diff --git a/src/hiero_sdk_python/nodes/node_create_transaction.py b/src/hiero_sdk_python/nodes/node_create_transaction.py
index 472d08c25..58fd99e9f 100644
--- a/src/hiero_sdk_python/nodes/node_create_transaction.py
+++ b/src/hiero_sdk_python/nodes/node_create_transaction.py
@@ -7,7 +7,7 @@
 from hiero_sdk_python.account.account_id import AccountId
 from hiero_sdk_python.address_book.endpoint import Endpoint
 from hiero_sdk_python.channels import _Channel
-from hiero_sdk_python.crypto.public_key import PublicKey
+from hiero_sdk_python.crypto.key import Key
 from hiero_sdk_python.executable import _Method
 from hiero_sdk_python.hapi.services.node_create_pb2 import NodeCreateTransactionBody
 from hiero_sdk_python.hapi.services.schedulable_transaction_body_pb2 import (
@@ -29,7 +29,7 @@ class NodeCreateParams:
         service_endpoints (list[Endpoint]): The service endpoints of the node.
         gossip_ca_certificate (bytes, optional): The gossip ca certificate of the node.
         grpc_certificate_hash (bytes, optional): The grpc certificate hash of the node.
-        admin_key (PublicKey, optional): The admin key of the node.
+        admin_key (Key, optional): The admin key of the node.
         decline_reward (bool, optional): The decline reward of the node.
         grpc_web_proxy_endpoint (Endpoint, optional): The grpc web proxy endpoint of the node.
     """
@@ -40,7 +40,7 @@ class NodeCreateParams:
     service_endpoints: list[Endpoint] = field(default_factory=list)
     gossip_ca_certificate: bytes | None = None
     grpc_certificate_hash: bytes | None = None
-    admin_key: PublicKey | None = None
+    admin_key: Key | None = None
     decline_reward: bool | None = None
     grpc_web_proxy_endpoint: Endpoint | None = None
     associated_registered_nodes: list[int] = field(default_factory=list)
@@ -73,7 +73,7 @@ def __init__(self, node_create_params: NodeCreateParams | None = None):
         self.service_endpoints: list[Endpoint] = node_create_params.service_endpoints
         self.gossip_ca_certificate: bytes | None = node_create_params.gossip_ca_certificate
         self.grpc_certificate_hash: bytes | None = node_create_params.grpc_certificate_hash
-        self.admin_key: PublicKey | None = node_create_params.admin_key
+        self.admin_key: Key | None = node_create_params.admin_key
         self.decline_reward: bool | None = node_create_params.decline_reward
         self.grpc_web_proxy_endpoint: Endpoint | None = node_create_params.grpc_web_proxy_endpoint
         self.associated_registered_nodes: list[int] = node_create_params.associated_registered_nodes
@@ -168,12 +168,12 @@ def set_grpc_certificate_hash(self, grpc_certificate_hash: bytes | None) -> Node
         self.grpc_certificate_hash = grpc_certificate_hash
         return self
 
-    def set_admin_key(self, admin_key: PublicKey | None) -> NodeCreateTransaction:
+    def set_admin_key(self, admin_key: Key | None) -> NodeCreateTransaction:
         """
         Sets the admin key for this node create transaction.
 
         Args:
-            admin_key (PublicKey):
+            admin_key (Key):
                 The admin key of the node.
 
         Returns:
@@ -255,7 +255,7 @@ def _build_proto_body(self) -> NodeCreateTransactionBody:
             service_endpoint=[endpoint._to_proto() for endpoint in self.service_endpoints or []],
             gossip_ca_certificate=self.gossip_ca_certificate,
             grpc_certificate_hash=self.grpc_certificate_hash,
-            admin_key=self.admin_key._to_proto() if self.admin_key else None,
+            admin_key=self.admin_key.to_proto_key() if self.admin_key else None,
             decline_reward=self.decline_reward,
             grpc_proxy_endpoint=(self.grpc_web_proxy_endpoint._to_proto() if self.grpc_web_proxy_endpoint else None),
             associated_registered_node=self.associated_registered_nodes,
@@ -317,7 +317,7 @@ def _from_protobuf(cls, transaction_body, body_bytes: bytes, sig_map):
             if pb.grpc_certificate_hash:
                 transaction.grpc_certificate_hash = pb.grpc_certificate_hash
             if pb.HasField("admin_key"):
-                transaction.admin_key = PublicKey._from_proto(pb.admin_key)
+                transaction.admin_key = Key.from_proto_key(pb.admin_key)
             if pb.decline_reward:
                 transaction.decline_reward = pb.decline_reward
             if pb.HasField("grpc_proxy_endpoint"):
diff --git a/src/hiero_sdk_python/nodes/node_update_transaction.py b/src/hiero_sdk_python/nodes/node_update_transaction.py
index 92d2d81ac..ecb14e30b 100644
--- a/src/hiero_sdk_python/nodes/node_update_transaction.py
+++ b/src/hiero_sdk_python/nodes/node_update_transaction.py
@@ -10,7 +10,7 @@
 from hiero_sdk_python.account.account_id import AccountId
 from hiero_sdk_python.address_book.endpoint import Endpoint
 from hiero_sdk_python.channels import _Channel
-from hiero_sdk_python.crypto.public_key import PublicKey
+from hiero_sdk_python.crypto.key import Key
 from hiero_sdk_python.executable import _Method
 from hiero_sdk_python.hapi.services.node_update_pb2 import (
     AssociatedRegisteredNodeList,
@@ -36,7 +36,7 @@ class NodeUpdateParams:
         service_endpoints (list[Endpoint]): The service endpoints of the node.
         gossip_ca_certificate (bytes, None): The gossip ca certificate of the node.
         grpc_certificate_hash (bytes, None): The grpc certificate hash of the node.
-        admin_key (PublicKey, optional): The admin key of the node.
+        admin_key (Key, optional): The admin key of the node.
         decline_reward (bool, optional): The decline reward of the node.
         grpc_web_proxy_endpoint (Endpoint, optional): The grpc web proxy endpoint of the node.
     """
@@ -48,7 +48,7 @@ class NodeUpdateParams:
     service_endpoints: list[Endpoint] = field(default_factory=list)
     gossip_ca_certificate: bytes | None = None
     grpc_certificate_hash: bytes | None = None
-    admin_key: PublicKey | None = None
+    admin_key: Key | None = None
     decline_reward: bool | None = None
     grpc_web_proxy_endpoint: Endpoint | None = None
     associated_registered_nodes: list[int] | None = None
@@ -82,7 +82,7 @@ def __init__(self, node_update_params: NodeUpdateParams | None = None):
         self.service_endpoints: list[Endpoint] = node_update_params.service_endpoints
         self.gossip_ca_certificate: bytes | None = node_update_params.gossip_ca_certificate
         self.grpc_certificate_hash: bytes | None = node_update_params.grpc_certificate_hash
-        self.admin_key: PublicKey | None = node_update_params.admin_key
+        self.admin_key: Key | None = node_update_params.admin_key
         self.decline_reward: bool | None = node_update_params.decline_reward
         self.grpc_web_proxy_endpoint: Endpoint | None = node_update_params.grpc_web_proxy_endpoint
         self.associated_registered_nodes: list[int] | None = node_update_params.associated_registered_nodes
@@ -192,12 +192,12 @@ def set_grpc_certificate_hash(self, grpc_certificate_hash: bytes | None) -> Node
         self.grpc_certificate_hash = grpc_certificate_hash
         return self
 
-    def set_admin_key(self, admin_key: PublicKey | None) -> NodeUpdateTransaction:
+    def set_admin_key(self, admin_key: Key | None) -> NodeUpdateTransaction:
         """
         Sets the admin key for this node update transaction.
 
         Args:
-            admin_key (PublicKey):
+            admin_key (Key):
                 The admin key of the node.
 
         Returns:
@@ -306,7 +306,7 @@ def _build_proto_body(self) -> NodeUpdateTransactionBody:
             grpc_certificate_hash=(
                 BytesValue(value=self.grpc_certificate_hash) if self.grpc_certificate_hash is not None else None
             ),
-            admin_key=self._convert_to_proto(self.admin_key),
+            admin_key=self.admin_key.to_proto_key() if self.admin_key else None,
             decline_reward=(BoolValue(value=self.decline_reward) if self.decline_reward is not None else None),
             grpc_proxy_endpoint=self._convert_to_proto(self.grpc_web_proxy_endpoint),
         )
@@ -377,7 +377,7 @@ def _from_protobuf(cls, transaction_body, body_bytes: bytes, sig_map):
             if pb.HasField("grpc_certificate_hash"):
                 transaction.grpc_certificate_hash = pb.grpc_certificate_hash.value
             if pb.HasField("admin_key"):
-                transaction.admin_key = PublicKey._from_proto(pb.admin_key)
+                transaction.admin_key = Key.from_proto_key(pb.admin_key)
             if pb.HasField("decline_reward"):
                 transaction.decline_reward = pb.decline_reward.value
             if pb.HasField("grpc_proxy_endpoint"):
diff --git a/tests/unit/node_create_transaction_test.py b/tests/unit/node_create_transaction_test.py
index 6c768d346..19fa16987 100644
--- a/tests/unit/node_create_transaction_test.py
+++ b/tests/unit/node_create_transaction_test.py
@@ -14,6 +14,7 @@
 from hiero_sdk_python.hapi.services.schedulable_transaction_body_pb2 import (
     SchedulableTransactionBody,
 )
+from hiero_sdk_python.hapi.services.transaction_pb2 import TransactionBody
 from hiero_sdk_python.nodes.node_create_transaction import (
     NodeCreateParams,
     NodeCreateTransaction,
@@ -330,3 +331,36 @@ def test_to_proto(mock_client):
 
     assert proto.signedTransactionBytes
     assert len(proto.signedTransactionBytes) > 0
+
+
+def test_node_create_transaction_build_with_private_key():
+    """NodeCreateTransaction should accept PrivateKey and serialize the PublicKey in the proto."""
+    private_key = PrivateKey.generate()
+    public_key = private_key.public_key()
+
+    tx = NodeCreateTransaction().set_admin_key(private_key)
+
+    body = tx._build_proto_body()
+
+    # In the proto we should have the public key not the private one
+    assert body.admin_key.ed25519 == public_key.to_bytes_raw()
+
+
+def test_node_create_transaction_from_protobuf_with_admin_key():
+    """NodeCreateTransaction should deserialize the admin_key from the proto correctly."""
+    private_key = PrivateKey.generate()
+
+    transaction = NodeCreateTransaction().set_admin_key(private_key)
+    body = transaction._build_proto_body()
+
+    transaction_body = TransactionBody()
+    transaction_body.nodeCreate.CopyFrom(body)
+
+    parsed_transaction = NodeCreateTransaction._from_protobuf(
+        transaction_body,
+        b"",
+        None,
+    )
+
+    assert parsed_transaction.admin_key is not None
+    assert parsed_transaction.admin_key.to_proto_key() == body.admin_key
diff --git a/tests/unit/node_update_transaction_test.py b/tests/unit/node_update_transaction_test.py
index b5bc95a43..a2e1c0f72 100644
--- a/tests/unit/node_update_transaction_test.py
+++ b/tests/unit/node_update_transaction_test.py
@@ -14,6 +14,7 @@
 from hiero_sdk_python.hapi.services.schedulable_transaction_body_pb2 import (
     SchedulableTransactionBody,
 )
+from hiero_sdk_python.hapi.services.transaction_pb2 import TransactionBody
 from hiero_sdk_python.nodes.node_update_transaction import (
     NodeUpdateParams,
     NodeUpdateTransaction,
@@ -351,3 +352,36 @@ def test_to_proto(mock_client):
 
     assert proto.signedTransactionBytes
     assert len(proto.signedTransactionBytes) > 0
+
+
+def test_node_update_transaction_build_with_private_key():
+    """NodeUpdateTransaction should accept PrivateKey and serialize the PublicKey in the proto."""
+    private_key = PrivateKey.generate()
+    public_key = private_key.public_key()
+
+    tx = NodeUpdateTransaction().set_admin_key(private_key)
+
+    body = tx._build_proto_body()
+
+    # In the proto we should have the public key not the private one
+    assert body.admin_key.ed25519 == public_key.to_bytes_raw()
+
+
+def test_node_update_transaction_from_protobuf_with_admin_key():
+    """NodeUpdateTransaction should deserialize the admin_key from the proto correctly."""
+    private_key = PrivateKey.generate()
+
+    transaction = NodeUpdateTransaction().set_admin_key(private_key)
+    body = transaction._build_proto_body()
+
+    transaction_body = TransactionBody()
+    transaction_body.nodeUpdate.CopyFrom(body)
+
+    parsed_transaction = NodeUpdateTransaction._from_protobuf(
+        transaction_body,
+        b"",
+        None,
+    )
+
+    assert parsed_transaction.admin_key is not None
+    assert parsed_transaction.admin_key.to_proto_key() == body.admin_key