HintChange = hintChange?.ToString(),
                 WebsocketPath = this.Url.Action(nameof(LedgerConnection), new { walletId = walletId.ToString() })
             });
         }
-      
+
         [HttpPost]
         [Route("{walletId}/ledger")]
         public IActionResult SubmitLedger([ModelBinder(typeof(WalletIdModelBinder))]
@@ -841,18 +844,17 @@ namespace BTCPayServer.Controllers
         {
             return RedirectToWalletPSBTReady(new WalletPSBTReadyViewModel()
             {
-                PSBT = model.PSBT
+                SigningContext = model.SigningContext
             });
         }
-        
+
         [HttpGet("{walletId}/psbt/seed")]
         public IActionResult SignWithSeed([ModelBinder(typeof(WalletIdModelBinder))]
-            WalletId walletId,string psbt, SigningContextModel signingContext)
+            WalletId walletId, SigningContextModel signingContext)
         {
             return View(nameof(SignWithSeed), new SignWithSeedViewModel()
             {
                 SigningContext = signingContext,
-                PSBT = psbt
             });
         }
 
@@ -876,11 +878,11 @@ namespace BTCPayServer.Controllers
                     "Seed or Key was not in a valid format. It is either the 12/24 words or starts with xprv");
             }
 
-            var psbt = PSBT.Parse(viewModel.PSBT, network.NBitcoinNetwork);
+            var psbt = PSBT.Parse(viewModel.SigningContext.PSBT, network.NBitcoinNetwork);
 
             if (!psbt.IsReadyToSign())
             {
-                ModelState.AddModelError(nameof(viewModel.PSBT), "PSBT is not ready to be signed");
+                ModelState.AddModelError(nameof(viewModel.SigningContext.PSBT), "PSBT is not ready to be signed");
             }
 
             if (!ModelState.IsValid)
@@ -898,7 +900,7 @@ namespace BTCPayServer.Controllers
             if (rootedKeyPath == null)
             {
                 ModelState.AddModelError(nameof(viewModel.SeedOrKey), "The master fingerprint and/or account key path of your seed are not set in the wallet settings.");
-                return View("SignWithSeed", viewModel);
+                return View(nameof(SignWithSeed), viewModel);
             }
             // The user gave the root key, let's try to rebase the PSBT, and derive the account private key
             if (rootedKeyPath.MasterFingerprint == extKey.GetPublicKey().GetHDFingerPrint())
@@ -918,18 +920,17 @@ namespace BTCPayServer.Controllers
                 ModelState.AddModelError(nameof(viewModel.SeedOrKey), "Impossible to sign the transaction. Probable cause: Incorrect account key path in wallet settings, PSBT already signed.");
                 return View(viewModel);
             }
-            ModelState.Remove(nameof(viewModel.PSBT));
+            ModelState.Remove(nameof(viewModel.SigningContext.PSBT));
+            viewModel.SigningContext.PSBT = psbt.ToBase64();
             return RedirectToWalletPSBTReady(new WalletPSBTReadyViewModel()
             {
-                PSBT = psbt.ToBase64(),
                 SigningKey = signingKey.GetWif(network.NBitcoinNetwork).ToString(),
                 SigningKeyPath = rootedKeyPath?.ToString(),
-                OriginalPSBT = viewModel.OriginalPSBT,
                 SigningContext = viewModel.SigningContext
             });
         }
-        
+
-        
+
         private bool PSBTChanged(PSBT psbt, Action act)
         {
             var before = psbt.ToBase64();
@@ -1271,14 +1272,15 @@ namespace BTCPayServer.Controllers
             }
             else if (command == "view-seed" && await CanUseHotWallet())
             {
-                var seed =  await ExplorerClientProvider.GetExplorerClient(walletId.CryptoCode)
+                var seed = await ExplorerClientProvider.GetExplorerClient(walletId.CryptoCode)
                     .GetMetadataAsync<string>(derivationScheme.AccountDerivation,
                         WellknownMetadataKeys.Mnemonic, cancellationToken);
                 if (string.IsNullOrEmpty(seed))
                 {
                     TempData.SetStatusMessageModel(new StatusMessageModel()
                     {
-                        Severity = StatusMessageModel.StatusSeverity.Error, Message = "The seed was not found"
+                        Severity = StatusMessageModel.StatusSeverity.Error,
+                        Message = "The seed was not found"
                     });
                 }
                 else
@@ -1289,7 +1291,7 @@ namespace BTCPayServer.Controllers
                         Html = $"Please store your seed securely! <br/><code class=\"alert-link\">{seed}</code>"
                     });
                 }
-                
+
                 return RedirectToAction(nameof(WalletSettings));
             }
             else

BTCPayServer/Models/WalletViewModels/SignWithSeedViewModel.cs

@@ -7,11 +7,10 @@ namespace BTCPayServer.Models.WalletViewModels
 {
     public class SignWithSeedViewModel
     {
-        public string OriginalPSBT  { get; set; }
         public SigningContextModel SigningContext { get; set; } = new SigningContextModel();
+
         [Required]
-        public string PSBT { get; set; }
+        [Display(Name = "BIP39 Seed (12/24 word mnemonic phrase) or HD private key (xprv...)")]
-        [Required][Display(Name = "BIP39 Seed (12/24 word mnemonic phrase) or HD private key (xprv...)")]
         public string SeedOrKey { get; set; }
 
         [Display(Name = "Optional seed passphrase")]

BTCPayServer/Models/WalletViewModels/SigningContextModel.cs

@@ -7,7 +7,10 @@ namespace BTCPayServer.Models.WalletViewModels
 {
     public class SigningContextModel
     {
+        public string PSBT { get; set; }
+        public string OriginalPSBT { get; set; }
         public string PayJoinEndpointUrl { get; set; }
         public bool? EnforceLowR { get; set; }
+        public string ChangeAddress { get; set; }
     }
 }

BTCPayServer/Models/WalletViewModels/WalletPSBTReadyViewModel.cs

@@ -9,8 +9,6 @@ namespace BTCPayServer.Models.WalletViewModels
     public class WalletPSBTReadyViewModel
     {
         public SigningContextModel SigningContext { get; set; } = new SigningContextModel();
-        public string OriginalPSBT { get; set; }
-        public string PSBT { get; set; }
         public string SigningKey { get; set; }
         public string SigningKeyPath { get; set; }
         public string GlobalError { get; set; }

BTCPayServer/Models/WalletViewModels/WalletSendLedgerModel.cs

@@ -8,7 +8,6 @@ namespace BTCPayServer.Models.WalletViewModels
     public class WalletSendLedgerModel
     {
         public string WebsocketPath { get; set; }
-        public string PSBT { get; set; }
+        public SigningContextModel SigningContext { get; set; }
-        public string HintChange { get; set; }
     }
 }

BTCPayServer/Models/WalletViewModels/WalletSendVaultModel.cs

@@ -7,9 +7,7 @@ namespace BTCPayServer.Models.WalletViewModels
 {
     public class WalletSendVaultModel
     {
-        public string OriginalPSBT { get; set; }
         public string WalletId { get; set; }
-        public string PSBT { get; set; }
         public string WebsocketPath { get; set; }
         public SigningContextModel SigningContext { get; set; } = new SigningContextModel();
     }

BTCPayServer/Views/Wallets/SignWithSeed.cshtml

@@ -27,10 +27,7 @@
     <div class="col-md-10">
         <div asp-validation-summary="All" class="text-danger"></div>
         <form method="post" asp-action="SignWithSeed" asp-route-walletId="@this.Context.GetRouteValue("walletId")">
-            <input type="hidden" asp-for="OriginalPSBT" />
+            <partial name="SigningContext" for="SigningContext" />
-            <input type="hidden" asp-for="PSBT" />
-            <input type="hidden" asp-for="SigningContext.PayJoinEndpointUrl" />
-            <input type="hidden" asp-for="SigningContext.EnforceLowR" />
             <div class="form-group">
                 <label asp-for="SeedOrKey"></label>
                 <input asp-for="SeedOrKey" class="form-control" />

BTCPayServer/Views/Wallets/WalletPSBT.cshtml

@@ -30,8 +30,7 @@
             <div class="form-group">
                 <form method="post" asp-action="WalletPSBT" asp-route-walletId="@this.Context.GetRouteValue("walletId")">
                     <input type="hidden" asp-for="CryptoCode" />
-                    <input type="hidden" asp-for="SigningContext.PayJoinEndpointUrl" />
+                    <partial name="SigningContext" for="SigningContext" />
-                    <input type="hidden" asp-for="SigningContext.EnforceLowR" />
                     <input type="hidden" asp-for="NBXSeedAvailable" />
                     <input type="hidden" asp-for="PSBT" />
                     <input type="hidden" asp-for="FileName" />

BTCPayServer/Views/Wallets/WalletPSBTReady.cshtml

@@ -137,12 +137,9 @@
         <div class="row">
             <div class="col-lg-12 text-center">
                 <form method="post" asp-action="WalletPSBTReady" asp-route-walletId="@this.Context.GetRouteValue("walletId")">
-                    <input type="hidden" asp-for="PSBT" value="@Model.PSBT" />
-                    <input type="hidden" asp-for="OriginalPSBT" />
                     <input type="hidden" asp-for="SigningKey" />
                     <input type="hidden" asp-for="SigningKeyPath" />
-                    <input type="hidden" asp-for="SigningContext.PayJoinEndpointUrl" />
+                    <partial name="SigningContext" for="SigningContext" />
-                    <input type="hidden" asp-for="SigningContext.EnforceLowR" />
                     @if (!Model.HasErrors)
                     {
                         @if (!string.IsNullOrEmpty(Model.SigningContext?.PayJoinEndpointUrl))

BTCPayServer/Views/Wallets/WalletSendLedger.cshtml

@@ -21,8 +21,7 @@
 <div class="row">
     <div class="col-md-10">
         <form id="broadcastForm" asp-action="SubmitLedger" asp-route-walletId="@this.Context.GetRouteValue("walletId")" method="post" style="display:none;">
-            <input type="hidden" id="PSBT" asp-for="PSBT" value="@Model.PSBT"/>
+            <partial name="SigningContext" for="SigningContext" />
-            <input type="hidden" asp-for="HintChange" />
             <input type="hidden" asp-for="WebsocketPath" />
         </form>
         <p>

BTCPayServer/Views/Wallets/WalletSendVault.cshtml

@@ -22,11 +22,8 @@
     <div id="body" class="col-md-10">
         <form id="broadcastForm" asp-action="WalletSendVault" asp-route-walletId="@this.Context.GetRouteValue("walletId")" method="post" style="display:none;">
             <input type="hidden" id="WalletId" asp-for="WalletId" />
-            <input type="hidden" id="PSBT" asp-for="PSBT" value="@Model.PSBT" />
-            <input type="hidden" id="OriginalPSBT" asp-for="OriginalPSBT" value="@Model.OriginalPSBT" />
             <input type="hidden" asp-for="WebsocketPath" />
-            <input type="hidden" asp-for="SigningContext.PayJoinEndpointUrl" />
+            <partial name="SigningContext" for="SigningContext" />
-            <input type="hidden" asp-for="SigningContext.EnforceLowR" />
         </form>
         <div id="vaultPlaceholder"></div>
         <button id="vault-confirm" class="btn btn-primary" style="display:none;"></button>
@@ -52,13 +49,12 @@
             ws_uri += websocketPath;
             var html = $("#VaultConnection").html();
             $("#vaultPlaceholder").html(html);
-
             var vaultUI = new vaultui.VaultBridgeUI(ws_uri);
             if (await vaultUI.askForDevice() && await vaultUI.askSignPSBT({
                 walletId: $("#WalletId").val(),
-                psbt: $("#PSBT").val()
+                psbt: $("#SigningContext_PSBT").val()
             })) {
-                $("#PSBT").val(vaultUI.psbt);
+                $("#SigningContext_PSBT").val(vaultUI.psbt);
                 $("#broadcastForm").submit();
             }
         }

BTCPayServer/wwwroot/js/WalletSendLedger.js

@@ -1,6 +1,6 @@
 $(function () {
     var psbt = $("#PSBT").val();
-    var hintChange = $("#HintChange").val();
+    var hintChange = $("#SigningContext_ChangeAddress").val();
     var websocketPath = $("#WebsocketPath").val();
     
     var loc = window.location, ws_uri;
@@ -38,7 +38,6 @@
             return false;
         $(".crypto-info").css("display", "block");
         var args = "";
-        args += "&psbt=" + encodeURIComponent(psbt);
         args += "&hintChange=" + encodeURIComponent(hintChange);
         
         WriteAlert("warning", 'Please validate the transaction on your ledger');      
@@ -61,7 +60,7 @@
                 if (result.error) {
                     WriteAlert("danger", result.error);
                 } else {
-                    $("#PSBT").val(result.psbt);
+                    $("#SigningContext_PSBT").val(result.psbt);
                     $("#broadcastForm").submit();
                 }
             });