Always Encrypted feature in SQL Server


Always Encrypted is used for encryption at the column level rather than the entire database. It provides both data at rest as well in memory (in flight).

It is different from column (cell-level) and Transparent Data Encryption (TDE) which uses keys and certificates, which are stored in the database. In the case of Always Encrypted, keys are managed outside the database. SQL Server cannot decrypt on its own, as it is the client who encrypts / decrypts on the fly, separating those who own the data from the one who manages it.

To enable Always Encrypted we can use either T-SQL or the Always Encryption Wizard in SSMS. It supports both Randomized and Deterministic Encryption types.

  • Columns are encrypted using CEK – Column Encryption Key.
  • The encrypted versions of each CEK are stored in the database.
  • CMK – Column Master Key is used to encrypt all the CEKs.
  • Only the client possesses the CMK which is stored in either Azure Key Vault, Certificate Store, HSM.

SSMS Wizard generates both CEK and CMK. CMK is stored in the Client certificate or Azure Key Vault.

CMK is used to encrypt CEK. The encrypted CEK along with Path to CMK is what is stored in the database. So, the database has no way of decrypting the data.

Next SSMS Wizard begins the encryption process, where it creates a new temporary table, transfers the data from the table and encrypts it on the fly, and then drops and replaces the main table.

All of this occurs on the fly at the client side which is SSMS in this case.

The client will pass the ‘Column Encryption Setting=Enabled’ in the connection string, which fetches the Encrypted CEK and Path to CMK from the database.

The client uses the Path to CMK to get the CMK and uses it to decrypt the encrypted CEK received and then uses the CEK to decrypt the encrypted data.

To apply Always Encrypted, within SSMS, right-click the database and select Tasks > Encrypt Columns…

Below we have selected the Email Id column of MyContact table.

The below wizard step is used for generating CMK which can be either stored in Windows Certificate Store or Azure Key Vault with the client.

We can either run the encryption at that time or choose to generate a PowerShell Script which we can run later.

Below is the summary of steps that will be performed

  • Before encryption

  • After encryption

To decrypt here, at the client which is our SSMS in this case, right-click in the query window and select Connection > Choose Connection…


Specify column encryption setting=enabled in the Additional Connection Parameters tab.

We can see the actual data as the client SSMS in this case, peforms the decryption at the run time using the path to CMK and encrypted CEK details received from the database.

  • Usage within a console application –

Few points to consider while planning to use Always Encrypted –

https://www.sentryone.com/blog/aaronbertrand/t-sql-tuesday-69-always-encrypted-limitations

Reference – Pluralsight – SQL Server Course 

Hope it helps..

Author: Nishant Rana

I love working in and sharing everything about Microsoft.NET technology !

2 thoughts on “Always Encrypted feature in SQL Server”

  1. Thank you for the informative piece. Do you know if this encrypted feature would work to encrypt a specific field in Microsoft CRM?

    Like

Leave a Reply to Elisabeth Cancel reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

This site uses Akismet to reduce spam. Learn how your comment data is processed.

Welcome to the Blog & Website of Paul Andrew

Technical Leadership Centred Around the Microsoft Data Platform

Deriving Dynamics 365

Deriving Solutions and features on Power Platform/Dynamics 365

The CRM Ninja

Thoughts & musings from a Dynamics 365 Ninja!

CRM for You and Me

Customer Relationship Mgt App for the Professional

D CRM Explorer

Learn about Microsoft Dynamics CRM Power Platform customization and implementation and other cool stuffs

Stroke // Jonas Rapp

I know pre-stroke. I will improve who I was.

Power Melange

Power Melange By Shalinee

Clavin's Blog

Power Automate - Power Apps - SharePoint Online - Azure - Nintex - K2 - Artificial Intelligence

Sat Sangha Salon

An Inquiry in Being

The Indoencers

The Influencers & Influences of Indian Music

Monika Halan's blog

Hand's-free money management

D365 Demystified

A closer look at Microsoft Dynamics 365.

Microsoft Mate (msftmate) - Andrew Rogers

Experienced consultant primarily focused on Microsoft Dynamics 365 and the Power Platform

Knowhere365

Specific topics by Django Lohn on the whole Microsoft365 Stack

Manmit Rahevar's Blog

One Stop Destination for Microsoft Technology Solutions

MG

Naturally Curious

Brian Illand

Power Platform and Dynamics 365

Steve Mordue MVP

A Microsoft Business Applications MVP

Subwoofer 101

Bass defines your home theater

SQLTwins by Nakul Vachhrajani

SQL Server tips and experiences dedicated to my twin daughters.

Everything D365

Discovering Azure DevOps and D365 Business Applications

Tech Wizard

Lets do IT Spells

XRM Tricks (Power Platform & Dynamics CRM )

Power Platform & Dynamics CRM

CRM TIPS BY PRM

Mail to crmtipsbyprm@gmail.com for queries and suggestions

nijos.dev

Giving back to the community what I have learned

xrm CRM Dynamics

Dynamics CRM Technical & Functional Info

Dynamics 365 Blogs - Explained in unique way

Sometimes you need to look at things from different perspective.

CRM Keeper

Dynamics 365 Customer Engagement, CRM, Microsoft CRM, Dynamics CRM

EVOLVED365

Step into the world of a Dynamics 365 Consultant

Dianamics PCF Lady

Diana & Dynamics 365 & Power Platform

Sara Lagerquist

No Code Customization Concepts

innovativeaj

developer, designer, writer, fun loving, patriotic, humble and a sweet person inside out :) love and respect people who have a great sense of humor.

Temmy Wahyu Raharjo

dreaming to be a clean coder and TDD minded programmer.

%d bloggers like this: