Microsoft Azure offers a plethora of tools and services for data engineering that enables secure and efficient handling of data, including writing encrypted data to tables or Parquet files. This mechanism ensures that confidential data is always secured from unauthorized access, even when stored or during transmission. The most popular Azure tools used for this purpose are Azure SQL Database Always Encrypted, Azure Data Lake Storage service, and Azure Blob Storage service.
I. Azure SQL Database Always Encrypted
Azure SQL Database Always Encrypted is a feature designed to protect sensitive data, such as credit card numbers or national identification numbers, stored in Azure SQL Database or Azure SQL Managed Instance. It allows clients to encrypt sensitive data inside client applications, never revealing the encryption keys to the database engine.
Here is an example of how to encrypt columns in an Azure SQL database using Always Encrypted:
sql
CREATE TABLE Customers
(
CustID int IDENTITY (1,1) PRIMARY KEY,
CustSSN char(11) ENCRYPTED WITH (ENCRYPTION_TYPE = RANDOMIZED, ALGORITHM = ‘AEAD_AES_256_CBC_HMAC_SHA_256’, COLUMN_ENCRYPTION_KEY = CEK1) NOT NULL,
CustName nvarchar(50) NOT NULL,
CustAddr nvarchar (50) NULL
)
II. Azure Data Lake Storage Service and Azure Blob Storage Service
Azure Data Lake Storage service offers the capability to store giant amounts of data with unlimited scalability potential. On the other hand, Azure Blob Storage is ideal for storing massive amounts of unstructured data, such as text or binary data.
- Data Lake & Blob Storage with Azure Key Vault for encryption:
Azure Key Vault is used to safeguard cryptographic keys and secrets used by the Azure services and applications. The keys for Data Lake & Blob Storage are stored in this Azure Key Vault. Whenever a file is written to these storage services, it is encrypted using these keys.
Here is a PowerShell script to write encrypted data to the blob.
PowerShell
# Get storage context
$ctx = New-AzureStorageContext -StorageAccountName “YourStorageAccountName” -StorageAccountKey “YourStorageAccountKey”
# Create blob
$blob = Set-AzureStorageBlobContent -File .\local-file-path.txt -Container “YourContainerName” -Blob “YourBlobName” -Context $ctx
# Upload blob with encryption
$blob.ICloudBlob.UploadFromFile(“.\local-file-path.txt”, System.IO.FileMode.Open, New-AzureKeyVaultKeyIdentifier(“https://YourKeyVaultName.vault.azure.net/keys/YourKeyName/YourKeyVersion”))
- Writing encrypted data to Parquet files:
Parquet is columnar store file format optimized for the needs of big data. Apache Parquet provides a data encryption mechanism referred to as envelope encryption whereby data is encrypted using a data encryption key (DEK), and this key is then encrypted using a key encryption key (KEK).
Azure Data Factory and Azure Databricks provide the means to write encrypted data to Parquet files in Azure Data Lake. Using Azure Databricks, data portion is encrypted using the DEK and then the DEK is encrypted using the KEK.
It’s important to remember that while writing encrypted data offers an extra layer of protection against unauthorized access, it should complement additional security measures such as vigilant access control, robust firewalls and intrusion detection/prevention systems.
Practice Test
True or False: Azure Data Lake Store supports the storage of Parquet files.
- 1) True
- 2) False
Answer: True
Explanation: Azure Data Lake Store supports storing Parquet files, which can be used for writing encrypted data.
Which of the following Azure services can be used to write encrypted data to tables?
- 1) Azure SQL Server
- 2) Azure Storage Account
- 3) Azure Cosmos DB
- 4) Azure Cache
Answer: Azure SQL Server, Azure Storage Account, Azure Cosmos DB
Explanation: All these services support writing encrypted data to tables. Azure is a part of Cloud Encryption that handles data encryption for these services.
True or False: Encrypted data can be stored in Parquet files using Azure Data Factory.
- 1) True
- 2) False
Answer: True
Explanation: Azure Data Factory supports copy activity that copies data from supported source data stores to sink data stores, including Parquet files.
What type of columns does Azure support for encryption at rest?
- 1) String
- 2) Binary
- 3) All types
Answer: All types
Explanation: Azure supports encryption at rest for all types of columns, regardless of the data type.
Does Azure automatically encrypt data written to Azure Storage Account?
- 1) Yes
- 2) No
Answer: Yes
Explanation: Azure automatically encrypts data before persisting it to Azure Storage Account and decrypts it before retrieval, providing encryption at rest automatically.
Can you directly write encrypted data to Azure Synapse Analytics?
- 1) Yes
- 2) No
Answer: No
Explanation: While Azure Synapse Analytics can handle encrypted data, it requires that data be transferred using a service like Azure Data Factory.
Which of the following service(s) can be used to write encrypted data to Parquet files?
- 1) Azure Data Lake Store
- 2) Azure Databricks
- 3) Azure Data Factory
- 4) All of the above
Answer: All of the above
Explanation: All these services support writing encrypted data to Parquet files, either directly or indirectly.
True or false: Azure Data Factory supports writing unencrypted data into encrypted tables in Azure Cosmos DB.
- 1) True
- 2) False
Answer: False
Explanation: Azure Data Factory supports writing encrypted data to various data storage platforms, including Azure Cosmos DB.
Can Azure Data Lake Store Gen2 write encrypted data to tables?
- 1) Yes
- 2) No
Answer: Yes
Explanation: Azure Data Lake Store Gen2 provides encryption at rest by default.
Is the encryption of data at rest in Azure SQL Server and Azure Storage Account automatic or manual?
- 1) Automatic
- 2) Manual
Answer: Automatic
Explanation: Encryption of data at rest in Azure SQL Server and Azure Storage Account is automatic and handled by Azure at the backend.
Which Azure service provides encryption keys for data written to Parquet files?
- 1) Azure Key Vault
- 2) Azure Active Directory
- 3) Azure Security Center
- 4) Azure Monitor
Answer: Azure Key Vault
Explanation: Azure Key Vault provides secure storage for encryption keys and allows services like Azure Databricks to encrypt and decrypt data when writing to or reading from Parquet files.
True or False: Azure Storage Service Encryption (SSE) can be used to write encrypted data to Parquet files.
- 1) True
- 2) False
Answer: True
Explanation: Azure Storage Service Encryption (SSE) is used to encrypt data at rest. Azure automatically encrypts data before storing and decrypts before retrieval. This applies to Parquet files as well.
Does Azure recommend using third-party encryption tools for data to be written in Azure Storage Account?
- 1) Yes
- 2) No
Answer: No
Explanation: Azure provides its encryption system, Azure Storage Service Encryption (SSE), and recommends using it for standardizing security.
True or False: Azure Data Factory does not support any transformation or cleaning of encrypted data before writing to tables or Parquet files.
- 1) True
- 2) False
Answer: False
Explanation: Azure Data Factory supports various data transformations, cleaning activities, and pipeline activities before writing data to the destination.
Are Parquet files used to write encrypted data a type of columnar storage?
- 1) Yes
- 2) No
Answer: Yes
Explanation: Parquet files are a type of columnar storage file that can handle encrypted data.
Interview Questions
What is Parquet file format?
Parquet is a columnar file format that is optimal for interactive and serverless data analytics. It provides efficient data compression and encoding schemes with enhanced performance.
How are encrypted data written to tables?
Encrypted data can be written to tables by first encrypting it using mechanisms such as T-SQL functions or Always Encrypted feature with Azure, then the encrypted data is written to the table in the encoded format.
Is Azure Data Lake Store suitable for storing Parquet files?
Yes, Azure Data Lake Store is suitable for storing Parquet files because it can optimize reading data for analytical processing with its columnar storage format.
What is the benefit of writing encrypted data to Parquet files?
Writing encrypted data to Parquet files enhances data security because encrypted data cannot be read without the corresponding decryption key.
Why would one choose to write data in Parquet file format.
Data in Parquet files are organized by column, allowing better compression and improved read times. This makes it excellent for storing and processing large amounts of data.
What role does Azure Key Vault play with encrypted data?
Azure Key Vault securely stores and tightly controls access to tokens, passwords, certificates, API keys, and other encryption keys. This enables a secure infrastructure that can help manage and automate keys and secrets used for encrypting/decrypting data.
What is the purpose of Azure Blob Storage in relation to Parquet files?
Azure Blob Storage can be used to store Parquet files due to its scalability and cost-effectiveness. It can securely hold large amounts of unstructured and semi-structured data, accommodating the scale and performance needs of big data analytics.
What should you use to encrypt data in Azure?
Azure provides a range of encryption services including Azure Disk Encryption for virtual machines, Storage Service Encryption for at-rest data, Azure Key Vault for keys and secrets, and Always Encrypted for SQL data.
Does Azure Data Factory support Parquet format?
Yes, Azure Data Factory supports Parquet format. It also supports column mapping for Parquet, which allows you to map data from your input data to Parquet columns directly.
Can Azure Data Lake Analytics process Parquet files?
Yes, Azure Data Lake Analytics has built-in support for processing the Parquet format. It has the ability to intelligently read from and write to Parquet files.
How does Always Encrypted function in Azure SQL Database?
Always Encrypted is a feature designed to protect sensitive data, such as credit card numbers or national identification numbers stored in Azure SQL Database. It allows clients to encrypt sensitive data inside client applications and never reveal the encryption keys to the Database Engine.
What is Transparent Data Encryption in Azure?
Transparent Data Encryption (TDE) is a security feature in Azure SQL Database that performs real-time encryption and decryption of the database, associated backups, and transaction log files at rest without requiring changes to the application.
How does Azure handle encryption keys with Parquet files?
In Azure, you can encrypt Parquet files at rest using Azure Storage Service Encryption. The encryption keys are stored and managed by Azure Key Vault.
Can Parquet format handle complex nested data structures?
Yes. Unlike CSV and TSV, Parquet retains the schema along with the data. Therefore, it supports complex nested data structures.
What are the benefits of columnar storage in Parquet file format?
Columnar storage like Parquet is beneficial for analytical queries where aggregates are computed over large amounts of data. It allows faster retrieval of data and offers better compression, saving storage and query time.
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