Encryption is a security measure that protects the confidentiality of data at rest by converting human-readable data into a non-human-readable format. This process makes the data inaccessible to unauthorized individuals without the proper decryption key. Other options, such as hashing or tokenization, are also used for protecting data, but these methods do not typically retain the original format that allows the data to be easily decrypted and read, which is essential for data at rest scenarios where the data may need to be retrieved in its original, human-readable form.