Saturday, June 3, 2023

Always Encrypted in SQL Server

Outline of the Article:

1. Introduction

2. What does SQL Server's Always Encrypted functionality entail?

3. Benefits of Using Always-Encrypted

4. Problems with Always Encrypted

5. Advantages of Always Encrypted

6. Always Encrypted use

7. Detailed instructions for setting Always Encrypted

8. Examples of Always Encrypted implementation

9. Detailed responses to frequently asked questions regarding Always Encrypted

10. Conclusion

11. FAQs

SQL Server's Always Encrypted functionality


We shall examine SQL Server's Always Encrypted functionality in this tutorial. We shall go through its objective, benefits, drawbacks, and usage. Additionally, we will offer a step-by-step configuration manual for Always Encrypted, give examples of how it is used, and respond to frequently asked questions about this feature. We will have a thorough grasp of Always Encrypted and how it can improve the security of our network by the time we finish reading this article.

What does SQL Server Always Encrypt mean?

A security feature added to SQL Server in versions 2016 and beyond is called Always Encrypted. Since you can encrypt sensitive data at the column level, we can make sure that it stays protected throughout the database's full lifespan, even when it's being stored and transferred. Never being exposed in plaintext to the database engine or any other unauthorized parties is guaranteed by Always Encrypted, in contrast to conventional encryption techniques.

The Benefits of Always Encrypted:

For protecting sensitive data in SQL Server, Always Encrypted has a number of benefits, including:

Data Security: With Always Encrypted, confidential information is secure even when viewed by authorized database administrators or other privileged users. By doing this, threats from insiders are further protected.

Secure Data Storage: Encrypted information is safely kept in the database, reducing the possibility of data breaches or unauthorized access in the event of physical theft or unapproved access to the database files.

Transparent Encryption: Always Encrypted offers an encryption and decryption process that is transparent, allowing programs to access encrypted data without having to make any modifications to the application code.

Granular Encryption: This feature allows you to finely regulate which data is secured by encrypting only the individual columns that contain sensitive data.

Powerful Encryption: To guarantee the security of the encrypted data, Always Encrypted employs powerful encryption methods like the Advanced Encryption Standard (AES).

The drawback of Always Encrypted:

Even though Always Encrypted offers considerable security advantages, there are several restrictions and possible downsides:

Limited Query Capabilities: Some activities, such as sorting, searching, and indexing, may be constrained or need more processing costs due to the encryption of data.

Greater Storage Needs: Compared to unencrypted data, encrypted data takes up more storage space. Planning database capacity should take this rise in storage needs into account.

Key management: Handling a number of databases or environments at once might make managing encryption keys difficult. For the purpose of preventing data loss and unauthorized access to the keys, proper key management procedures must be followed.

Using Always Encrypted Has Many Advantages

The following advantages may be had by adopting Always Encrypted in your SQL Server environment:

Through constant encryption of important data, Enhanced Data Security: Always Encrypted greatly lowers the danger of data breaches.

Data protection regulations compliance: By encrypting sensitive data, you may adhere to the data protection standards imposed by laws like the General Data Protection Regulation (GDPR).

Keeping Data Private: Always Encrypted helps businesses to keep sensitive data private, even when third parties or cloud service providers are in charge of the database infrastructure.

Secure Data Sharing: Data that has been encrypted may be safely shared with other databases or apps, enabling secure cooperation without jeopardizing the privacy of the data.

Usage of Always Encrypted:

Always Encrypted can be utilized in a variety of situations when safeguarding sensitive data is essential, including:

Protecting Personally Identifiable Information (PII): Businesses that deal with PII, such as credit card numbers or social security numbers, can utilize Always Encrypted to guarantee the confidentiality and security of this information.

Securing Healthcare Information: To abide by healthcare standards like the Health Insurance Portability and Accountability Act (HIPAA), medical records and patient information can be encrypted using Always Encrypted.

Financial Data Protection: To protect sensitive financial data, such as account numbers and transaction information, banks, and other financial organizations can use Always Encrypted.

An instruction manual for setting up Always Encrypted

Follow these steps to set up Always Encrypted in SQL Server:

Decide which columns should be encrypted: Determine which database columns contain sensitive information and should be encrypted.

Select the Encryption Method: Select the encryption technique and keys that will be used to secure the columns.

Generate Column Master Key: Create a Column Master Key to be used as a security measure for the Column Encryption Key(s).

Create the column encryption key: Produce the column encryption key(s) necessary for each encrypted column.

Modify the table and encrypt the columns: Specify the encryption settings for the chosen columns in the table structure.

Encrypt Data: Using the Column Encryption Key(s), encrypt any existing data that is present in the chosen columns.

Application updates: To utilize Always Encrypted and assure compatibility with the encrypted columns, update the application's code.

Examples of Always Encrypted implementation

Let's take the example of encrypting the "SSNumber" column in a "mCustomers" database. We can do the following:

Create the Column Encryption Key and Column Master Key.

The "SSNumber" column's encryption attributes should be defined in the "Customers" database.

Use the Column Encryption Key to encrypt the current data in the "SSNumber" column.

Change the application code such that Always Encrypted is used to securely access the "SSNumber" column.

Detailed responses to frequently asked questions regarding Always Encrypted


An efficient method for safeguarding sensitive data is offered by SQL Server's Always Encrypted functionality. Always Encrypted makes sure that your data stays private even in cases of unauthorized access or data breaches by encrypting data at the column level. It also provides several advantages, such as improved security, adherence to data protection laws, and safe data exchange. However, it's crucial to take into account the constraints and difficulties related to Always Encrypted, such as key management and query restrictions.

When implementing Always Encrypted, careful planning and configuration are needed. The necessary columns must be encrypted one step at a time. Your SQL Server installation may develop a strong security architecture and safeguard your critical data from unauthorized access by using Always Encrypted.


Q1: Does SQL Server Always Encrypted come with all editions?
Ans: Yes, starting with SQL Server 2016, Always Encrypted is available in all versions of the database server.

Q2: Can SQL Server running on Azure be utilized with Always Encrypted?
Ans: Yes, SQL Server running on Azure fully supports Always Encrypted, allowing for safe cloud data storage.

Q3: Does utilizing Always Encrypted have any effects on performance?
Ans: Data encryption and decryption can incur extra processing overhead, which may have an impact on query performance. It's crucial to benchmark and gauges the effects on your particular workload.

Q4: Can I modify Always Encrypted's encryption algorithm or key?
Ans: To maintain the availability and integrity of the encrypted data, meticulous preparation and collaboration are required when changing the encryption method or key. It is advised to adhere to best practices and seek advice from Microsoft's guidelines.

Q5: Can I combine columns that are encrypted and those that aren't in the same table?
Ans: Yes, a table may have both encrypted and unencrypted columns. Depending on your needs, Always Encrypted enables you to selectively encrypt particular columns.

Q7: When privileged database administrators view data, can Always Encrypt still safeguard that information?
Ans: Yes, Always Encrypted makes sure that nobody can access sensitive data in plaintext, not even privileged administrators. They are limited to interacting with encrypted data.

Q8: Can I do computations on columns that are encrypted?

Ans: No, computations cannot directly use encrypted columns. However, after decrypting the data in the client program, you can manipulate it.

Q9: Is it possible to utilize Always Encrypted in conjunction with other security measures?

Ans: Transparent Data Encryption (TDE) and row-level security, among others, can be utilized in conjunction with Always Encrypted.

Q10: Can I index columns that are encrypted?

Ans: Indexing is possible, but only with deterministic encryption techniques. Indexing is incompatible with randomized encryption techniques.

Q11: Data in backups can be protected via Always Encrypted.

Ans: By encrypting the delicate columns, Always Encrypted safeguards data in backups. However, in order to restore and view the encrypted backups, adequate key management is required.

Q12: Is it possible to switch an existing database to Always Encrypted?

Ans: You can move an existing database to Always Encrypted, yes. However, to guarantee a seamless transition, rigorous preparation and testing are required.

Q13: How do data encryption keys get handled by Always Encrypted?

Ans: Column Encryption Keys (CEK) and Column Master Keys (CMK) are the two different kinds of keys that Always Encrypted utilises. The data in the column is encrypted by the CEK, and the CEK is safeguarded by the CMK.

Q14: Can I do range queries on columns that are encrypted?

Ans: Randomised encryption systems do not enable range queries on encrypted columns. Deterministic encryption schemes do.

Q15: Can I use Always Encrypted with AlwaysOn Availability Groups or SQL Server Replication?

Ans: Yes, Always Encrypted is compatible with AlwaysOn Availability Groups and SQL Server Replication. However, extra factors for setup and key management can be necessary.

Q16. When data is being sent between a client application and a database, is Always Encrypted protecting it?
Ans: Data in transit is not expressly protected by Always Encrypted. It concentrates on encrypting database data while it is at rest. You should utilize technologies like SSL/TLS encryption to protect data while it is being sent.

Q17: Aside from SQL Server, what other database platforms can I utilize Always Encrypted with?
Ans: Always Encrypted is a SQL Server capability that isn't directly accessible on other database systems. Other database systems could, however, provide comparable encryption features.

Q18: Can I combine and compare columns that are encrypted?
Ans: Yes, given the encryption method chosen is predictable, Always Encrypted enables joins and compares on encrypted columns.

Q19: Can I use Entity Framework or other ORMs with Always Encrypted?
Ans: Entity Framework and other Object-Relational Mapping (ORM) frameworks do offer Always Encrypted. Specific solutions for handling encrypted columns are available from ORM suppliers.

Q20: What happens if I misplace the Always Encrypted encryption keys?
Ans: If Always Encrypted's encryption keys are lost, the encrypted data may never be recovered or may no longer be able to be decrypted. It is essential to adhere to correct key management procedures and guarantee safe key backup and storage.

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