diff --git a/packages/kos-web/src/wallet.rs b/packages/kos-web/src/wallet.rs
index 9812a59..4bb3588 100644
--- a/packages/kos-web/src/wallet.rs
+++ b/packages/kos-web/src/wallet.rs
@@ -487,4 +487,21 @@ mod tests {
         let message = b"test message";
         assert!(wallet.sign_message(message).is_err());
     }
+
+    #[test]
+    fn test_sign_transaction() {
+        let chain_id = 38;
+        let chain = get_chain_by_base_id(chain_id).unwrap();
+        let path = chain.get_path(0, false);
+
+        let wallet =
+            Wallet::from_mnemonic(chain_id, TEST_MNEMONIC.to_string(), path, None).unwrap();
+
+        let tx_raw = r#"{"RawData":{"Sender":"UMjR49Dkn+HleedQY88TSjXXJhtbDpX7f7QVF/Dcqos=","Contract":[{"Type":63,"Parameter":{"type_url":"type.googleapis.com/proto.SmartContract","value":"EiAAAAAAAAAAAAUAIPnuq04LIuz1ew83LbqEVgLiyNyybBoRCghGUkctMlZCVRIFCIDh6xc="}}],"Data":["c3Rha2VGYXJt"],"KAppFee":2000000,"BandwidthFee":4622449,"Version":1,"ChainID":"MTAwMDAx"}}"#;
+
+        let signed_tx = wallet.sign(tx_raw.as_bytes(), None).unwrap();
+
+        assert!(!signed_tx.signature.is_empty());
+        assert!(!signed_tx.tx_hash.is_empty());
+    }
 }
diff --git a/packages/kos/src/chains/klv/mod.rs b/packages/kos/src/chains/klv/mod.rs
index 71daeb0..034d87f 100644
--- a/packages/kos/src/chains/klv/mod.rs
+++ b/packages/kos/src/chains/klv/mod.rs
@@ -285,6 +285,31 @@ mod test {
         );
     }
 
+    #[test]
+    fn test_sign_tx_4() {
+        let pvk = hex::decode("1ab42cc412b618bdea3a599e3c9bae199ebf030895b039e9db1e30dafb12b727")
+            .unwrap();
+
+        let json = r#"{"RawData":{"Sender":"UMjR49Dkn+HleedQY88TSjXXJhtbDpX7f7QVF/Dcqos=","Contract":[{"Type":63,"Parameter":{"type_url":"type.googleapis.com/proto.SmartContract","value":"EiAAAAAAAAAAAAUAIPnuq04LIuz1ew83LbqEVgLiyNyybBoRCghGUkctMlZCVRIFCIDh6xc="}}],"Data":["c3Rha2VGYXJt"],"KAppFee":2000000,"BandwidthFee":4622449,"Version":1,"ChainID":"MTAwMDAx"}}"#;
+
+        let raw_tx = json.as_bytes().to_vec();
+
+        let tx = crate::chains::Transaction {
+            raw_data: raw_tx,
+            tx_hash: Vec::new(),
+            signature: Vec::new(),
+            options: None,
+        };
+
+        let result_tx = crate::chains::klv::KLV {}.sign_tx(pvk, tx).unwrap();
+
+        assert_eq!(
+            result_tx.tx_hash,
+            hex::decode("50fce82cb3f4bf851d86fd594133b13e891d1f565958b0a95b11ce47f2179926")
+                .unwrap()
+        );
+    }
+
     #[test]
     fn test_decode_klv_tx() {
         let raw_tx = hex::decode(
diff --git a/packages/kos/src/chains/klv/models.rs b/packages/kos/src/chains/klv/models.rs
index e09e819..f52a037 100644
--- a/packages/kos/src/chains/klv/models.rs
+++ b/packages/kos/src/chains/klv/models.rs
@@ -33,7 +33,7 @@ pub struct Transaction {
 #[derive(Clone, PartialEq, Serialize, Deserialize)]
 pub struct Raw {
     #[Rename = "Nonce"]
-    pub nonce: u64,
+    pub nonce: Option<u64>,
     #[Rename = "Sender"]
     pub sender: String,
     #[Rename = "Contract"]
@@ -151,7 +151,7 @@ impl TryFrom<chains::klv::models::Raw> for proto::transaction::Raw {
             .collect::<Result<Vec<_>, _>>()?;
 
         let proto_raw = proto::transaction::Raw {
-            nonce: value.nonce,
+            nonce: value.nonce.unwrap_or(0),
             sender: simple_base64_decode(&value.sender)
                 .map_err(|_| ConversionError::Base64Error)?,
             contract: contracts,
diff --git a/packages/kos/src/protos/generated/klv/proto.rs b/packages/kos/src/protos/generated/klv/proto.rs
index d480efe..1402644 100644
--- a/packages/kos/src/protos/generated/klv/proto.rs
+++ b/packages/kos/src/protos/generated/klv/proto.rs
@@ -1184,6 +1184,7 @@ pub mod tx_contract {
         UpdateAccountPermissionContractType = 22,
         DepositContractType = 23,
         ItoTriggerContractType = 24,
+        SmartContractType = 63,
     }
     impl ContractType {
         /// String value of the enum field names used in the ProtoBuf definition.
@@ -1229,6 +1230,7 @@ pub mod tx_contract {
                 }
                 ContractType::DepositContractType => "DepositContractType",
                 ContractType::ItoTriggerContractType => "ITOTriggerContractType",
+                ContractType::SmartContractType => "SmartContractType",
             }
         }
         /// Creates an enum from field names used in the ProtoBuf definition.
@@ -1267,6 +1269,7 @@ pub mod tx_contract {
                 }
                 "DepositContractType" => Some(Self::DepositContractType),
                 "ITOTriggerContractType" => Some(Self::ItoTriggerContractType),
+                "SmartContractType" => Some(Self::SmartContractType),
                 _ => None,
             }
         }
diff --git a/packages/kos/src/protos/klever/transaction.proto b/packages/kos/src/protos/klever/transaction.proto
index cb3267d..8b22437 100644
--- a/packages/kos/src/protos/klever/transaction.proto
+++ b/packages/kos/src/protos/klever/transaction.proto
@@ -34,6 +34,7 @@ message TXContract {
     UpdateAccountPermissionContractType   = 22;
     DepositContractType                   = 23;
     ITOTriggerContractType                = 24;
+    SmartContractType                     = 63;
   }
   ContractType Type 				= 1 [json_name = "Type"];
   google.protobuf.Any Parameter 	= 2 [json_name = "Parameter"];