diff --git a/contracts/utils/FreezeLog.sol b/contracts/utils/FreezeLog.sol
new file mode 100644
index 0000000..d5a23b9
--- /dev/null
+++ b/contracts/utils/FreezeLog.sol
@@ -0,0 +1,114 @@
+/**
+ * Copyright BOOSTRY Co., Ltd.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ *
+ * You may obtain a copy of the License at
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+pragma solidity ^0.8.0;
+
+/// @title Freeze Log
+contract FreezeLog {
+    // Event: log recorded
+    event Recorded(
+        address indexed recorder,
+        uint256 index,
+        uint256 _freezingGraceBlockCount
+    );
+
+    // Event: log updated
+    event Updated(address indexed recorder, uint256 index);
+
+    struct Log {
+        address recorder; // Recorder
+        string log; // Log text
+        uint256 createdBlockNumber; // Created block number
+        uint256 freezingGraceBlockCount; // Freezing grace block count
+    }
+
+    /// Recorder -> Index
+    mapping(address => uint256) public last_log_index;
+    /// Recorder -> Index -> Log
+    mapping(address => mapping(uint256 => Log)) public logs;
+
+    // [CONSTRUCTOR]
+    constructor() {}
+
+    /// @notice Get last index
+    /// @param _recorder Recorder
+    /// @return _index Last index
+    function lastLogIndex(address _recorder)
+        public
+        view
+        returns (uint256 _index)
+    {
+        return last_log_index[_recorder];
+    }
+
+    /// @notice Record new logs
+    /// @param _log Log text
+    /// @param _freezingGraceBlockCount Freezing grace block count
+    function recordLog(string memory _log, uint256 _freezingGraceBlockCount)
+        public
+    {
+        Log storage log = logs[msg.sender][last_log_index[msg.sender]];
+
+        log.recorder = msg.sender;
+        log.log = _log;
+        log.createdBlockNumber = block.number;
+        log.freezingGraceBlockCount = _freezingGraceBlockCount;
+        last_log_index[msg.sender]++;
+
+        emit Recorded(
+            msg.sender,
+            last_log_index[msg.sender] - 1,
+            _freezingGraceBlockCount
+        );
+    }
+
+    /// @notice Update recorded logs
+    /// @param _index Index
+    /// @param _log Log to be updated
+    function updateLog(uint256 _index, string memory _log) public {
+        Log storage storageLog = logs[msg.sender][_index];
+
+        require(
+            storageLog.createdBlockNumber +
+                storageLog.freezingGraceBlockCount >=
+                block.number,
+            "frozen"
+        );
+
+        storageLog.log = _log;
+
+        emit Updated(msg.sender, _index);
+    }
+
+    /// @notice Get log
+    /// @param _recorder Recorder
+    /// @param _index Index
+    function getLog(address _recorder, uint256 _index)
+        public
+        view
+        returns (
+            uint256 _createdBlockNumber,
+            uint256 _freezingGraceBlockCount,
+            string memory _log
+        )
+    {
+        Log storage log = logs[_recorder][_index];
+        return (log.createdBlockNumber, log.freezingGraceBlockCount, log.log);
+    }
+}
diff --git a/tests/utils/test_FreezeLog.py b/tests/utils/test_FreezeLog.py
new file mode 100644
index 0000000..ca33b44
--- /dev/null
+++ b/tests/utils/test_FreezeLog.py
@@ -0,0 +1,252 @@
+"""
+Copyright BOOSTRY Co., Ltd.
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+http://www.apache.org/licenses/LICENSE-2.0
+Unless required by applicable law or agreed to in writing,
+software distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+SPDX-License-Identifier: Apache-2.0
+"""
+import brownie
+
+
+class TestRecordLog:
+
+    ##########################################################
+    # Normal
+    ##########################################################
+
+    # Normal_1
+    # Add a record once.
+    def test_normal_1(self, FreezeLog, users, web3):
+        admin = users["admin"]
+        user = users["user1"]
+
+        # Deploy contract
+        freeze_log = admin.deploy(FreezeLog)
+        test_block = web3.eth.block_number + 1
+        test_message = "test_message"
+        test_freezing_grace_block_count = 5
+
+        # Record Log
+        tx = freeze_log.recordLog(
+            test_message, test_freezing_grace_block_count, {"from": user}
+        )
+
+        # Assertion
+        assert tx.events["Recorded"]["recorder"] == user
+
+        log = freeze_log.getLog(user.address, 0, {"from": user})
+        assert log == (test_block, test_freezing_grace_block_count, test_message)
+
+    # Normal_2
+    # 2 person add a record each.
+    def test_normal_2(self, FreezeLog, users, web3):
+        admin = users["admin"]
+        user1 = users["user1"]
+        user2 = users["user2"]
+
+        # Deploy contract
+        freeze_log = admin.deploy(FreezeLog)
+        test_block = web3.eth.block_number + 1
+        test_message = "test_message"
+        test_freezing_grace_block_count = 5
+
+        # Record Log
+        tx = freeze_log.recordLog(
+            test_message, test_freezing_grace_block_count, {"from": user1}
+        )
+
+        # Assertion
+        assert tx.events["Recorded"]["recorder"] == user1.address
+        log = freeze_log.getLog(user1.address, 0, {"from": user1})
+        assert log == (test_block, test_freezing_grace_block_count, test_message)
+
+        # Deploy contract
+        freeze_log = admin.deploy(FreezeLog)
+        test_block = web3.eth.block_number + 1
+        test_message = "test_message"
+        test_freezing_grace_block_count = 5
+
+        # Record Log
+        tx = freeze_log.recordLog(
+            test_message, test_freezing_grace_block_count, {"from": user2}
+        )
+
+        # Assertion
+        assert tx.events["Recorded"]["recorder"] == user2.address
+        log = freeze_log.getLog(user2.address, 0, {"from": user2})
+        assert log == (test_block, test_freezing_grace_block_count, test_message)
+
+
+class TestLastLogIndex:
+
+    ##########################################################
+    # Normal
+    ##########################################################
+
+    # Normal_1
+    # Get last_log_index after adding a record.
+    def test_normal_1(self, FreezeLog, users, web3):
+        admin = users["admin"]
+        user1 = users["user1"]
+        user2 = users["user2"]
+        # Deploy contract
+        freeze_log = admin.deploy(FreezeLog)
+        test_block = web3.eth.block_number + 1
+        test_message = "test_message"
+        test_freezing_grace_block_count = 5
+
+        # Record Log
+        tx = freeze_log.recordLog(
+            test_message, test_freezing_grace_block_count, {"from": user1}
+        )
+
+        # get last_log_index of user1
+        user1_last_log_index = freeze_log.lastLogIndex(user1, {"from": user2})
+        assert user1_last_log_index == 1
+        # get last_log_index of user2
+        user2_last_log_index = freeze_log.lastLogIndex(user2, {"from": user2})
+        assert user2_last_log_index == 0
+
+
+class TestUpdateLog:
+
+    ##########################################################
+    # Normal
+    ##########################################################
+
+    # Normal_1
+    # After added a record, updating the record message.
+    def test_normal_1(self, FreezeLog, users, web3):
+        admin = users["admin"]
+        user = users["user1"]
+
+        # Deploy contract
+        freeze_log = admin.deploy(FreezeLog)
+        test_block = web3.eth.block_number + 1
+        test_message = "test_message"
+        test_freezing_grace_block_count = 5
+
+        # Record Log
+        tx = freeze_log.recordLog(
+            test_message, test_freezing_grace_block_count, {"from": user}
+        )
+        # Assertion
+        assert tx.events["Recorded"]["recorder"] == user
+
+        user_last_log_index = freeze_log.lastLogIndex(user, {"from": user})
+
+        tx = freeze_log.updateLog(
+            user_last_log_index - 1, test_message[::-1], {"from": user}
+        )
+
+        # Assertion
+        assert tx.events["Updated"]["recorder"] == user
+        assert tx.events["Updated"]["index"] == user_last_log_index - 1
+
+        log = freeze_log.getLog(user.address, user_last_log_index - 1, {"from": user})
+        assert log[0] == test_block
+        assert log[1] == test_freezing_grace_block_count
+        assert log[2] == test_message[::-1]
+
+    ##########################################################
+    # Error
+    ##########################################################
+
+    # Error_1
+    # Trying to update log of non-existent index, but fail.
+    def test_error_1(self, FreezeLog, users, web3):
+        admin = users["admin"]
+        user1 = users["user1"]
+
+        # Deploy contract
+        freeze_log = admin.deploy(FreezeLog)
+
+        test_idx = 10
+        test_message = "test1 message"
+        with brownie.reverts():
+            freeze_log.updateLog(test_idx, test_message, {"from": user1})
+        log = freeze_log.getLog(user1.address, 0, {"from": user1})
+        assert log == (0, 0, "")
+
+    # Error_2
+    # Trying to update a frozen log, but fail.
+    def test_error_2(self, FreezeLog, users, web3):
+        admin = users["admin"]
+        user1 = users["user1"]
+
+        # Deploy contract
+        freeze_log = admin.deploy(FreezeLog)
+
+        test1_block = web3.eth.block_number + 1
+        test1_message = "test1 message"
+        test1_freezing_grace_block_count = 2
+
+        # Write Log
+        tx1 = freeze_log.recordLog(
+            test1_message, test1_freezing_grace_block_count, {"from": user1}
+        )
+        log = freeze_log.getLog(user1.address, 0, {"from": user1})
+
+        # Assertion
+        assert tx1.events["Recorded"]["recorder"] == user1.address
+        assert log[0] == test1_block
+        assert log[1] == test1_freezing_grace_block_count
+        assert log[2] == test1_message
+
+        # Add logs to freeze first log.
+        for i in range(test1_freezing_grace_block_count):
+            tx1 = freeze_log.recordLog(
+                test1_message, test1_freezing_grace_block_count, {"from": user1}
+            )
+
+        # Trying to update a frozen log.
+        with brownie.reverts(revert_msg="frozen"):
+            test1_message_update = "test1 message updated"
+            freeze_log.updateLog(0, test1_message_update, {"from": user1})
+
+        log = freeze_log.getLog(user1.address, 0, {"from": user1})
+        assert log[0] == test1_block
+        assert log[1] == test1_freezing_grace_block_count
+        assert log[2] == test1_message
+
+
+class TestGetLog:
+
+    ##########################################################
+    # Normal
+    ##########################################################
+
+    # Normal_1
+    # Get a log record by index.
+    def test_normal_1(self, FreezeLog, users, web3):
+        admin = users["admin"]
+        user1 = users["user1"]
+
+        # Deploy contract
+        freeze_log = admin.deploy(FreezeLog)
+        test1_block = web3.eth.block_number + 1
+        test1_message = "test1 message"
+        test1_freezing_grace_block_count = 1
+
+        # Write Log
+        tx = freeze_log.recordLog(
+            test1_message, test1_freezing_grace_block_count, {"from": user1}
+        )
+
+        # Assertion
+        assert tx.events["Recorded"]["recorder"] == user1.address
+
+        user1_last_log_index = freeze_log.lastLogIndex(user1.address)
+
+        log = freeze_log.getLog(
+            user1.address, user1_last_log_index - 1, {"from": user1}
+        )
+        assert log[0] == test1_block
+        assert log[1] == test1_freezing_grace_block_count
+        assert log[2] == test1_message