Disk encryption software
Disk encryption generally refers to wholesale encryption that operates on an entire volume mostly transparently to the user, the system, and applications. This is generally distinguished from file-level encryption that operates by user invocation on a single file or group of files, and which requires the user to decide which specific files should be encrypted. Disk encryption usually includes all aspects of the disk, including directories, so that an adversary cannot determine content, name or size of any file. It is well suited to portable devices such as laptop computers and thumb drives which are particularly susceptible to being lost or stolen. If used properly, someone finding a lost device cannot penetrate actual data, or even know what files might be present.
Column level encryption
Generally, when data are being collected and stored as records, those records will appear in a tabular format in rows in the database with each rows logging specific attributes. Some data can be more sensitive than others, for example, data of birth, social security number, home address, etc., which can act as a personal identification. In order to ensure that these private information is transferred and stored securely, data goes through encryption, which is the process of encoding plaintext into ciphertext. Non-designated readers or receivers will not be able to read the data without the decryption key. Another example to illustrate this concept is, given a database stores client's phone numbers. The set of phone numbers will appear to most readers as gibberish alphanumerical text with a mix of symbols, totally useless to those who do not have access privilege to view the data in plaintext (original form).