This topic describes how to encrypt a column of data by using symmetric encryption in SQL Server 2012 using Transact-SQL.
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Security - To encrypt a column of data, using Transact-SQL
Security
Permissions
The following permissions are necessary to perform the steps below:
- CONTROL permission on the database.
- CREATE CERTIFICATE permission on the database. Only Windows logins, SQL Server logins, and application roles can own certificates. Groups and roles cannot own certificates.
- ALTER permission on the table.
- Some permission on the key and must not have been denied VIEW DEFINITION permission.
To encrypt a column of data using a simple symmetric encryption
- In Object Explorer, connect to an instance of Database Engine.
- On the Standard bar, click New Query.
- Copy and paste the following example into the query window and click Execute.
USE AdventureWorks2012; --If there is no master key, create one now. IF NOT EXISTS (SELECT * FROM sys.symmetric_keys WHERE symmetric_key_id = 101) CREATE MASTER KEY ENCRYPTION BY PASSWORD = '23987hxJKL95QYV4369#ghf0%lekjg5k3fd117r$$#1946kcj$n44ncjhdlj' GO CREATE CERTIFICATE Sales09 WITH SUBJECT = 'Customer Credit Card Numbers'; GO CREATE SYMMETRIC KEY CreditCards_Key11 WITH ALGORITHM = AES_256 ENCRYPTION BY CERTIFICATE Sales09; GO -- Create a column in which to store the encrypted data. ALTER TABLE Sales.CreditCard ADD CardNumber_Encrypted varbinary(128); GO -- Open the symmetric key with which to encrypt the data. OPEN SYMMETRIC KEY CreditCards_Key11 DECRYPTION BY CERTIFICATE Sales09; -- Encrypt the value in column CardNumber using the -- symmetric key CreditCards_Key11. -- Save the result in column CardNumber_Encrypted. UPDATE Sales.CreditCard SET CardNumber_Encrypted = EncryptByKey(Key_GUID('CreditCards_Key11') , CardNumber, 1, HashBytes('SHA1', CONVERT( varbinary , CreditCardID))); GO -- Verify the encryption. -- First, open the symmetric key with which to decrypt the data. OPEN SYMMETRIC KEY CreditCards_Key11 DECRYPTION BY CERTIFICATE Sales09; GO -- Now list the original card number, the encrypted card number, -- and the decrypted ciphertext. If the decryption worked, -- the original number will match the decrypted number. SELECT CardNumber, CardNumber_Encrypted AS 'Encrypted card number', CONVERT(nvarchar, DecryptByKey(CardNumber_Encrypted, 1 , HashBytes('SHA1', CONVERT(varbinary, CreditCardID)))) AS 'Decrypted card number' FROM Sales.CreditCard; GO
To encrypt a column of data using symmetric encryption that includes an authenticator
- In Object Explorer, connect to an instance of Database Engine.
- On the Standard bar, click New Query.
- Copy and paste the following example into the query window and click Execute.
USE AdventureWorks2012; GO --If there is no master key, create one now. IF NOT EXISTS (SELECT * FROM sys.symmetric_keys WHERE symmetric_key_id = 101) CREATE MASTER KEY ENCRYPTION BY PASSWORD = '23987hxJKL969#ghf0%94467GRkjg5k3fd117r$$#1946kcj$n44nhdlj' GO CREATE CERTIFICATE HumanResources037 WITH SUBJECT = 'Employee Social Security Numbers'; GO CREATE SYMMETRIC KEY SSN_Key_01 WITH ALGORITHM = AES_256 ENCRYPTION BY CERTIFICATE HumanResources037; GO USE [AdventureWorks2012]; GO -- Create a column in which to store the encrypted data. ALTER TABLE HumanResources.Employee ADD EncryptedNationalIDNumber varbinary(128); GO -- Open the symmetric key with which to encrypt the data. OPEN SYMMETRIC KEY SSN_Key_01 DECRYPTION BY CERTIFICATE HumanResources037; -- Encrypt the value in column NationalIDNumber with symmetric -- key SSN_Key_01. Save the result in column EncryptedNationalIDNumber. UPDATE HumanResources.Employee SET EncryptedNationalIDNumber = EncryptByKey(Key_GUID('SSN_Key_01'), NationalIDNumber); GO -- Verify the encryption. -- First, open the symmetric key with which to decrypt the data. OPEN SYMMETRIC KEY SSN_Key_01 DECRYPTION BY CERTIFICATE HumanResources037; GO -- Now list the original ID, the encrypted ID, and the -- decrypted ciphertext. If the decryption worked, the original -- and the decrypted ID will match. SELECT NationalIDNumber, EncryptedNationalIDNumber AS 'Encrypted ID Number', CONVERT(nvarchar, DecryptByKey(EncryptedNationalIDNumber)) AS 'Decrypted ID Number' FROM HumanResources.Employee; GO
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