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Data security is at the forefront of any organization’s priority list. With rampant cyber threats and data mismanagement practices, safeguarding sensitive information is essential. SQL Server Always Encrypted is a feature providing an exceptional level of data protection. A unique aspect of Always Encrypted is that it allows encryption and decryption inside the client application with no plaintext data or encryption keys revealed to the SQL Server.
How does SQL Server Always Encrypted Work?
SQL Server Always Encrypted ensures data protection in two ways. Firstly, it secures data at rest by encrypting sensitive data before sending it to SQL Server for storage. Secondly, it safeguards data in transit by making sure that data remains encrypted during querying and data retrieval processes.
Enabling Always Encrypted on SQL Server
To use Always Encrypted, you need to enable it on the database column holding sensitive data. Suppose we have a Customer table with a CreditCardNumber column we want to encrypt.
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ALTER TABLE dbo.Customers ADD COLUMN_ENCRYPTION_KEY [CEK_Auto1] ENCRYPTION_TYPE = RANDOMIZED ENCRYPTION_ALGORITHM = 'AEAD_AES_256_CBC_HMAC_SHA_256' COLUMN_MASTER_KEY = CMK_Auto1 ENCRYPTED_VALUE = 0x016E00...; |
Always Encrypted with Secure Enclaves
SQL Server 2019 introduced enhancements to Always Encrypted in the form of secure enclaves. An enclave is a protected region of memory within SQL Server, where computations on encrypted data can occur without revealing the plaintext data outside the enclave.
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CREATE DATABASE SCOPED CREDENTIAL ekm_cred WITH IDENTITY = 'FIELD_KEY', SECRET = 'SWifpm5GDaRVIQwEbPxI1'; |
Retrieving Always Encrypted Data
When you use Always Encrypted, SQL Server will automatically decrypt your data if it determines that your client has the proper decryption keys. You can retrieve encrypted data the same way you would retrieve unencrypted data.
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SELECT CustomerID, CreditCardNumber FROM dbo.Customers; |
Conclusion
In summary, SQL Server Always Encrypted is a valuable feature that offers robust data protection, providing security for sensitive data, both in transit and at rest. The feature’s integration into the client-side application makes it even more powerful and secures from any potential data breaches from the server-side.