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ALTER DATABASE ENCRYPTION KEY (Transact-SQL)

Alters an encryption key and certificate that is used for transparently encrypting a database. For more information about transparent database encryption, see Understanding Transparent Data Encryption (TDE).

Topic link iconTransact-SQL Syntax Conventions

Syntax

ALTER DATABASE ENCRYPTION KEY
      REGENERATE WITH ALGORITHM = { AES_128 | AES_192 | AES_256 | TRIPLE_DES_3KEY }
   |
   ENCRYPTION BY SERVER 
    {
        CERTIFICATE Encryptor_Name |
        ASYMMETRIC KEY Encryptor_Name
    }
[ ; ]

Arguments

  • REGENERATE WITH ALGORITHM = { AES_128 | AES_192 | AES_256 | TRIPLE_DES_3KEY }
    Specifies the encryption algorithm that is used for the encryption key.

  • ENCRYPTION BY SERVER CERTIFICATE Encryptor_Name
    Specifies the name of the certificate used to encrypt the database encryption key.

  • ENCRYPTION BY SERVER ASYMMETRIC KEY Encryptor_Name
    Specifies the name of the asymmetric key used to encrypt the database encryption key.

Remarks

The certificate or asymmetric key that is used to encrypt the database encryption key must be located in the master system database.

The database encryption key does not have to be regenerated when a database owner (dbo) is changed.

After a database encryption key has been modified twice, a log backup must be performed before the database encryption key can be modified again.

Permissions

Requires CONTROL permission on the database and VIEW DEFINITION permission on the certificate or asymmetric key that is used to encrypt the database encryption key.

Examples

The following example alters the database encryption key to use the AES_256 algorithm.

USE AdventureWorks2008R2;
GO
ALTER DATABASE ENCRYPTION KEY
REGENERATE WITH ALGORITHM = AES_256;
GO