SQL Server Transparent Data Encryption (TDE) is a built-in encryption technology that you can encrypt your data without any performance degradation. TDE automatically encrypts the content of all user databases and their backups and log files on disk.
When data is encrypted with TDE, all the original content of the database – including queries and indexes on that data – are transparently encrypted. This ensures that sensitive information cannot be accessed by hackers or unauthorised personnel.
A SQL Server system key protects access to this data at rest, so even if someone does manage to mount an attack against your environment, it would take many years for these attackers to decrypt your data.
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