diff --git a/src/script/sign.h b/src/script/sign.h
--- a/src/script/sign.h
+++ b/src/script/sign.h
@@ -301,6 +301,9 @@
                     if (!utxo.IsNull()) {
                         throw std::ios_base::failure(
                             "Duplicate Key, input utxo already provided");
+                    } else if (key.size() != 1) {
+                        throw std::ios_base::failure(
+                            "utxo key is more than one byte type");
                     }
                     UnserializeFromVector(s, utxo);
                     break;
@@ -337,6 +340,9 @@
                         throw std::ios_base::failure(
                             "Duplicate Key, input sighash type already "
                             "provided");
+                    } else if (key.size() != 1) {
+                        throw std::ios_base::failure(
+                            "Sighash type key is more than one byte type");
                     }
                     UnserializeFromVector(s, sighash_type);
                     break;
@@ -345,6 +351,10 @@
                         throw std::ios_base::failure(
                             "Duplicate Key, input redeemScript already "
                             "provided");
+                    } else if (key.size() != 1) {
+                        throw std::ios_base::failure(
+                            "Input redeemScript key is more than one byte "
+                            "type");
                     }
                     s >> redeem_script;
                     break;
@@ -358,6 +368,9 @@
                         throw std::ios_base::failure(
                             "Duplicate Key, input final scriptSig already "
                             "provided");
+                    } else if (key.size() != 1) {
+                        throw std::ios_base::failure(
+                            "Final scriptSig key is more than one byte type");
                     }
                     s >> final_script_sig;
                     break;
@@ -439,6 +452,10 @@
                         throw std::ios_base::failure(
                             "Duplicate Key, output redeemScript already "
                             "provided");
+                    } else if (key.size() != 1) {
+                        throw std::ios_base::failure(
+                            "Output redeemScript key is more than one byte "
+                            "type");
                     }
                     s >> redeem_script;
                     break;
@@ -556,6 +573,10 @@
                     if (tx) {
                         throw std::ios_base::failure(
                             "Duplicate Key, unsigned tx already provided");
+                    } else if (key.size() != 1) {
+                        throw std::ios_base::failure(
+                            "Global unsigned tx key is more than one byte "
+                            "type");
                     }
                     CMutableTransaction mtx;
                     UnserializeFromVector(s, mtx);
diff --git a/test/functional/data/rpc_psbt.json b/test/functional/data/rpc_psbt.json
--- a/test/functional/data/rpc_psbt.json
+++ b/test/functional/data/rpc_psbt.json
@@ -4,7 +4,16 @@
         "cHNidP8BAHUCAAAAASaBcTce3/KF6Tet7qSze3gADAVmy7OtZGQXE8pCFxv2AAAAAAD+////AtPf9QUAAAAAGXapFNDFmQPFusKGh2DpD9UhpGZap2UgiKwA4fUFAAAAABepFDVF5uM7gyxHBQ8k0+65PJwDlIvHh7MuEwAAAQCsAQAAAAABAomjxx6rTSDgNxu7pMxpj6KVyUY6+i45f4UzzLYvlWflAQAAABcWABS+GNFSqbASA52vPafeT1M0nuy5hf////+G+KpDpx3/FEiJOlMKcjfva0YIu7LdLQFx5jrsakiQtAEAAAAXFgAU/j6e8adF6XTZAsQ1WUOryzS9U1P/////AgDC6wsAAAAAGXapFIXP8Ql/2eAIuzSvcJxiGXs4l4pIiKxy/gA=",
         "cHNidP8BAP0KAQIAAAACqwlJoIxa98SbghL0F+LxWrP1wz3PFTghqBOfh3pbe+QAAAAAakcwRAIgR1lmF5fAGwNrJZKJSGhiGDR9iYZLcZ4ff89X0eURZYcCIFMJ6r9Wqk2Ikf/REf3xM286KdqGbX+EhtdVRs7tr5MZASEDXNxh/HupccC1AaZGoqg7ECy0OIEhfKaC3Ibi1z+ogpL+////qwlJoIxa98SbghL0F+LxWrP1wz3PFTghqBOfh3pbe+QBAAAAAP7///8CYDvqCwAAAAAZdqkUdopAu9dAy+gdmI5x3ipNXHE5ax2IrI4kAAAAAAAAGXapFG9GILVT+glechue4O/p+gOcykWXiKwAAAAAAAABASAA4fUFAAAAABepFDVF5uM7gyxHBQ8k0+65PJwDlIvHhwEEFgAUhdE1N/LiZUBaNNuvqePdoB+4IwgAAAA=",
         "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",
-        "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"
+        "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",
+        "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",
+        "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",
+        "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",
+        "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",
+        "cHNidP8BAFUCAAAAASeaIyOl37UfxF8iD6WLD8E+HjNCeSqF1+Ns1jM7XLw5AAAAAAD/////AaBa6gsAAAAAGXapFP/pwAYQl8w7Y28ssEYPpPxCfStFiKwAAAAAAAEAIJVe6gsAAAAAF6kUY0UgD2jRieGtwN8cTRbqjxTA2+uHIgIDsTQcy6doO2r08SOM1ul+cWfVafrEfx5I1HVBhENVvUZGMEMCIAQktY7/qqaU4VWepck7v9SokGQiQFXN8HC2dxRpRC0HAh9cjrD+plFtYLisszrWTt5g6Hhb+zqpS5m9+GFR25qaAQEEIgAgdx/RitRZZm3Unz1WTj28QvTIR3TjYK2haBao7UiNVoEhBgOxNBzLp2g7avTxI4zW6X5xZ9Vp+sR/HkjUdUGEQ1W9ELSmumcAAACAAAAAgAQAAIAiBgPeVdHh2sgF4/iljB+/m5TALz26r+En/vykmV8m+CCDvRC0prpnAAAAgAAAAIAFAACAAQVHUiEDsTQcy6doO2r08SOM1ul+cWfVafrEfx5I1HVBhENVvUYhA95V0eHayAXj+KWMH7+blMAvPbqv4Sf+/KSZXyb4IIO9Uq4AAA==",
+        "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",
+        "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",
+        "cHNidP8BAHMCAAAAATAa6YblFqHsisW0vGVz0y+DtGXiOtdhZ9aLOOcwtNvbAAAAAAD/////AnR7AQAAAAAAF6kUA6oXrogrXQ1Usl1jEE5P/s57nqKHYEOZOwAAAAAXqRS5IbG6b3IuS/qDtlV6MTmYakLsg4cAAAAAAAEAHwDKmjsAAAAAFgAU0tlLZK4IWH7vyO6xh8YB6Tn5A3wCAwAEQQAAAAABABYAFGLp6YL/803YI5YQMWsJDNKjt0fLAAEAIgAgh2utgy8dFoAV7UEjKp6mWhgV2e8TwO+HWfZLWysnimUBASVRIQO3ziOgHFtL8ApkJTfN+rsxW2aDMoZ0eO9RMJ0r1X+Kh1GuAA==",
+        "cHNidP8BAHMCAAAAATAa6YblFqHsisW0vGVz0y+DtGXiOtdhZ9aLOOcwtNvbAAAAAAD/////AnR7AQAAAAAAF6kUA6oXrogrXQ1Usl1jEE5P/s57nqKHYEOZOwAAAAAXqRS5IbG6b3IuS/qDtlV6MTmYakLsg4cAAAAAAAACAAAWABRi6emC//NN2COWEDFrCQzSo7dHywACAAAiACCHa62DLx0WgBXtQSMqnqZaGBXZ7xPA74dZ9ktbKyeKZQEBJVEhA7fOI6AcW0vwCmQlN836uzFbZoMyhnR471EwnSvVf4qHUa4A"
     ],
     "valid" : [
         "cHNidP8BAHUCAAAAASaBcTce3/KF6Tet7qSze3gADAVmy7OtZGQXE8pCFxv2AAAAAAD+////AtPf9QUAAAAAGXapFNDFmQPFusKGh2DpD9UhpGZap2UgiKwA4fUFAAAAABepFDVF5uM7gyxHBQ8k0+65PJwDlIvHh7MuEwAAAQAiAMLrCwAAAAAZdqkUhc/xCX/Z4Ai7NK9wnGIZeziXikiIrAAAAA==",