How to encrypt MS SQL Database


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In this digital period, encrypting your data is significantly important because you do not want any unauthorized person or authority to access the sensitive data. Whether you have your data on your local disk or save it over the network or whether you enter your password, encrypting the data is necessary.

MS SQL Server Data Encryption

MS SQL Server follows a hierarchical encryption management with the key management i.e., each ongoing layer covers the preceding layer using keys and certificates. Both symmetric and asymmetric keys can be saved in an Extensible Key Management (EKM) module outside the SQL Server. The symmetric keys are considered to give best performances in encrypting data. Key managements are cost effective that is not difficult to achieve and has no impact on the performance of an application.

How to Encrypt data in MS SQL Server?

MS SQL Server comes with multiple ways to encrypt the data such as TED and keys. If you have an older version of an SQL, encryption can be handled by using various alternate methods like Views and triggers which can automate the encryption process of data without doing massive changes to an application.

  • Transact-SQL Functions

In Transact SQL functions, individual items are encrypted at the time of insertion or updating. The data is encrypted using the TRIPLE DES algorithm passphrase.


EncryptByPassPhrase ( { ‘passphrase’ | @passphrase }, { ‘cleartext’ | @cleartext }   [ , { add_authenticator | @add_authenticator }  , { authenticator | @authenticator } ] )


  • Asymmetric Keys

An asymmetric key has private and a corresponding public key. In this key, any key can decrypt the data that is encrypted by the other key. They are known as resource intensive as they are more secure than symmetric keys. It can be used to encrypt a symmetric key also in a database.

  • Symmetric Keys

A symmetric key is used to encrypt and decrypt database. It is considered as fast and suitable for sensitive data in a database.

  • Certificates

Certificates provides an ability to do encryption across multiple communication channels. It allows encrypted open connections for an instance of MS SQL Server Data Engine. A server must have a valid certificated imported into an operating system. It is an electronic statement signed digitally, which connects the value of a key to the other entity. Certificates are signed and issued by a Certification Authority (CA).

  • Transparent Data Encryption

Transparent Data Encryption (TDE) is used to encrypt MS SQL Server database. It can also be used in the encryption of Azure SQL Database and Azure analytics datafiles. The Transparent Data Encryption is also called as encryption at rest. It encrypts and decrypts the data and log files at real time and does the protection of data. It uses a symmetric key known as Database Encryption Key (DEK), which is stored in the database recovery boot mode to make it available. It is secured with a certificate that is stored in a master database. Once the SQL Server is secured using the Transparent Data Encryption, it can be restored by using the correct certificate. It is recommended that whenever the SQL server is encrypted, the backup must be taken of the certificate and the associated data encrypted key.

MS SQL Server Database Security Threats

MS SQL Server is a relational database management software provided by Microsoft. It allows a software applications or web applications to store and retrieve data as needed by them. With this powerful feature, it also comes with the risk of data theft. A data risk can be in any given form like malwares, software vulnerabilities, SQL injection attacks, etc. It is not possible to run a business where a storage is not needed and there is no risk of data breaching. Typically, MS SQL Server database can have sensitive data but not restricted to user personal data, credit cards information, bank account numbers and balances, confidential medical information, etc.

Human Error

Human Error refers to those unplanned risks which are not caused intentionally but can have a serious impact on the database. The main possible threat is the disclosure of password. It is always recommended not to share passwords with any unauthorized user and maintain the privacy of data. Secondly, weak password is also the main reason behind data breaching.

SQL Injection

Typically, SQL Injection attacks are generated by the web applications or during a HTTP request for the purpose of stealing, deleting, changing the data. It can also be used to gain administrative rights in a database. SQL Injection involves a unique technique that might even destroy a database. The attacker puts the malicious code into any field which requires an input from the user like login credential field, search field, save field, etc.

DOS – Denial of Service Attacks

Denial of Service Attacks refers to the attacks which are caused by using the large number of requests and the database server cannot distinguish between the genuine and fakes requests.


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