diff --git a/examples/example_transfer_transaction_bls.py b/examples/example_transfer_transaction_bls.py
index f03d86f..e590ee7 100644
--- a/examples/example_transfer_transaction_bls.py
+++ b/examples/example_transfer_transaction_bls.py
@@ -18,11 +18,16 @@ def main() -> None:
     sec = PrivateKey.from_string(
         "TSECRET1PZF33H72N9PHXZATY5URH5SS4M33VVDFAWYVESL5JTLT9A00TNWKQYNGM6Z"
     )
+    pub = sec.public_key()
 
     tx = Transaction.create_transfer_tx(lock_time, sender, receiver, amount, fee, memo)
-    signed_tx = tx.sign(sec)
+    signed_data = tx.sign(sec)
 
-    print(f"Signed transaction hex: {signed_tx.hex()}")
+    if not pub.verify(bytes(tx.sign_bytes()), tx.signature):
+        print("Signature verification failed")
+        exit(1)
+
+    print(f"Signed transaction hex: {signed_data.hex()}")
 
 
 if __name__ == "__main__":
diff --git a/examples/example_transfer_transaction_ed25519.py b/examples/example_transfer_transaction_ed25519.py
index f1c9d5a..f2b190b 100644
--- a/examples/example_transfer_transaction_ed25519.py
+++ b/examples/example_transfer_transaction_ed25519.py
@@ -18,10 +18,15 @@ def main() -> None:
     sec = PrivateKey.from_string(
         "TSECRET1RGLSGPYLQRVET27AZUVS9TSP8MPGF9LH4U4RKKARMCATFK9L0KUCS7DCC09"
     )
+    pub = sec.public_key()
 
     tx = Transaction.create_transfer_tx(lock_time, sender, receiver, amount, fee, memo)
     signed_tx = tx.sign(sec)
 
+    if not pub.verify(bytes(tx.sign_bytes()), tx.signature):
+        print("Signature verification failed")
+        exit(1)
+
     print(f"Signed transaction hex: {signed_tx.hex()}")
 
 
diff --git a/pactus/amount.py b/pactus/amount.py
index d7f492d..def8a40 100644
--- a/pactus/amount.py
+++ b/pactus/amount.py
@@ -26,6 +26,9 @@ def __eq__(self, other: "Amount") -> bool:
 
         return False
 
+    def __hash__(self) -> int:
+        return hash(self.value)
+
     @classmethod
     def from_nano_pac(cls, a: int) -> "Amount":
         """Store the value as NanoPAC in the Amount instance."""
diff --git a/pactus/transaction/transaction.py b/pactus/transaction/transaction.py
index 55e82fe..fba2459 100644
--- a/pactus/transaction/transaction.py
+++ b/pactus/transaction/transaction.py
@@ -1,6 +1,8 @@
 from pactus.amount import Amount
 from pactus.crypto.address import Address
 from pactus.crypto.private_key import PrivateKey
+from pactus.crypto.public_key import PublicKey
+from pactus.crypto.signature import Signature
 from pactus.encoding import encoding
 
 from ._payload import (
@@ -11,6 +13,9 @@
     WithdrawPayload,
 )
 
+FLAG_STRIPPED_PUBLIC_KEY = 0x01
+FLAG_NOT_SIGNED = 0x02
+
 
 class Transaction:
     def __init__(
@@ -26,6 +31,8 @@ def __init__(
         self.version = 1
         self.fee = fee
         self.payload = payload
+        self.public_key: PublicKey = None
+        self.signature: Signature = None
 
     @classmethod
     def create_transfer_tx(
@@ -129,4 +136,8 @@ def sign(self, private_key: PrivateKey) -> bytes:
         encoding.append_fixed_bytes(buf, sig.raw_bytes())
         encoding.append_fixed_bytes(buf, pub.raw_bytes())
 
+        self.public_key = pub
+        self.signature = sig
+        self.flags |= FLAG_NOT_SIGNED
+
         return buf
diff --git a/ruff.toml b/ruff.toml
index a0c12b8..f1755b6 100644
--- a/ruff.toml
+++ b/ruff.toml
@@ -51,6 +51,7 @@ ignore = [
     "D107",
     "D203",
     "D212",
+    "TC001",
     "COM812",
     "ISC001",
     "D205",