SQL Server Transparent Data Encryption, also known as TDE, is a “data at rest” encryption mechanism that is introduced in SQL Server 2008 as an Enterprise Edition feature. TDE is used to perform a real-time I/O encryption for the SQL Server database data, log, backup and snapshot physical files, rather than encrypting the data itself, using either Advanced Encryption Standard (AES) or Triple DES (3DES) encryption.
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