Sql server and database encryption keys (database engine)

SQL Server has two primary applications for keys: a service master key (SMK) generated on and for a SQL Server instance, and a database master key (DMK) used for a database.

The SMK is automatically generated the first time the SQL Server instance is started and is used to encrypt a linked server password, credentials, and the database master key. Database log horizon The SMK is encrypted by using the local computer key using the Windows Data Protection API (DPAPI). Data recovery raid The DPAPI uses a key that is derived from the Windows credentials of the SQL Server service account and the computer’s credentials. Database design for mere mortals The service master key can only be decrypted by the service account under which it was created or by a principal that has access to the machine’s credentials.


The database master key is a symmetric key that is used to protect the private keys of certificates and asymmetric keys that are present in the database. Database hardening It can also be used to encrypt data, but it has length limitations that make it less practical for data than using a symmetric key.

When it is created, the master key is encrypted by using the Triple DES algorithm and a user-supplied password. Data recovery linux distro To enable the automatic decryption of the master key, a copy of the key is encrypted by using the SMK. Data recovery key It is stored in both the database where it is used and in the master system database.

The copy of the DMK stored in the master system database is silently updated whenever the DMK is changed. Data recovery macbook However, this default can be changed by using the DROP ENCRYPTION BY SERVICE MASTER KEY option of the ALTER MASTER KEY statement. Data recovery los angeles A DMK that is not encrypted by the service master key must be opened by using the OPEN MASTER KEY statement and a password.

Managing encryption keys consists of creating new database keys, creating a backup of the server and database keys, and knowing when and how to restore, delete, or change the keys.

Re-create keys and re-encrypt data in the unlikely event that the key is compromised. Database yml As a security best practice, you should re-create the keys periodically (for example, every few months) to protect the server from attacks that try to decipher the keys.

Add or remove a server instance from a server scale-out deployment where multiple servers share both a single database and the key that provides reversible encryption for that database.

Accessing objects secured by the service master key requires either the SQL Server Service account that was used to create the key or the computer (machine) account. Database in excel That is, the computer is tied to the system where the key was created. G info database You can change the SQL Server Service account or the computer account without losing access to the key. Database book However, if you change both, you will lose access to the service master key. Q prime database If you lose access to the service master key without one of these two elements, you be unable to decrypt data and objects encrypted by using the original key.

If you lose all access to the keys described earlier, you will lose access to the objects, connections, and data secured by those keys. Top 10 data recovery tools You can restore the service master key, as described in the links that are shown here, or you can go back to the original encrypting system to recover the access. Data recovery laptop There is no “back-door” to recover the access.

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