What is the function of a Data Encryption Key (DEK)?

A Data Encryption Key (DEK) primarily facilitates the encryption and decryption of sensitive data. This key is crucial in safeguarding the confidentiality of information, ensuring that only authorized parties can access the data within encrypted formats. When data is encrypted, the DEK is used to convert plaintext into ciphertext, making it unintelligible to anyone who does not possess the key. Conversely, during decryption, the same key is required to restore the data back to its original, readable state. This dual functionality is fundamental to maintaining data security in electronic transactions and communication.

While the other choices mention key aspects of data security, they do not specifically pinpoint the core role of the DEK. Storing customer information securely encompasses broader data management and security practices. Permanently locking access to information pertains to permanent data protection mechanisms, which differs from the temporary and reversible nature of encryption. Authorizing transactions in real time relates more to transaction processing systems and does not align with the primary function of the DEK. Therefore, the correct answer effectively captures the essence of the DEK's role in the encryption and decryption process.