What is the function of a data encryption key (DEK)?

The function of a data encryption key (DEK) is primarily to encrypt message text and ensure the integrity of the data. This key is essential in the encryption process, transforming plaintext into ciphertext, which can only be decrypted back to plaintext with the corresponding key. In addition to encryption, the DEK often includes mechanisms to compute integrity checks, ensuring that the data has not been altered or tampered with during transmission or storage. By utilizing a DEK, organizations can uphold the confidentiality and integrity of sensitive information, which is crucial for data security in various applications.

The other options do touch upon relevant security concepts, but they do not define the specific function of a DEK. For example, decrypting stored data is not solely the role of a DEK, as it often relates to the associated keys that might be utilized alongside the DEK. Unlocking database access and backing up data securely pertain to broader security and operational themes rather than the specific role of a DEK in data encryption.