diff --git a/TransactionTests.md b/TransactionTests.md
index 5c32de278..466039e69 100644
--- a/TransactionTests.md
+++ b/TransactionTests.md
@@ -24,15 +24,15 @@ OK: 8/8 Fail: 0/8 Skip: 0/8
 ```diff
 + NotEnoughGasLimit.json                                          OK
 + TransactionWithGasLimitOverflow.json                            OK
-+ TransactionWithGasLimitOverflow2.json                           OK
-+ TransactionWithGasLimitOverflow63.json                          OK
-+ TransactionWithGasLimitOverflow63_1.json                        OK
+- TransactionWithGasLimitOverflow2.json                           Fail
+- TransactionWithGasLimitOverflow63.json                          Fail
+- TransactionWithGasLimitOverflow63_1.json                        Fail
 + TransactionWithGasLimitxPriceOverflow.json                      OK
 + TransactionWithGasLimitxPriceOverflow2.json                     OK
 + TransactionWithHighGas.json                                     OK
 + TransactionWithHihghGasLimit63m1.json                           OK
 ```
-OK: 9/9 Fail: 0/9 Skip: 0/9
+OK: 6/9 Fail: 3/9 Skip: 0/9
 ## ttGasPrice
 ```diff
 + TransactionWithGasPriceOverflow.json                            OK
@@ -221,4 +221,4 @@ OK: 2/2 Fail: 0/2 Skip: 0/2
 OK: 70/70 Fail: 0/70 Skip: 0/70
 
 ---TOTAL---
-OK: 179/179 Fail: 0/179 Skip: 0/179
+OK: 176/179 Fail: 3/179 Skip: 0/179
diff --git a/nimbus/transaction.nim b/nimbus/transaction.nim
index 64da542e4..f72eb62b6 100644
--- a/nimbus/transaction.nim
+++ b/nimbus/transaction.nim
@@ -29,13 +29,6 @@ proc intrinsicGas*(tx: Transaction, fork: Fork): GasInt =
   if tx.isContractCreation:
     result = result + gasFees[fork][GasTXCreate]
 
-proc validate*(t: Transaction, fork: Fork) =
-  # Hook called during instantiation to ensure that all transaction
-  # parameters pass validation rules
-  if t.intrinsicGas(fork) > t.gasLimit:
-    raise newException(ValidationError, "Insufficient gas")
-  #  self.check_signature_validity()
-
 proc getSignature*(transaction: Transaction, output: var Signature): bool =
   var bytes: array[65, byte]
   bytes[0..31] = transaction.R.toByteArrayBE()
@@ -55,7 +48,7 @@ proc getSignature*(transaction: Transaction, output: var Signature): bool =
 
 proc toSignature*(transaction: Transaction): Signature =
   if not getSignature(transaction, result):
-    raise newException(Exception, "Invalid signaure")
+    raise newException(Exception, "Invalid signature")
 
 proc getSender*(transaction: Transaction, output: var EthAddress): bool =
   ## Find the address the transaction was sent from.
@@ -78,3 +71,15 @@ proc getRecipient*(tx: Transaction): EthAddress =
     result = generateAddress(sender, tx.accountNonce)
   else:
     result = tx.to
+
+proc validate*(tx: Transaction, fork: Fork) =
+  # Hook called during instantiation to ensure that all transaction
+  # parameters pass validation rules
+  if tx.intrinsicGas(fork) > tx.gasLimit:
+    raise newException(ValidationError, "Insufficient gas")
+
+  # check signature validity
+  var sender: EthAddress
+  if not tx.getSender(sender):
+    raise newException(ValidationError, "Invalid signature or failed message verification")
+
diff --git a/tests/all_tests.nim b/tests/all_tests.nim
index dbe1821a7..7ad99f87c 100644
--- a/tests/all_tests.nim
+++ b/tests/all_tests.nim
@@ -23,5 +23,6 @@ import  ./test_code_stream,
         ./test_op_misc,
         ./test_op_custom,
         ./test_state_db,
-        ./test_difficulty
+        ./test_difficulty,
+        ./test_transaction_json