TDE in SQL Server

Outline of the Article:

1. Introduction

2. How does SQL Server 2019's TDE work?

3. Benefits and Drawbacks of TDE

4. Implementation of TDE in SQL Server 2019

5. Obtaining Permission to Use TDE

6. TDE in SQL Server 2019 Implementation

7. How to remove TDE from a user database

7. Concluding

9. FAQs

Introduction of TDE

Any database management system must prioritize data protection. Transparent Data Encryption (TDE), a potent feature in SQL Server 2019, enhances data security by encrypting database files while they are at rest. This article will examine TDE in SQL Server 2019, go through its benefits and drawbacks, usage situations, the authorization needed to utilize it, and installation methods, give examples, and emphasize its importance in protecting sensitive data.

We can not encrypt system databases (Master, Model, and MSDB) using TDE is not accessible

TempDB is automatically encrypted when we enable TDE for a user database. Although it cannot be explicitly encrypted, tempdb is automatically encrypted when a user database enables TDE.

TDE performs real-time I/O data and log file encryption and decryption. 

TDE in SQL Server 2019: What Is It?

The Transparent Data Encryption (TDE) feature in SQL Server 2019 makes it possible for the database files to be automatically encrypted while they are at rest. TDE functions at the database level, encrypting the data pages before writing them to disc and decrypting them upon reading them into memory. This procedure makes sure that the data stays encrypted while being kept on the disc, reducing the possibility of sensitive material being accessed by unauthorized parties.

Benefits and Drawbacks of TDE:

TDE Enhanced Data Protection's benefits include: By protecting the database files from unauthorized access in the event of physical theft or unauthorized file system access, TDE adds an extra layer of protection.

Transparent Encryption: TDE requires no modifications to the application code or database queries because the encryption and decryption procedures are handled automatically by SQL Server. It is simpler to develop and maintain because of this seamless connectivity.

Compliance standards: TDE provides encryption at rest, which is frequently a required security safeguard for sensitive data, to assist organizations in complying with compliance standards.

Disadvantages of TDE:

TDE's drawbacks in terms of performance effect include that the encryption and decryption procedures add overhead to database operations, which might affect system performance as a whole. The effect can be reduced, though, with newer technology and optimized organization setups.

Limited Security Scope: TDE provides data encryption for data in memory, but not for data in transit or while it is protected at rest. To provide end-to-end data protection, further security measures should be applied, such as SSL/TLS for data in transit.

TDE implementation in SQL Server 2019

TDE is frequently used to safeguard private information kept in databases. It is especially helpful when databases are backed up or kept on portable media, both of which increase the risk of unauthorized access to the database files. TDE may be used in a variety of fields and sectors, including e-commerce, healthcare, banking, and other settings where data security is crucial.

Required Permission to Use of TDE:

The aforementioned permissions are necessary for TDE implementation and usage in SQL Server 2019:

Users must be granted CONTROL permission on the database to enable and control TDE.

Users must have access to DEFINITION permission on the database to access the encrypted state of the database.

How to Use TDE in 2019's SQL Server

The following actions are required to implement TDE in SQL Server 2019:

Make a master key: The database encryption key is encrypted using the master key. At the master database level, it is generated.

Create a certificate or receive one: The database encryption key is protected by the certificate. You may either construct it yourself in SQL Server or buy it from a reliable certificate authority (CA).

Make a key for database encryption: The master key is used to encrypt the database encryption key, which is then secured by the certificate.

Switch on TDE for the database: TDE may be activated on the database after the creation of the master key, certificate, and database encryption key.

The SQL Server manual contains comprehensive implementation instructions.

Step-By-Step Guide to Creating TDE in SQL Server:-

Step 1: Connect the server on which we want to implement the TDE

Step 2: Go to the Master database.

USE master;

GO

Step 3: Now we need to create a Master Key with a Strong Password. Keep the password in a safer place for future reference.

CREATE MASTER KEY ENCRYPTION BY PASSWORD = '<Use Strong Password >';

GO

For Example:-

CREATE MASTER KEY ENCRYPTION BY PASSWORD = 'Sh^4Ndv@1u9%b##bBJ';

GO

Step 3: Now create a certificate that we'll use at the time of database encryption key creation.

CREATE CERTIFICATE TDECertForDBServer WITH SUBJECT = 

'TDECertForDBServerDEKCertificate';

GO

Step 4: Now we need to create a database encryption key.

USE AdventureWorks2019;

GO

CREATE DATABASE ENCRYPTION KEY

WITH ALGORITHM = AES_256

ENCRYPTION BY SERVER CERTIFICATE TDECertForDBServer;

GO

Step 5: Now we set the encryption key with Database.

ALTER DATABASE AdventureWorks2019 SET ENCRYPTION ON;

GO

To check whether TDE is enabled or not for a database:

SELECT @@SERVERNAME AS ServerName,@@Version AS VERSION,

DB_Name(Database_ID) AS DatabaseName,create_date AS CreationDate,

key_algorithm AS UsedAlgorithm, key_length AS KeyLength,

(CASE Encryption_State WHEN 0 THEN 'No database encryption key present, no encryption'

 WHEN 1 THEN 'Unencrypted'

 WHEN 2 THEN 'Encryption in progress'

 WHEN 3 THEN 'Encrypted'

 WHEN 4 THEN 'Key change in progress'

 WHEN 5 THEN 'Decryption in progress'

 WHEN 6 THEN 'Protection change in progress'

 END) AS DatabaseEncryptionState

FROM sys.dm_database_encryption_keys

How to remove TDE from a user database

To remove TDE from a user database, we need to follow below steps:

1. Connect the server on which we need to remove TDE

2. Open new query windows & run the below command to remove TDE from the user database.

ALTER DATABASE [AdventureWorks2019] SET ENCRYPTION OFF;

3. The above command will start the decryption process & it'll take time depending on the size of the database & also available resources.

4. To monitor the progress of the above command, we can use the below query:

SELECT Database_ID as DatabaseID, DB_Name(Database_ID) AS DatabaseName,

(CASE Encryption_State WHEN 0 THEN 'No database encryption key present, no encryption'

 WHEN 1 THEN 'Unencrypted'

 WHEN 2 THEN 'Encryption in progress'

 WHEN 3 THEN 'Encrypted'

 WHEN 4 THEN 'Key change in progress'

 WHEN 5 THEN 'Decryption in progress'

 WHEN 6 THEN 'Protection change in progress'

 END) AS DatabaseEncryptionState

FROM sys.dm_database_encryption_keys 

WHERE database_id = DB_ID('AdventureWorks2019');

5. We can use the below command to validate whether the decryption process is completed or not

SELECT @@ServerName As ServerName, Name AS DatabaseName, is_encrypted IsEncrypted

FROM sys.databases WHERE name = 'AdventureWorks2019';

6. Secure DB Full backup after completion of the decryption process.

Conclusion:

Providing transparent encryption of database files while they are at rest, TDE is a useful feature in SQL Server 2019 that improves data security and shields private data from unauthorized access. Although it provides benefits for data privacy and compliance, it is important to take into account the possible performance effect and be aware of its limits. Organizations may use TDE to properly protect their data if they complete the essential implementation stages and provide the right permissions.

Q1: In SQL Server 2019, can TDE be enabled on system databases?

Ans: TDE may be configured to provide encryption for system-level data on databases such as master, model, and tempdb.

Q2: Does TDE shield data in memory or during transmission?

Ans: No, TDE simply encrypts the database files while they are in storage. To safeguard data in transit, additional security measures like SSL/TLS should be put in place.

Q3: Can certain database objects or columns be utilized with TDE?

Ans: No, TDE encrypts all database files at the database level and operates at that level. Other encryption techniques should be taken into account if a specific object or column-level encryption is needed.

Q4: In SQL Server Always On Availability Groups, can TDE be used?

Ans: TDE can offer encryption for replicated databases when used with Always On Availability Groups.

Q5: What happens if the TDE certificate is damaged or lost?

Ans: The database encryption key cannot be used to decrypt the database if the TDE certificate is missing or damaged, which results in data loss. To avoid such situations, it is essential to have effective backup and key management methods in place.

Q6: Can TDE be utilized with SQL Server 2019 in all editions?

Ans: No, TDE is offered in both the Enterprise and Standard Editions of SQL Server 2019. The Express Edition doesn't have it.

Q7: Can SQL Server 2019's Always Encrypted functionality be utilized in conjunction with TDE?

Ans: Yes, SQL Server 2019's TDE and Always Encrypted capabilities work well together. While Always Encrypted allows for the encryption of particular columns with encryption keys kept outside the database, TDE offers encryption at rest.

Q8: Does TDE have an impact on database backups and restorations?

Ans: The database backup files are encrypted when TDE is enabled. We must transmit master key information during a restoration process.