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SQL Data Encryption

Last Updated : 27 Nov, 2024
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In today’s digital era, data security is more critical than ever, especially for organizations storing the personal details of their customers in their database. SQL Data Encryption aims to safeguard unauthorized access to data, ensuring that even if a breach occurs, the information remains unreadable without decryption keys. The main goal of SQL Data Encryption is to protect unauthorized access to data within or outside the organization.

In this article, we will provide an in-depth explanation of SQL data encryption, its types, and how to implement it with practical examples and outputs. By mastering SQL encryption techniques, We can significantly enhance our database security and acceptance of data protection regulations.

What is SQL Data Encryption and How it Works?

SQL data encryption is the process of converting sensitive database information into an unreadable format using cryptographic algorithms. Only authorized persons with the decryption key will be able to access the actual data. This ensures the security of data at rest and during transmission.

The SQL database supports various encryption methods, each with its unique characteristics and applications. Modern SQL databases support various encryption techniques, each catering to specific use cases and different levels of protection.

SQL_Encryption
Workflow of Encryption

Types of SQL Data Encryption

This section explores the various methods of securing data in SQL databases, including Transparent Data Encryption (TDE) and Column-Level Encryption (CLE). Each type is explained with its use cases, implementation steps, and benefits.

1. 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 database.
    database
  • TDE uses symmetric key for securing the database.

Steps to Implement TDE

Let’s implement TDE using the following steps. First, we will set up a demo table for better understanding:

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

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

Output

Output
Database before Encryption

Step-by-Step Implementation

1. Create a Database Master Key

The master key secures the encryption hierarchy. Use the following command and choose the password of your choice

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

2. Create a Certificate

A certificate is used to protect the encryption keys.

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

3. Create an Encryption Key

Define the database encryption key using a specific algorithm:

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

4. Enable Encryption

Configure the database to enable encryption using the below command

ALTER DATABASE dba
SET ENCRYPTION ON

Output

After Encryptions
After Encryption

2. Column-Level Encryption

This method of encryption involves encrypting specific columns within a table rather than the whole table or the database. 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.

Steps to Implement CLE

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

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

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

Output

Output
Database before encryption

Step-by-Step Implementation.

1. Create a Database Master Key

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

2. Create a Self-Signed Certificate

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

3. Configure a Symmetric Key

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

4. Encrypt Specific Columns

ALTER TABLE Student
ADD RollNumber_encrypt varbinary(MAX)

Output

After Encryption
After encryption

The RollNumber_Encrypted column will now contain encrypted values, rendering them unreadable to unauthorized users.

Benefits of SQL Data Encryption

  • Data Protection: Ensures sensitive data remains secure from unauthorized access.
  • Enhanced Security: Reduces the risk of data breaches and leaks.
  • Data Integrity: Maintains the accuracy and consistency of sensitive data.
  • Selective Encryption: Allows encrypting only critical data, optimizing performance.
  • Compliance: Meets regulatory requirements for data protection, such as GDPR or HIPAA.

Conclusion

SQL data encryption is a critical component of database security, offering both Transparent Data Encryption (TDE) for entire databases and Column-Level Encryption (CLE) for specific fields. Choosing the right encryption method depends on our organization’s requirements. whether we need comprehensive security or targeted protection for sensitive data.

By implementing these techniques, we can ensure that our data is secure, compliant, and accessible only to authorized individuals. Start encrypting our SQL databases today to safeguard our organization's most valuable asset that is the data.


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