diff --git a/src/consensus/validation.h b/src/consensus/validation.h
index 362c0be0b..6e34837a3 100644
--- a/src/consensus/validation.h
+++ b/src/consensus/validation.h
@@ -30,14 +30,17 @@ private:
     std::string strRejectReason;
     unsigned int chRejectCode;
     bool corruptionPossible;
+    std::string strDebugMessage;
 public:
     CValidationState() : mode(MODE_VALID), nDoS(0), chRejectCode(0), corruptionPossible(false) {}
     virtual bool DoS(int level, bool ret = false,
-             unsigned int chRejectCodeIn=0, std::string strRejectReasonIn="",
-             bool corruptionIn=false) {
+             unsigned int chRejectCodeIn=0, const std::string &strRejectReasonIn="",
+             bool corruptionIn=false,
+             const std::string &strDebugMessageIn="") {
         chRejectCode = chRejectCodeIn;
         strRejectReason = strRejectReasonIn;
         corruptionPossible = corruptionIn;
+        strDebugMessage = strDebugMessageIn;
         if (mode == MODE_ERROR)
             return ret;
         nDoS += level;
@@ -45,8 +48,9 @@ public:
         return ret;
     }
     virtual bool Invalid(bool ret = false,
-                 unsigned int _chRejectCode=0, std::string _strRejectReason="") {
-        return DoS(0, ret, _chRejectCode, _strRejectReason);
+                 unsigned int _chRejectCode=0, const std::string &_strRejectReason="",
+                 const std::string &_strDebugMessage="") {
+        return DoS(0, ret, _chRejectCode, _strRejectReason, false, _strDebugMessage);
     }
     virtual bool Error(const std::string& strRejectReasonIn) {
         if (mode == MODE_VALID)
@@ -75,6 +79,7 @@ public:
     }
     virtual unsigned int GetRejectCode() const { return chRejectCode; }
     virtual std::string GetRejectReason() const { return strRejectReason; }
+    virtual std::string GetDebugMessage() const { return strDebugMessage; }
 };
 
 #endif // BITCOIN_CONSENSUS_VALIDATION_H
diff --git a/src/gtest/test_checkblock.cpp b/src/gtest/test_checkblock.cpp
index 140813a62..3a61e5945 100644
--- a/src/gtest/test_checkblock.cpp
+++ b/src/gtest/test_checkblock.cpp
@@ -11,11 +11,13 @@
 
 class MockCValidationState : public CValidationState {
 public:
-    MOCK_METHOD5(DoS, bool(int level, bool ret,
-             unsigned int chRejectCodeIn, std::string strRejectReasonIn,
-             bool corruptionIn));
-    MOCK_METHOD3(Invalid, bool(bool ret,
-                 unsigned int _chRejectCode, std::string _strRejectReason));
+    MOCK_METHOD6(DoS, bool(int level, bool ret,
+             unsigned int chRejectCodeIn, const std::string strRejectReasonIn,
+             bool corruptionIn,
+             const std::string &strDebugMessageIn));
+    MOCK_METHOD4(Invalid, bool(bool ret,
+                 unsigned int _chRejectCode, const std::string _strRejectReason,
+                 const std::string &_strDebugMessage));
     MOCK_METHOD1(Error, bool(std::string strRejectReasonIn));
     MOCK_CONST_METHOD0(IsValid, bool());
     MOCK_CONST_METHOD0(IsInvalid, bool());
@@ -24,6 +26,7 @@ public:
     MOCK_CONST_METHOD0(CorruptionPossible, bool());
     MOCK_CONST_METHOD0(GetRejectCode, unsigned int());
     MOCK_CONST_METHOD0(GetRejectReason, std::string());
+    MOCK_CONST_METHOD0(GetDebugMessage, std::string());
 };
 
 TEST(CheckBlock, VersionTooLow) {
@@ -34,7 +37,7 @@ TEST(CheckBlock, VersionTooLow) {
     block.nVersion = 1;
 
     MockCValidationState state;
-    EXPECT_CALL(state, DoS(100, false, REJECT_INVALID, "version-too-low", false)).Times(1);
+    EXPECT_CALL(state, DoS(100, false, REJECT_INVALID, "version-too-low", false, "")).Times(1);
     EXPECT_FALSE(CheckBlock(block, state, Params(), verifier, orchardAuth, false, false, true));
 }
 
@@ -77,7 +80,7 @@ TEST(CheckBlock, BlockSproutRejectsBadVersion) {
     auto verifier = ProofVerifier::Strict();
     auto orchardAuth = orchard::AuthValidator::Batch();
 
-    EXPECT_CALL(state, DoS(100, false, REJECT_INVALID, "bad-txns-version-too-low", false)).Times(1);
+    EXPECT_CALL(state, DoS(100, false, REJECT_INVALID, "bad-txns-version-too-low", false, "")).Times(1);
     EXPECT_FALSE(CheckBlock(block, state, Params(), verifier, orchardAuth, false, false, true));
 }
 
@@ -149,7 +152,7 @@ protected:
 
         // We now expect this to be an invalid block, for the given reason.
         MockCValidationState state;
-        EXPECT_CALL(state, DoS(level, false, REJECT_INVALID, reason, false)).Times(1);
+        EXPECT_CALL(state, DoS(level, false, REJECT_INVALID, reason, false, "")).Times(1);
         EXPECT_FALSE(ContextualCheckBlock(block, state, Params(), &indexPrev, true));
     }
 
@@ -180,14 +183,14 @@ TEST_F(ContextualCheckBlockTest, BadCoinbaseHeight) {
     CBlock prev;
     CBlockIndex indexPrev {prev};
     indexPrev.nHeight = 0;
-    EXPECT_CALL(state, DoS(100, false, REJECT_INVALID, "bad-cb-height", false)).Times(1);
+    EXPECT_CALL(state, DoS(100, false, REJECT_INVALID, "bad-cb-height", false, "")).Times(1);
     EXPECT_FALSE(ContextualCheckBlock(block, state, Params(), &indexPrev, true));
 
     // Setting to an incorrect height should fail
     mtx.vin[0].scriptSig = CScript() << 2 << OP_0;
     CTransaction tx3 {mtx};
     block.vtx[0] = tx3;
-    EXPECT_CALL(state, DoS(100, false, REJECT_INVALID, "bad-cb-height", false)).Times(1);
+    EXPECT_CALL(state, DoS(100, false, REJECT_INVALID, "bad-cb-height", false, "")).Times(1);
     EXPECT_FALSE(ContextualCheckBlock(block, state, Params(), &indexPrev, true));
 
     // After correcting the scriptSig, should pass
diff --git a/src/gtest/test_checktransaction.cpp b/src/gtest/test_checktransaction.cpp
index 9c569e4ff..82b05e42e 100644
--- a/src/gtest/test_checktransaction.cpp
+++ b/src/gtest/test_checktransaction.cpp
@@ -41,11 +41,13 @@ TEST(ChecktransactionTests, CheckVpubNotBothNonzero) {
 
 class MockCValidationState : public CValidationState {
 public:
-    MOCK_METHOD5(DoS, bool(int level, bool ret,
-             unsigned int chRejectCodeIn, std::string strRejectReasonIn,
-             bool corruptionIn));
-    MOCK_METHOD3(Invalid, bool(bool ret,
-                 unsigned int _chRejectCode, std::string _strRejectReason));
+    MOCK_METHOD6(DoS, bool(int level, bool ret,
+             unsigned int chRejectCodeIn, const std::string &strRejectReasonIn,
+             bool corruptionIn,
+             const std::string &strDebugMessageIn));
+    MOCK_METHOD4(Invalid, bool(bool ret,
+                 unsigned int _chRejectCode, const std::string _strRejectReason,
+                 const std::string &_strDebugMessage));
     MOCK_METHOD1(Error, bool(std::string strRejectReasonIn));
     MOCK_CONST_METHOD0(IsValid, bool());
     MOCK_CONST_METHOD0(IsInvalid, bool());
@@ -54,6 +56,7 @@ public:
     MOCK_CONST_METHOD0(CorruptionPossible, bool());
     MOCK_CONST_METHOD0(GetRejectCode, unsigned int());
     MOCK_CONST_METHOD0(GetRejectReason, std::string());
+    MOCK_CONST_METHOD0(GetDebugMessage, std::string());
 };
 
 void CreateJoinSplitSignature(CMutableTransaction& mtx, uint32_t consensusBranchId);
@@ -135,7 +138,7 @@ TEST(ChecktransactionTests, BadVersionTooLow) {
     EXPECT_THROW((CTransaction(mtx)), std::ios_base::failure);
     UNSAFE_CTransaction tx(mtx);
     MockCValidationState state;
-    EXPECT_CALL(state, DoS(100, false, REJECT_INVALID, "bad-txns-version-too-low", false)).Times(1);
+    EXPECT_CALL(state, DoS(100, false, REJECT_INVALID, "bad-txns-version-too-low", false, "")).Times(1);
     CheckTransactionWithoutProofVerification(tx, state);
 }
 
@@ -146,7 +149,7 @@ TEST(ChecktransactionTests, BadTxnsVinEmpty) {
 
     CTransaction tx(mtx);
     MockCValidationState state;
-    EXPECT_CALL(state, DoS(10, false, REJECT_INVALID, "bad-txns-no-source-of-funds", false)).Times(1);
+    EXPECT_CALL(state, DoS(10, false, REJECT_INVALID, "bad-txns-no-source-of-funds", false, "")).Times(1);
     CheckTransactionWithoutProofVerification(tx, state);
 }
 
@@ -158,7 +161,7 @@ TEST(ChecktransactionTests, BadTxnsVoutEmpty) {
     CTransaction tx(mtx);
 
     MockCValidationState state;
-    EXPECT_CALL(state, DoS(10, false, REJECT_INVALID, "bad-txns-no-sink-of-funds", false)).Times(1);
+    EXPECT_CALL(state, DoS(10, false, REJECT_INVALID, "bad-txns-no-sink-of-funds", false, "")).Times(1);
     CheckTransactionWithoutProofVerification(tx, state);
 }
 
@@ -192,7 +195,7 @@ TEST(ChecktransactionTests, BadTxnsOversize) {
         EXPECT_TRUE(CheckTransactionWithoutProofVerification(tx, state));
 
         // ... but fails contextual ones!
-        EXPECT_CALL(state, DoS(100, false, REJECT_INVALID, "bad-txns-oversize", false)).Times(1);
+        EXPECT_CALL(state, DoS(100, false, REJECT_INVALID, "bad-txns-oversize", false, "")).Times(1);
         EXPECT_FALSE(ContextualCheckTransaction(tx, state, Params(), 1, true));
     }
 
@@ -270,7 +273,7 @@ TEST(ChecktransactionTests, OversizeSaplingTxns) {
         EXPECT_EQ(::GetSerializeSize(tx, SER_NETWORK, PROTOCOL_VERSION), MAX_TX_SIZE_AFTER_SAPLING + 1);
 
         MockCValidationState state;
-        EXPECT_CALL(state, DoS(100, false, REJECT_INVALID, "bad-txns-oversize", false)).Times(1);
+        EXPECT_CALL(state, DoS(100, false, REJECT_INVALID, "bad-txns-oversize", false, "")).Times(1);
         EXPECT_FALSE(CheckTransactionWithoutProofVerification(tx, state));
     }
 
@@ -286,7 +289,7 @@ TEST(ChecktransactionTests, BadTxnsVoutNegative) {
     UNSAFE_CTransaction tx(mtx);
 
     MockCValidationState state;
-    EXPECT_CALL(state, DoS(100, false, REJECT_INVALID, "bad-txns-vout-negative", false)).Times(1);
+    EXPECT_CALL(state, DoS(100, false, REJECT_INVALID, "bad-txns-vout-negative", false, "")).Times(1);
     CheckTransactionWithoutProofVerification(tx, state);
 }
 
@@ -298,7 +301,7 @@ TEST(ChecktransactionTests, BadTxnsVoutToolarge) {
     UNSAFE_CTransaction tx(mtx);
 
     MockCValidationState state;
-    EXPECT_CALL(state, DoS(100, false, REJECT_INVALID, "bad-txns-vout-toolarge", false)).Times(1);
+    EXPECT_CALL(state, DoS(100, false, REJECT_INVALID, "bad-txns-vout-toolarge", false, "")).Times(1);
     CheckTransactionWithoutProofVerification(tx, state);
 }
 
@@ -310,7 +313,7 @@ TEST(ChecktransactionTests, BadTxnsTxouttotalToolargeOutputs) {
     CTransaction tx(mtx);
 
     MockCValidationState state;
-    EXPECT_CALL(state, DoS(100, false, REJECT_INVALID, "bad-txns-txouttotal-toolarge", false)).Times(1);
+    EXPECT_CALL(state, DoS(100, false, REJECT_INVALID, "bad-txns-txouttotal-toolarge", false, "")).Times(1);
     CheckTransactionWithoutProofVerification(tx, state);
 }
 
@@ -321,7 +324,7 @@ TEST(ChecktransactionTests, ValueBalanceNonZero) {
     CTransaction tx(mtx);
 
     MockCValidationState state;
-    EXPECT_CALL(state, DoS(100, false, REJECT_INVALID, "bad-txns-valuebalance-nonzero", false)).Times(1);
+    EXPECT_CALL(state, DoS(100, false, REJECT_INVALID, "bad-txns-valuebalance-nonzero", false, "")).Times(1);
     CheckTransactionWithoutProofVerification(tx, state);
 }
 
@@ -333,7 +336,7 @@ TEST(ChecktransactionTests, PositiveValueBalanceTooLarge) {
     CTransaction tx(mtx);
 
     MockCValidationState state;
-    EXPECT_CALL(state, DoS(100, false, REJECT_INVALID, "bad-txns-valuebalance-toolarge", false)).Times(1);
+    EXPECT_CALL(state, DoS(100, false, REJECT_INVALID, "bad-txns-valuebalance-toolarge", false, "")).Times(1);
     CheckTransactionWithoutProofVerification(tx, state);
 }
 
@@ -345,7 +348,7 @@ TEST(ChecktransactionTests, NegativeValueBalanceTooLarge) {
     CTransaction tx(mtx);
 
     MockCValidationState state;
-    EXPECT_CALL(state, DoS(100, false, REJECT_INVALID, "bad-txns-valuebalance-toolarge", false)).Times(1);
+    EXPECT_CALL(state, DoS(100, false, REJECT_INVALID, "bad-txns-valuebalance-toolarge", false, "")).Times(1);
     CheckTransactionWithoutProofVerification(tx, state);
 }
 
@@ -358,7 +361,7 @@ TEST(ChecktransactionTests, ValueBalanceOverflowsTotal) {
     CTransaction tx(mtx);
 
     MockCValidationState state;
-    EXPECT_CALL(state, DoS(100, false, REJECT_INVALID, "bad-txns-txouttotal-toolarge", false)).Times(1);
+    EXPECT_CALL(state, DoS(100, false, REJECT_INVALID, "bad-txns-txouttotal-toolarge", false, "")).Times(1);
     CheckTransactionWithoutProofVerification(tx, state);
 }
 
@@ -370,7 +373,7 @@ TEST(ChecktransactionTests, BadTxnsTxouttotalToolargeJoinsplit) {
     CTransaction tx(mtx);
 
     MockCValidationState state;
-    EXPECT_CALL(state, DoS(100, false, REJECT_INVALID, "bad-txns-txouttotal-toolarge", false)).Times(1);
+    EXPECT_CALL(state, DoS(100, false, REJECT_INVALID, "bad-txns-txouttotal-toolarge", false, "")).Times(1);
     CheckTransactionWithoutProofVerification(tx, state);
 }
 
@@ -382,7 +385,7 @@ TEST(ChecktransactionTests, BadTxnsTxintotalToolargeJoinsplit) {
     CTransaction tx(mtx);
 
     MockCValidationState state;
-    EXPECT_CALL(state, DoS(100, false, REJECT_INVALID, "bad-txns-txintotal-toolarge", false)).Times(1);
+    EXPECT_CALL(state, DoS(100, false, REJECT_INVALID, "bad-txns-txintotal-toolarge", false, "")).Times(1);
     CheckTransactionWithoutProofVerification(tx, state);
 }
 
@@ -393,7 +396,7 @@ TEST(ChecktransactionTests, BadTxnsVpubOldNegative) {
     CTransaction tx(mtx);
 
     MockCValidationState state;
-    EXPECT_CALL(state, DoS(100, false, REJECT_INVALID, "bad-txns-vpub_old-negative", false)).Times(1);
+    EXPECT_CALL(state, DoS(100, false, REJECT_INVALID, "bad-txns-vpub_old-negative", false, "")).Times(1);
     CheckTransactionWithoutProofVerification(tx, state);
 }
 
@@ -404,7 +407,7 @@ TEST(ChecktransactionTests, BadTxnsVpubNewNegative) {
     CTransaction tx(mtx);
 
     MockCValidationState state;
-    EXPECT_CALL(state, DoS(100, false, REJECT_INVALID, "bad-txns-vpub_new-negative", false)).Times(1);
+    EXPECT_CALL(state, DoS(100, false, REJECT_INVALID, "bad-txns-vpub_new-negative", false, "")).Times(1);
     CheckTransactionWithoutProofVerification(tx, state);
 }
 
@@ -415,7 +418,7 @@ TEST(ChecktransactionTests, BadTxnsVpubOldToolarge) {
     CTransaction tx(mtx);
 
     MockCValidationState state;
-    EXPECT_CALL(state, DoS(100, false, REJECT_INVALID, "bad-txns-vpub_old-toolarge", false)).Times(1);
+    EXPECT_CALL(state, DoS(100, false, REJECT_INVALID, "bad-txns-vpub_old-toolarge", false, "")).Times(1);
     CheckTransactionWithoutProofVerification(tx, state);
 }
 
@@ -426,7 +429,7 @@ TEST(ChecktransactionTests, BadTxnsVpubNewToolarge) {
     CTransaction tx(mtx);
 
     MockCValidationState state;
-    EXPECT_CALL(state, DoS(100, false, REJECT_INVALID, "bad-txns-vpub_new-toolarge", false)).Times(1);
+    EXPECT_CALL(state, DoS(100, false, REJECT_INVALID, "bad-txns-vpub_new-toolarge", false, "")).Times(1);
     CheckTransactionWithoutProofVerification(tx, state);
 }
 
@@ -438,7 +441,7 @@ TEST(ChecktransactionTests, BadTxnsVpubsBothNonzero) {
     CTransaction tx(mtx);
 
     MockCValidationState state;
-    EXPECT_CALL(state, DoS(100, false, REJECT_INVALID, "bad-txns-vpubs-both-nonzero", false)).Times(1);
+    EXPECT_CALL(state, DoS(100, false, REJECT_INVALID, "bad-txns-vpubs-both-nonzero", false, "")).Times(1);
     CheckTransactionWithoutProofVerification(tx, state);
 }
 
@@ -450,7 +453,7 @@ TEST(ChecktransactionTests, BadTxnsInputsDuplicate) {
     CTransaction tx(mtx);
 
     MockCValidationState state;
-    EXPECT_CALL(state, DoS(100, false, REJECT_INVALID, "bad-txns-inputs-duplicate", false)).Times(1);
+    EXPECT_CALL(state, DoS(100, false, REJECT_INVALID, "bad-txns-inputs-duplicate", false, "")).Times(1);
     CheckTransactionWithoutProofVerification(tx, state);
 }
 
@@ -462,7 +465,7 @@ TEST(ChecktransactionTests, BadJoinsplitsNullifiersDuplicateSameJoinsplit) {
     CTransaction tx(mtx);
 
     MockCValidationState state;
-    EXPECT_CALL(state, DoS(100, false, REJECT_INVALID, "bad-joinsplits-nullifiers-duplicate", false)).Times(1);
+    EXPECT_CALL(state, DoS(100, false, REJECT_INVALID, "bad-joinsplits-nullifiers-duplicate", false, "")).Times(1);
     CheckTransactionWithoutProofVerification(tx, state);
 }
 
@@ -474,7 +477,7 @@ TEST(ChecktransactionTests, BadJoinsplitsNullifiersDuplicateDifferentJoinsplit)
     CTransaction tx(mtx);
 
     MockCValidationState state;
-    EXPECT_CALL(state, DoS(100, false, REJECT_INVALID, "bad-joinsplits-nullifiers-duplicate", false)).Times(1);
+    EXPECT_CALL(state, DoS(100, false, REJECT_INVALID, "bad-joinsplits-nullifiers-duplicate", false, "")).Times(1);
     CheckTransactionWithoutProofVerification(tx, state);
 }
 
@@ -490,7 +493,7 @@ TEST(ChecktransactionTests, BadCbHasJoinsplits) {
     EXPECT_TRUE(tx.IsCoinBase());
 
     MockCValidationState state;
-    EXPECT_CALL(state, DoS(100, false, REJECT_INVALID, "bad-cb-has-joinsplits", false)).Times(1);
+    EXPECT_CALL(state, DoS(100, false, REJECT_INVALID, "bad-cb-has-joinsplits", false, "")).Times(1);
     CheckTransactionWithoutProofVerification(tx, state);
 }
 
@@ -506,7 +509,7 @@ TEST(ChecktransactionTests, BadCbEmptyScriptsig) {
     EXPECT_TRUE(tx.IsCoinBase());
 
     MockCValidationState state;
-    EXPECT_CALL(state, DoS(100, false, REJECT_INVALID, "bad-cb-length", false)).Times(1);
+    EXPECT_CALL(state, DoS(100, false, REJECT_INVALID, "bad-cb-length", false, "")).Times(1);
     CheckTransactionWithoutProofVerification(tx, state);
 }
 
@@ -518,7 +521,7 @@ TEST(ChecktransactionTests, BadTxnsPrevoutNull) {
     EXPECT_FALSE(tx.IsCoinBase());
 
     MockCValidationState state;
-    EXPECT_CALL(state, DoS(10, false, REJECT_INVALID, "bad-txns-prevout-null", false)).Times(1);
+    EXPECT_CALL(state, DoS(10, false, REJECT_INVALID, "bad-txns-prevout-null", false, "")).Times(1);
     CheckTransactionWithoutProofVerification(tx, state);
 }
 
@@ -533,15 +536,15 @@ TEST(ChecktransactionTests, BadTxnsInvalidJoinsplitSignature) {
     MockCValidationState state;
     // during initial block download, for transactions being accepted into the
     // mempool (and thus not mined), DoS ban score should be zero, else 10
-    EXPECT_CALL(state, DoS(0, false, REJECT_INVALID, "bad-txns-invalid-joinsplit-signature", false)).Times(1);
+    EXPECT_CALL(state, DoS(0, false, REJECT_INVALID, "bad-txns-invalid-joinsplit-signature", false, "")).Times(1);
     ContextualCheckTransaction(tx, state, chainparams, 0, false, [](const Consensus::Params&) { return true; });
-    EXPECT_CALL(state, DoS(10, false, REJECT_INVALID, "bad-txns-invalid-joinsplit-signature", false)).Times(1);
+    EXPECT_CALL(state, DoS(10, false, REJECT_INVALID, "bad-txns-invalid-joinsplit-signature", false, "")).Times(1);
     ContextualCheckTransaction(tx, state, chainparams, 0, false, [](const Consensus::Params&) { return false; });
     // for transactions that have been mined in a block, DoS ban score should
     // always be 100.
-    EXPECT_CALL(state, DoS(100, false, REJECT_INVALID, "bad-txns-invalid-joinsplit-signature", false)).Times(1);
+    EXPECT_CALL(state, DoS(100, false, REJECT_INVALID, "bad-txns-invalid-joinsplit-signature", false, "")).Times(1);
     ContextualCheckTransaction(tx, state, chainparams, 0, true, [](const Consensus::Params&) { return true; });
-    EXPECT_CALL(state, DoS(100, false, REJECT_INVALID, "bad-txns-invalid-joinsplit-signature", false)).Times(1);
+    EXPECT_CALL(state, DoS(100, false, REJECT_INVALID, "bad-txns-invalid-joinsplit-signature", false, "")).Times(1);
     ContextualCheckTransaction(tx, state, chainparams, 0, true, [](const Consensus::Params&) { return false; });
 }
 
@@ -573,7 +576,7 @@ TEST(ChecktransactionTests, JoinsplitSignatureDetectsOldBranchId) {
         strprintf("old-consensus-branch-id (Expected %s, found %s)",
             HexInt(blossomBranchId),
             HexInt(saplingBranchId)),
-        false)).Times(1);
+        false, "")).Times(1);
     EXPECT_FALSE(ContextualCheckTransaction(
         tx, state, chainparams, 15, false,
         [](const Consensus::Params&) { return false; }));
@@ -583,7 +586,7 @@ TEST(ChecktransactionTests, JoinsplitSignatureDetectsOldBranchId) {
     // network upgrade back.
     EXPECT_CALL(state, DoS(
         10, false, REJECT_INVALID,
-        "bad-txns-invalid-joinsplit-signature", false)).Times(1);
+        "bad-txns-invalid-joinsplit-signature", false, "")).Times(1);
     EXPECT_FALSE(ContextualCheckTransaction(
         tx, state, chainparams, 25, false,
         [](const Consensus::Params&) { return false; }));
@@ -625,15 +628,15 @@ TEST(ChecktransactionTests, NonCanonicalEd25519Signature) {
     MockCValidationState state;
     // during initial block download, for transactions being accepted into the
     // mempool (and thus not mined), DoS ban score should be zero, else 10
-    EXPECT_CALL(state, DoS(0, false, REJECT_INVALID, "bad-txns-invalid-joinsplit-signature", false)).Times(1);
+    EXPECT_CALL(state, DoS(0, false, REJECT_INVALID, "bad-txns-invalid-joinsplit-signature", false, "")).Times(1);
     ContextualCheckTransaction(tx, state, chainparams, 0, false, [](const Consensus::Params&) { return true; });
-    EXPECT_CALL(state, DoS(10, false, REJECT_INVALID, "bad-txns-invalid-joinsplit-signature", false)).Times(1);
+    EXPECT_CALL(state, DoS(10, false, REJECT_INVALID, "bad-txns-invalid-joinsplit-signature", false, "")).Times(1);
     ContextualCheckTransaction(tx, state, chainparams, 0, false, [](const Consensus::Params&) { return false; });
     // for transactions that have been mined in a block, DoS ban score should
     // always be 100.
-    EXPECT_CALL(state, DoS(100, false, REJECT_INVALID, "bad-txns-invalid-joinsplit-signature", false)).Times(1);
+    EXPECT_CALL(state, DoS(100, false, REJECT_INVALID, "bad-txns-invalid-joinsplit-signature", false, "")).Times(1);
     ContextualCheckTransaction(tx, state, chainparams, 0, true, [](const Consensus::Params&) { return true; });
-    EXPECT_CALL(state, DoS(100, false, REJECT_INVALID, "bad-txns-invalid-joinsplit-signature", false)).Times(1);
+    EXPECT_CALL(state, DoS(100, false, REJECT_INVALID, "bad-txns-invalid-joinsplit-signature", false, "")).Times(1);
     ContextualCheckTransaction(tx, state, chainparams, 0, true, [](const Consensus::Params&) { return false; });
 }
 
@@ -769,7 +772,7 @@ TEST(ChecktransactionTests, OverwinterExpiryHeight) {
         CTransaction tx(mtx);
         MockCValidationState state;
         EXPECT_TRUE(CheckTransactionWithoutProofVerification(tx, state));
-        EXPECT_CALL(state, DoS(100, false, REJECT_INVALID, "bad-tx-expiry-height-too-high", false)).Times(1);
+        EXPECT_CALL(state, DoS(100, false, REJECT_INVALID, "bad-tx-expiry-height-too-high", false, "")).Times(1);
         ContextualCheckTransaction(tx, state, params, 1, true);
     }
 
@@ -778,7 +781,7 @@ TEST(ChecktransactionTests, OverwinterExpiryHeight) {
         CTransaction tx(mtx);
         MockCValidationState state;
         EXPECT_TRUE(CheckTransactionWithoutProofVerification(tx, state));
-        EXPECT_CALL(state, DoS(100, false, REJECT_INVALID, "bad-tx-expiry-height-too-high", false)).Times(1);
+        EXPECT_CALL(state, DoS(100, false, REJECT_INVALID, "bad-tx-expiry-height-too-high", false, "")).Times(1);
         ContextualCheckTransaction(tx, state, params, 1, true);
     }
 
@@ -805,7 +808,7 @@ TEST(ChecktransactionTests, SproutTxVersionTooLow) {
     EXPECT_THROW((CTransaction(mtx)), std::ios_base::failure);
     UNSAFE_CTransaction tx(mtx);
     MockCValidationState state;
-    EXPECT_CALL(state, DoS(100, false, REJECT_INVALID, "bad-txns-version-too-low", false)).Times(1);
+    EXPECT_CALL(state, DoS(100, false, REJECT_INVALID, "bad-txns-version-too-low", false, "")).Times(1);
     CheckTransactionWithoutProofVerification(tx, state);
 }
 
@@ -860,7 +863,7 @@ TEST(ChecktransactionTests, SaplingSproutInputSumsTooLarge) {
     {
         UNSAFE_CTransaction tx(mtx);
         MockCValidationState state;
-        EXPECT_CALL(state, DoS(100, false, REJECT_INVALID, "bad-txns-txintotal-toolarge", false)).Times(1);
+        EXPECT_CALL(state, DoS(100, false, REJECT_INVALID, "bad-txns-txintotal-toolarge", false, "")).Times(1);
         CheckTransactionWithoutProofVerification(tx, state);
     }
 }
@@ -877,7 +880,7 @@ TEST(ChecktransactionTests, OverwinterVersionNumberLow) {
     EXPECT_THROW((CTransaction(mtx)), std::ios_base::failure);
     UNSAFE_CTransaction tx(mtx);
     MockCValidationState state;
-    EXPECT_CALL(state, DoS(100, false, REJECT_INVALID, "bad-tx-overwinter-version-too-low", false)).Times(1);
+    EXPECT_CALL(state, DoS(100, false, REJECT_INVALID, "bad-tx-overwinter-version-too-low", false, "")).Times(1);
     CheckTransactionWithoutProofVerification(tx, state);
 }
 
@@ -896,7 +899,7 @@ TEST(ChecktransactionTests, OverwinterVersionNumberHigh) {
     EXPECT_THROW((CTransaction(mtx)), std::ios_base::failure);
     UNSAFE_CTransaction tx(mtx);
     MockCValidationState state;
-    EXPECT_CALL(state, DoS(100, false, REJECT_INVALID, "bad-tx-overwinter-version-too-high", false)).Times(1);
+    EXPECT_CALL(state, DoS(100, false, REJECT_INVALID, "bad-tx-overwinter-version-too-high", false, "")).Times(1);
     ContextualCheckTransaction(tx, state, Params(), 1, true);
 
     // Revert to default
@@ -916,7 +919,7 @@ TEST(ChecktransactionTests, OverwinterBadVersionGroupId) {
     EXPECT_THROW((CTransaction(mtx)), std::ios_base::failure);
     UNSAFE_CTransaction tx(mtx);
     MockCValidationState state;
-    EXPECT_CALL(state, DoS(100, false, REJECT_INVALID, "bad-tx-version-group-id", false)).Times(1);
+    EXPECT_CALL(state, DoS(100, false, REJECT_INVALID, "bad-tx-version-group-id", false, "")).Times(1);
     CheckTransactionWithoutProofVerification(tx, state);
 }
 
@@ -935,15 +938,15 @@ TEST(ChecktransactionTests, OverwinterNotActive) {
     MockCValidationState state;
     // during initial block download, for transactions being accepted into the
     // mempool (and thus not mined), DoS ban score should be zero, else 10
-    EXPECT_CALL(state, DoS(0, false, REJECT_INVALID, "tx-overwinter-not-active", false)).Times(1);
+    EXPECT_CALL(state, DoS(0, false, REJECT_INVALID, "tx-overwinter-not-active", false, "")).Times(1);
     ContextualCheckTransaction(tx, state, chainparams, 0, false, [](const Consensus::Params&) { return true; });
-    EXPECT_CALL(state, DoS(10, false, REJECT_INVALID, "tx-overwinter-not-active", false)).Times(1);
+    EXPECT_CALL(state, DoS(10, false, REJECT_INVALID, "tx-overwinter-not-active", false, "")).Times(1);
     ContextualCheckTransaction(tx, state, chainparams, 0, false, [](const Consensus::Params&) { return false; });
     // for transactions that have been mined in a block, DoS ban score should
     // always be 100.
-    EXPECT_CALL(state, DoS(100, false, REJECT_INVALID, "tx-overwinter-not-active", false)).Times(1);
+    EXPECT_CALL(state, DoS(100, false, REJECT_INVALID, "tx-overwinter-not-active", false, "")).Times(1);
     ContextualCheckTransaction(tx, state, chainparams, 0, true, [](const Consensus::Params&) { return true; });
-    EXPECT_CALL(state, DoS(100, false, REJECT_INVALID, "tx-overwinter-not-active", false)).Times(1);
+    EXPECT_CALL(state, DoS(100, false, REJECT_INVALID, "tx-overwinter-not-active", false, "")).Times(1);
     ContextualCheckTransaction(tx, state, chainparams, 0, true, [](const Consensus::Params&) { return false; });
 }
 
@@ -960,7 +963,7 @@ TEST(ChecktransactionTests, OverwinterFlagNotSet) {
 
     CTransaction tx(mtx);
     MockCValidationState state;
-    EXPECT_CALL(state, DoS(100, false, REJECT_INVALID, "tx-overwintered-flag-not-set", false)).Times(1);
+    EXPECT_CALL(state, DoS(100, false, REJECT_INVALID, "tx-overwintered-flag-not-set", false, "")).Times(1);
     ContextualCheckTransaction(tx, state, Params(), 1, true);
 
     // Revert to default
@@ -1125,13 +1128,13 @@ TEST(ChecktransactionTests, InvalidShieldedCoinbase) {
 
     // Before Heartwood, output descriptions are rejected.
     MockCValidationState state;
-    EXPECT_CALL(state, DoS(100, false, REJECT_INVALID, "bad-cb-has-output-description", false)).Times(1);
+    EXPECT_CALL(state, DoS(100, false, REJECT_INVALID, "bad-cb-has-output-description", false, "")).Times(1);
     ContextualCheckTransaction(tx, state, Params(), 10, 57);
 
     RegtestActivateHeartwood(false, Consensus::NetworkUpgrade::ALWAYS_ACTIVE);
 
     // From Heartwood, the output description is allowed but invalid (undecryptable).
-    EXPECT_CALL(state, DoS(100, false, REJECT_INVALID, "bad-cb-output-desc-invalid-outct", false)).Times(1);
+    EXPECT_CALL(state, DoS(100, false, REJECT_INVALID, "bad-cb-output-desc-invalid-outct", false, "")).Times(1);
     ContextualCheckTransaction(tx, state, Params(), 10, 57);
 
     RegtestDeactivateHeartwood();
@@ -1168,7 +1171,7 @@ TEST(ChecktransactionTests, HeartwoodAcceptsShieldedCoinbase) {
         EXPECT_TRUE(tx.IsCoinBase());
 
         MockCValidationState state;
-        EXPECT_CALL(state, DoS(100, false, REJECT_INVALID, "bad-cb-output-desc-invalid-outct", false)).Times(1);
+        EXPECT_CALL(state, DoS(100, false, REJECT_INVALID, "bad-cb-output-desc-invalid-outct", false, "")).Times(1);
         ContextualCheckTransaction(tx, state, chainparams, 10, 57);
 
         mtx.vShieldedOutput[0].cmu = cmOrig;
@@ -1182,7 +1185,7 @@ TEST(ChecktransactionTests, HeartwoodAcceptsShieldedCoinbase) {
         EXPECT_TRUE(tx.IsCoinBase());
 
         MockCValidationState state;
-        EXPECT_CALL(state, DoS(100, false, REJECT_INVALID, "bad-cb-output-desc-invalid-outct", false)).Times(1);
+        EXPECT_CALL(state, DoS(100, false, REJECT_INVALID, "bad-cb-output-desc-invalid-outct", false, "")).Times(1);
         ContextualCheckTransaction(tx, state, chainparams, 10, 57);
 
         mtx.vShieldedOutput[0].outCiphertext = outCtOrig;
@@ -1196,7 +1199,7 @@ TEST(ChecktransactionTests, HeartwoodAcceptsShieldedCoinbase) {
         EXPECT_TRUE(tx.IsCoinBase());
 
         MockCValidationState state;
-        EXPECT_CALL(state, DoS(100, false, REJECT_INVALID, "bad-cb-output-desc-invalid-encct", false)).Times(1);
+        EXPECT_CALL(state, DoS(100, false, REJECT_INVALID, "bad-cb-output-desc-invalid-encct", false, "")).Times(1);
         ContextualCheckTransaction(tx, state, chainparams, 10, 57);
 
         mtx.vShieldedOutput[0].encCiphertext = encCtOrig;
@@ -1210,7 +1213,7 @@ TEST(ChecktransactionTests, HeartwoodAcceptsShieldedCoinbase) {
         EXPECT_TRUE(tx.IsCoinBase());
 
         MockCValidationState state;
-        EXPECT_CALL(state, DoS(100, false, REJECT_INVALID, "bad-txns-sapling-binding-signature-invalid", false)).Times(1);
+        EXPECT_CALL(state, DoS(100, false, REJECT_INVALID, "bad-txns-sapling-binding-signature-invalid", false, "")).Times(1);
         ContextualCheckTransaction(tx, state, chainparams, 10, 57);
     }
 
@@ -1247,7 +1250,7 @@ TEST(ChecktransactionTests, HeartwoodEnforcesSaplingRulesOnShieldedCoinbase) {
         EXPECT_TRUE(tx.IsCoinBase());
 
         MockCValidationState state;
-        EXPECT_CALL(state, DoS(100, false, REJECT_INVALID, "bad-txns-valuebalance-nonzero", false)).Times(1);
+        EXPECT_CALL(state, DoS(100, false, REJECT_INVALID, "bad-txns-valuebalance-nonzero", false, "")).Times(1);
         EXPECT_FALSE(CheckTransactionWithoutProofVerification(tx, state));
     }
 
@@ -1266,7 +1269,7 @@ TEST(ChecktransactionTests, HeartwoodEnforcesSaplingRulesOnShieldedCoinbase) {
         EXPECT_TRUE(tx.IsCoinBase());
 
         MockCValidationState state;
-        EXPECT_CALL(state, DoS(100, false, REJECT_INVALID, "bad-txns-valuebalance-toolarge", false)).Times(1);
+        EXPECT_CALL(state, DoS(100, false, REJECT_INVALID, "bad-txns-valuebalance-toolarge", false, "")).Times(1);
         EXPECT_FALSE(CheckTransactionWithoutProofVerification(tx, state));
     }
     {
@@ -1276,7 +1279,7 @@ TEST(ChecktransactionTests, HeartwoodEnforcesSaplingRulesOnShieldedCoinbase) {
         EXPECT_TRUE(tx.IsCoinBase());
 
         MockCValidationState state;
-        EXPECT_CALL(state, DoS(100, false, REJECT_INVALID, "bad-txns-valuebalance-toolarge", false)).Times(1);
+        EXPECT_CALL(state, DoS(100, false, REJECT_INVALID, "bad-txns-valuebalance-toolarge", false, "")).Times(1);
         EXPECT_FALSE(CheckTransactionWithoutProofVerification(tx, state));
     }
 
@@ -1290,7 +1293,7 @@ TEST(ChecktransactionTests, HeartwoodEnforcesSaplingRulesOnShieldedCoinbase) {
 
     // Coinbase transaction does not pass contextual checks, as bindingSig
     // consensus rule is enforced.
-    EXPECT_CALL(state, DoS(100, false, REJECT_INVALID, "bad-txns-sapling-binding-signature-invalid", false)).Times(1);
+    EXPECT_CALL(state, DoS(100, false, REJECT_INVALID, "bad-txns-sapling-binding-signature-invalid", false, "")).Times(1);
     ContextualCheckTransaction(tx, state, chainparams, 10, 57);
 
     RegtestDeactivateHeartwood();
@@ -1320,7 +1323,7 @@ TEST(ChecktransactionTests, CanopyRejectsNonzeroVPubOld) {
 
     // After Canopy, nonzero vpub_old is accepted in non-contextual checks but rejected in contextual checks
     EXPECT_TRUE(CheckTransactionWithoutProofVerification(tx, state));
-    EXPECT_CALL(state, DoS(100, false, REJECT_INVALID, "bad-txns-vpub_old-nonzero", false)).Times(1);
+    EXPECT_CALL(state, DoS(100, false, REJECT_INVALID, "bad-txns-vpub_old-nonzero", false, "")).Times(1);
     EXPECT_FALSE(ContextualCheckTransaction(tx, state, Params(), 10, true));
 
     RegtestDeactivateCanopy();
diff --git a/src/gtest/test_validation.cpp b/src/gtest/test_validation.cpp
index 8e89b2b49..21833fb63 100644
--- a/src/gtest/test_validation.cpp
+++ b/src/gtest/test_validation.cpp
@@ -97,11 +97,13 @@ public:
 
 class MockCValidationState : public CValidationState {
 public:
-    MOCK_METHOD5(DoS, bool(int level, bool ret,
-             unsigned int chRejectCodeIn, std::string strRejectReasonIn,
-             bool corruptionIn));
-    MOCK_METHOD3(Invalid, bool(bool ret,
-                 unsigned int _chRejectCode, std::string _strRejectReason));
+    MOCK_METHOD6(DoS, bool(int level, bool ret,
+             unsigned int chRejectCodeIn, const std::string strRejectReasonIn,
+             bool corruptionIn,
+             const std::string &strDebugMessageIn));
+    MOCK_METHOD4(Invalid, bool(bool ret,
+                 unsigned int _chRejectCode, const std::string _strRejectReason,
+                 const std::string &_strDebugMessage));
     MOCK_METHOD1(Error, bool(std::string strRejectReasonIn));
     MOCK_CONST_METHOD0(IsValid, bool());
     MOCK_CONST_METHOD0(IsInvalid, bool());
@@ -110,6 +112,7 @@ public:
     MOCK_CONST_METHOD0(CorruptionPossible, bool());
     MOCK_CONST_METHOD0(GetRejectCode, unsigned int());
     MOCK_CONST_METHOD0(GetRejectReason, std::string());
+    MOCK_CONST_METHOD0(GetDebugMessage, std::string());
 };
 
 TEST(Validation, ContextualCheckInputsPassesWithCoinbase) {
@@ -190,7 +193,7 @@ TEST(Validation, ContextualCheckInputsDetectsOldBranchId) {
         strprintf("old-consensus-branch-id (Expected %s, found %s)",
             HexInt(saplingBranchId),
             HexInt(overwinterBranchId)),
-        false)).Times(1);
+        false, "")).Times(1);
     EXPECT_FALSE(ContextualCheckInputs(
         tx, mockState, view, true, 0, false, txdata,
         consensusParams, saplingBranchId));
@@ -201,7 +204,7 @@ TEST(Validation, ContextualCheckInputsDetectsOldBranchId) {
     EXPECT_CALL(mockState, DoS(
         100, false, REJECT_INVALID,
         "mandatory-script-verify-flag-failed (Script evaluated without error but finished with a false/empty top stack element)",
-        false)).Times(1);
+        false, "")).Times(1);
     EXPECT_FALSE(ContextualCheckInputs(
         tx, mockState, view, true, 0, false, txdata,
         consensusParams, blossomBranchId));