Data protection is very crucial in today’s modern tech era. Especially for any organization that stores the personal details of their customers in their database. The main goal of SQL Data Encryption is to protect unauthorized access to data within or outside the organization. In this article, we will be going through the basics of SQL data encryption, its types, and methods to implement Data Encryption in SQL databases.

What is SQL Data Encryption and How it Works?

SQL data encryption involves converting the sensitive data of the database into an unreadable format using various kinds of cryptographic algorithms. Only responsible persons will be able to access the actual data through the decryption key. The SQL database supports various encryption methods, each with its unique characteristics and applications. Before deep diving into the types of SQL data encryptions let us understand how encryption works.

Workflow of Encryption

Types of SQL Data Encryption

Transparent Data Encryption(TDE)

• TDE encrypts the entire database, including the actual data and the log files at rest. This process works seamlessly in the background without affecting the performance of the user program.
• TDE provides a transparent layer of security over the datbase with small changes in the actual database schema.
• TDE operates on the file level which encrypts the databse files on the disk.
• The encryption works automtically as it is read from or written in the databse.
• TDE uses symmetric key for securing the database.

How to implement TDE?

We can implement the Transparent Data Encryption using the 4 simple steps.

1. Create a database master key.
2. Create a certificate.
3. Create an encryption key.
4. Configure the database to use the encryption.

In order to implement the encryption we are creating the following demo table for better understanding.

CREATE TABLE Student
            (StudentID  INT PRIMARY KEY, 
             StudentName  VARCHAR(30) NOT NULL, 
             Rollumber VARCHAR(10) NOT NULL
            );

INSERT INTO Student  VALUES
(1, 'Ram', 1234),
(2, 'Shyam', 4321),
(3, 'Hari', 4554),
(4, 'Om', 7896);

Output

Database before Encryption

1. Create database Master key using the below command you can choose password of your choice.

USE dba;
Go
Create MASTER KEY ENCRYPTION BY PASSWORD = "ABC@123"
Go

2. Create Certificate using the below command

USE dba;
Go
CREATE CERTIFICATE TDE_Certificate
      WITH SUBJECT = 'Certificate for TDE'
Go

3. Create the Encryption Key using the below command.

USE dba
GO
CREATE DATABASE ENCRYPTION KEY
WITH ALGORITHM = AES_256
ENCRYPTION BY SERVER CERTIFICATE TDE_Certificate

4. Configure the database to enable encryption using the below command

ALTER DATABASE dba
SET ENCRYPTION ON

After Encryption we can see the data is encrypted completely.

After Encryption

Column-Level Encryption

• This method of encryption involves encrypting specific columns within a table rather than the whole table or the databse.
• This method allows organizations to selectively secure their data.
• Column level encryption is useful while dealing with databases that stores a combination of both sensitive and unsensitive data.
• CLE also operates on the file level which encrypts the database files on the disk.
• CLE uses also use the asymmetric key for data encryption.

How to implement CLE?

We can implement the Column level encryption using the 5 simple steps.

1. Create a database master key.
2. Create a self signed certificate for the SQL sever.
3. Configure a symmetric key for encryption.
4. Encrypt the column data.
5. Query and verify the data encryption.

In order to implement the encryption we are creating the same table we used for TDE for better understanding.

CREATE TABLE Student
            (StudentID  INT PRIMARY KEY, 
             StudentName VARCHAR(30) NOT NULL, 
             Rollumber VARCHAR(10) NOT NULL
            );

INSERT INTO Student  VALUES
(10, 'Rajendra', 1234),
(20, 'Manoj, 4321),
(30, 'Shyam, 4554),
(40, 'Akshita', 7896);

Output

Database before encryption

1. Create the database master key using the following command.

USE Student;
GO
CREATE MASTER KEY ENCRYPTION BY PASSWORD = '123@4321';

2. Create the self signed certificate using the following command

USE Student;
GO
CREATE CERTIFICATE Certificate_test WITH SUBJECT = 'Protect my data';
GO

3. Configure a symmetric key for column level encryption using the following command.

CREATE SYMMETRIC KEY SymKey_test WITH ALGORITHM = AES_256 ENCRYPTION BY CERTIFICATE Certificate_test;

4. Select the column in which you want to encrypt the data using the following command.

ALTER TABLE Student
ADD RollNumber_encrypt varbinary(MAX)

After Encryption we can see that now the data is unidentifiable.

After encryption

Benefits of SQL Data Encryption

Following are the benefits of the SQL data encryption:

• 1. Data Protection from Unauthorized Access.
• 2. Enhanced Data Security which reduces the risk of data breaches and unauthorized disclosure of sensitive data.
• 3. Data Inegrity which ensures that the sensitive of users is not tampered or modified.
• 4. Selective Encryption ensures that the user can selectively encrypt the data as per their needs.
• 5. Minimized Impact on performance ensures that the encryption of the data doesn’t slows down the overall performance of the system.

Conclusion

The data encryption is very crucial if you are an organization and you are storing the data of your customers. The choice on the type of encryption completely depends on your personal choice whether you want to encrypt the whole data or selective data. If you want to encrypt the whole data then go with TDE and if you want to encrypt the selective data then go with CLE. Ultimately we hope that this article helped you to understand about the SQl data encryption.

FAQs on SQL Data Encryption

Q.1: Is SQL data encryption necessary?

Answer:

The choice of data encryption is not mandatory. It completely depends on your personal choice and needs.

Q.2: What is the role of certificate in SQL data encryption?

Answer:

A certificate binds a public key to an identity, which ensures that the public key belongs to the trusted entity.

Q.3: What is the difference between symmetric and asymmetric encryption?

Answer:

Symmetric encryption uses a single key for both the encryption and decryption where as asymmetric encryption uses a pair of keys where a public key is used for encryption and private key is used for decryption.

Q.4: Which encryption method should we use TDE or CLE?

Answer:

If you want to encrypt the whole database the use TDE and if you want to selectively encrypt the data then use the CLE method .