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As a cornerstone of many business operations, databases are a treasure trove of information; they need to be effectively secured to protect sensitive information. Microsoft SQL Server introduced the Always Encrypted feature in SQL Server 2016, providing an additional layer of protection. Here, we look in detail at this feature, exploring how you can integrate it into your data protection strategy.
What is SQL Server Always Encrypted?
SQL Server Always Encrypted is a feature designed to protect sensitive data, such as Social Security numbers, credit card information or confidential business data. The core idea of Always Encrypted is that sensitive data stored in database columns remain encrypted and not disclosed to the SQL Server. Thus it assures that your data is safe even if your database is compromised.
Setting up Always Encrypted
To set up Always Encrypted, you’ll have to encrypt certain columns in a database table. Let me show you an example. Suppose we have a standard Customers table, and we want to ensure that data in the “Email” and “Phone” columns remains confidential.
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CREATE TABLE Customers ( CustomerId INT IDENTITY (1,1), FirstName NVARCHAR(50), LastName NVARCHAR(50), Email NVARCHAR(50) COLLATE Latin1_General_BIN2 ENCRYPTED WITH (ENCRYPTION_TYPE = DETERMINISTIC, ALGORITHM = 'AEAD_AES_256_CBC_HMAC_SHA_256', COLUMN_ENCRYPTION_KEY = CEK_Auto1), Phone NVARCHAR(50) COLLATE Latin1_General_BIN2 ENCRYPTED WITH (ENCRYPTION_TYPE = RANDOMIZED, ALGORITHM = 'AEAD_AES_256_CBC_HMAC_SHA_256', COLUMN_ENCRYPTION_KEY = CEK_Auto1) PRIMARY KEY CLUSTERED (CustomerId ASC) ); |
In this example, the ‘Email’ column uses deterministic encryption that allows grouping, indexing, and joining on the encrypted column. The ‘Phone’ column, on the other hand, uses randomized encryption, which provides a higher level of security because the same plaintext value results in a different ciphertext value every time it is encrypted.
Using Always Encrypted with client applications
Always Encrypted is designed to work transparently with client applications. ADO.NET, JDBC, and ODBC all support Always Encrypted. Here’s a simple example of a parameterized query that inserts encrypted data into the ‘Customers’ table using ADO.NET:
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using (SqlConnection connection = new SqlConnection(connectionString)) using (SqlCommand cmd = new SqlCommand("INSERT INTO Customers (FirstName, LastName, Email, Phone) VALUES (@FirstName, @LastName, @Email, @Phone)", connection)) { connection.Open(); cmd.Parameters.AddWithValue("@FirstName", "John"); cmd.Parameters.AddWithValue("@LastName", "Doe"); cmd.Parameters.AddWithValue("@Email", "<a href="mailto:john.doe@example.com" >john.doe@example.com</a>"); cmd.Parameters.AddWithValue("@Phone", "123-456-7890"); cmd.ExecuteNonQuery(); } |
Here, ‘@Email’ and ‘@Phone’ parameters are transparently encrypted before being sent to the database. On the database side, they’re stored as encrypted, and the SQL Server cannot decrypt them. The only place where they can be decrypted is inside the client application that has access to the encryption key.
Wrapping Up
Ensuring data security has become a priority in today’s data-driven world. SQL Server Always Encrypted offers a strong defense against potential security threats by keeping your sensitive data secure. However, like any good security strategy, its effectiveness heavily relies on regular maintenance, monitoring, and updating as required. Stay vigilant, stay encrypted.