How to Encrypt a Database Column in SQL?

Encrypting a Database Column

Write a SQL query to encrypt a sensitive column using Transparent Data Encryption (TDE).

Solution:

-- Enable encryption on the SSN column.
ALTER TABLE Employees
ALTER COLUMN SSN VARBINARY(MAX) ENCRYPTED WITH (
    ALGORITHM = AEAD_AES_256_CBC_HMAC_SHA_256,
    COLUMN_ENCRYPTION_KEY = CEK_Auto1
);

Explanation:

• Purpose of the Query :
• The goal is to demonstrate how to encrypt sensitive data to protect it from unauthorized access.
• Key Components :
• ALTER COLUMN: Modifies the column to enable encryption.
• ENCRYPTED WITH: Specifies the encryption algorithm and key.
• AEAD_AES_256_CBC_HMAC_SHA_256: A strong encryption algorithm.
• Why Use Encryption? :
• Encryption protects sensitive data at rest and in transit.
• It ensures compliance with data protection regulations.
• Real-World Application :
• In banking systems, encryption secures customer account numbers.

Additional Notes:

• Transparent Data Encryption (TDE) is supported in SQL Server and Azure SQL Database.
• Manage encryption keys securely to prevent data loss.
• Important Considerations:
• Test encryption performance to ensure minimal impact.

For more Practice: Solve these Related Problems:

• Write a SQL query to encrypt the Password column in the Users table using AES encryption.
• Write a SQL query to enable Transparent Data Encryption (TDE) on the entire database.
• Write a SQL query to encrypt the CreditCardNumber column in the Payments table and manage the encryption keys securely.
• Write a SQL query to decrypt and retrieve data from an encrypted column for authorized users only.

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