What is 'encryption'?

Encryption is the process of converting information into a code to prevent unauthorized access. This transformation makes the data unreadable to anyone who does not possess the necessary decryption key or algorithm, ensuring that sensitive information remains confidential. This technique is fundamental in protecting data during transmission or while it is stored, as it safeguards against interception and unauthorized viewing.

The other options describe different concepts within information technology but do not accurately define encryption. Compressing data, for example, refers to reducing the file size for storage efficiency, while creating a duplicate of a file refers to making backups for data safety. Transferring a file over a secure connection highlights a method of ensuring data security during the transmission process, but it does not inherently involve the act of encrypting the data itself.