What does it mean when data is encrypted?

When data is encrypted, it is transformed into a format that is unreadable without the appropriate decryption key. This process ensures that even if unauthorized individuals gain access to the data, they cannot interpret it without the key needed to revert it back to its original, readable form. Encryption is a critical aspect of data security, as it protects sensitive information during storage and transmission, ensuring confidentiality and integrity against threats like eavesdropping or data breaches.

The other options describe processes related to data management and transmission but do not pertain directly to encryption. For instance, compressing data focuses on reducing the file size for storage efficiency, dividing data into smaller packets relates to how data is structured for transmission over networks, and backing up data involves creating copies to prevent loss. Each of these processes serves different purposes but does not ensure the same level of security that encryption provides.