Object-level encryption is important when dealing with highly secure data. In Microsoft Azure SQL, this can be achieved using Transparent Data Encryption (TDE) or Always Encrypted (AE) techniques. TDE offers a broad level of encryption, while AE gives us the ability to encrypt at the column level. This article will focus on object-level encryption using Always Encrypted technology.
Always Encrypted
Always Encrypted is a feature designed to protect sensitive data, such as credit card numbers or national identification numbers (e.g., U.S. social security numbers), stored in Azure SQL Database or SQL Server databases. Always Encrypted allows clients to encrypt sensitive data inside client applications and never reveals the encryption keys to the Database Engine.
Implementing Always Encrypted
Always Encrypted involves two types of keys: Column encryption keys (CEKs) and column master keys (CMKs).
- CEK: It is used to encrypt data in the database columns.
- CMK: It is used to protect the CEKs. The Database Engine doesn’t have access to the CMK. Instead, the CMK is stored in a trusted key store, like Azure Key Vault.
Here’s a generalized way to setup Always Encrypted for your data in SQL Server Management Studio (SSMS):
- Connect to an instance of the SQL Server Database Engine or Azure SQL Database, expand the server, and then expand Databases.
- Expand the database where you want to secure your data, and then select ‘Tasks’.
- In the Tasks menu, Choose ‘Encrypt Columns’. The Always Encrypted Wizard will open up.
- Define the columns that you would like to encrypt, the encryption type (deterministic or random), and key settings.
The corresponding SQL code might look like:
Create Column Master Key MyCMK
With (
Key_Store = 'EKM-provider-name',
Key_Path = 'EKM-provider-specific-key-path'
);
Create Column Encryption Key MyCEK
With Values
(
Column_Master_Key = MyCMK,
Algorithm = 'RSA_OAEP',
Encrypted_Value = 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
);
Create Table dbo.Patients
(
[SSN] varchar(11) Collate Latin1_General_BIN2 Encrypted With (Column_Encryption_Key = MyCEK, Encryption_Type = Deterministic, Algorithm = 'AEAD_AES_256_CBC_HMAC_SHA_256',
[FirstName] varchar(50) Collate Latin1_General_BIN2 Encrypted With (Column_Encryption_Key = MyCEK, Encryption_Type = Randomized, Algorithm = 'AEAD_AES_256_CBC_HMAC_SHA_256',
[LastName] varchar(50) Collate Latin1_General_BIN2 Encrypted With (Column_Encryption_Key = MyCEK, Encryption_Type = Randomized, Algorithm = 'AEAD_AES_256_CBC_HMAC_SHA_256',
MiddleName varchar(50),
Age int
);
This example creates a column master key, a column encryption key, and a table with encrypted columns.
Implementing object-level encryption in Azure SQL Solutions is crucial to securing database information. Always Encrypted is one such technique that offers column-level encryption, ensuring sensitive data remains confidential and secure from unauthorized users. With Always Encrypted, your data remains encrypted at rest and in transit, providing a greater layer of security for data in your SQL databases.
Practice Test
True or False: Object-level encryption can only be implemented on Azure SQL Server.
- True
- False
Answer: False
Explanation: Object-level encryption can be implemented on Azure SQL Server as well as Azure SQL Database and Azure SQL Managed Instance.
Which are the types of encryption in Microsoft Azure?
- A. Transparent Data Encryption
- B. Object-level encryption
- C. Column-level encryption
- D. Row-level encryption
Answer: A, B, C
Explanation: Microsoft Azure supports Transparent Data Encryption (TDE), Object-level Encryption (OLE), and Column-level Encryption (CLE). Row-level Encryption is not supported in Azure.
True or False: Object-level encryption allows encryption of specific columns of a table at database level.
- True
- False
Answer: True
Explanation: Object Level Encryption supports encryption at a much granular level, i.e., at column level inside a table. It provides more flexibility and control than whole database encryption methods.
Which of the following Secure Enclave Azure platform do support?
- A. Azure SQL Database
- B. SQL Server on Azure VM
- C. Azure Cosmos DB
- D. Azure SQL Managed Instance
Answer: D. Azure SQL Managed Instance
Explanation: Currently, only Azure SQL Managed Instance support Secure Enclave, which is required for object-level encryption.
True or False: To implement object-level encryption, you must first enable Transparent Data Encryption (TDE) for the database.
- True
- False
Answer: False
Explanation: TDE encrypts the entire database. It is not necessary to first enable TDE to implement object-level encryption.
What role does Azure Key Vault play in object-level encryption?
- A. It stores encrypted data
- B. It manages database keys
- C. It processes transactions
- D. It controls network access
Answer: B. It manages database keys
Explanation: Azure Key Vault provides secure key management for encryption keys used with object-level encryption.
True or False: You cannot use object-level encryption and Always Encrypted with secure enclaves together in Azure SQL Database.
- True
- False
Answer: False
Explanation: You can use both object-level encryption and Always Encrypted with secure enclaves together in Azure SQL Database for enhanced data security.
True or False: Object-level encryption doesn’t support encryption of specific cells of a table.
- True
- False
Answer: True
Explanation: Object-level encryption supports column level encryption but not at the individual cell level.
During object-level encryption, if there is a client application, where does the encryption of sensitive data occur?
- A. On the client machine
- B. In Azure storage
- C. In the database
- D. In Azure Key Vault
Answer: A. On the client machine
Explanation: With object-level encryption, sensitive data is encrypted on the client machine before it is sent to the database.
Which keys are necessary for object level encryption in Azure SQL solutions?
- A. Column encryption key
- B. Master Key
- C. User Key
- D. All of the above
Answer: D. All of the Above
Explanation: To implement Object Level encryption, you need a column encryption key, a master key, and a user key. The column encryption key is used to encrypt/decrypt columns in the database. The master key is a key-encrypting key used to encrypt the column encryption key. The User Key is used to control access to the encrypted data.
Interview Questions
1. What is the main purpose of object-level encryption in Azure?
Object-level encryption primarily offers effective confidentiality and data protection by encrypting individual columns in a database at application level.
2. In what kinds of circumstances might object-level encryption be necessary?
Object-level encryption is necessary when sensitive data such as credit card numbers or social security numbers are being stored in the database, or when compliance with data protection standards, like GDPR, is required.
3. What is Transparent Data Encryption (TDE) in Azure SQL Database?
TDE is a security feature that provides real-time encryption and decryption of the database, its associated backups, and transaction log files at rest without requiring any changes to the application.
4. Is it possible to combine object-level encryption with other encryption methods in Azure SQL?
Yes, it can be combined with other encryption methods such as Transparent Data Encryption at the database level, for a layered approach to security.
5. How is the encryption and decryption of data handled in Object-Level Encryption?
In object-level encryption, encryption and decryption is performed within the application, before it writes data to or reads data from the database.
6. What are the two main types of keys used in object-level encryption and what are their roles?
The two main types of keys are the column encryption key (CEK) which encrypts the data of sensitive columns and the column master key (CMK) which protects the column encryption key.
7. What encryption algorithms does Azure SQL support for object-level encryption?
Azure SQL supports deterministic and random encryption algorithms for object-level encryption, which are also known as ‘Always Encrypted.’
8. What is the main drawback of implementing Object-level encryption?
The main drawback is that it can increase complexity within the application, since the application must handle encryption and decryption.
9. Can Object-Level Encryption protect data in transit and at rest?
While object-level encryption certainly protects data at rest, encryption during transit depends on the connection to Azure SQL Database being encrypted.
10. What is the difference between cell-level and object-level encryption?
The difference lies in their granularity. Cell level encryption allows you to encrypt individual cells in a database table, while object level encryption typically deals with larger structures such as entire data files or blobs.
11. Does Azure SQL Database support in-place encryption and decryption operations?
No, Azure SQL Database doesn’t support in-place encryption and decryption operations, so you’ll have to handle the operations within your application.
12. Can we rotate the Column Master Key in Object-Level Encryption?
Yes, Column Master Key rotation is supported, which is a security best practice to periodically change encryption keys.
13. Which tool can be used to implement object-level encryption in Azure SQL Database?
SQL Server Management Studio (SSMS) can be used to implement object-level encryption.
14. Can you perform sorting or searching operations on encrypted columns?
It largely depends on the encryption type used. Deterministic encryption allows for equality searches, grouping, indexing, and join operations. However, random encryption does not support these operations.
15. Can you enable always encrypted feature after the database creation?
Yes, the ‘Always Encrypted’ feature, which is used for object-level encryption, can be enabled after the database creation. But, you need to ensure your data is encrypted and any further database operations should accommodate the encrypted data.
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