Which cybersecurity method prevents unauthorized users from accessing readable data?

Encryption is the process of converting readable data (plaintext) into an unreadable format (ciphertext) using an algorithm and a cryptographic key. Only individuals with the correct decryption key can revert the ciphertext back to its original, readable form. This method directly prevents unauthorized users from understanding the data's content, even if they manage to gain access to the file or storage medium itself. It is a fundamental control for ensuring data confidentiality both at rest (stored) and in transit (being transmitted).

A. Steganography: This method focuses on concealing the existence of data within another file or medium, not on making the data itself unreadable. If discovered, the hidden data is typically in its original, readable format.

B. Data masking: This technique creates a structurally similar but inauthentic version of data, primarily for use in non-production environments like testing or training. It protects the original data by replacing it, not by making it unreadable to unauthorized users in a live system.

C. Access control lists (ACLs): ACLs are a form of authorization that determines who is allowed to access a specific file or resource. They prevent access to the data object but do not protect the data's readability if the access controls are bypassed (e.g., physical theft of a hard drive).

1. National Institute of Standards and Technology (NIST). (2020). Special Publication (SP) 800-53 Rev. 5: Security and Privacy Controls for Information Systems and Organizations. Section: SC-28 Protection of Information at Rest. The control description states

"The information system protects the confidentiality and integrity of the following information at rest: [Assignment: organization-defined information at rest]" often through the use of encryption.

2. Saltzer

J. H.

& Schroeder

M. D. (1975). The Protection of Information in Computer Systems. Proceedings of the IEEE

63(9)

1278–1308. (A foundational academic paper referenced in many university security courses). Section I.B.3

"Cryptographic Sealing

" describes encryption as a primary method for ensuring privacy against unauthorized reading. Available via MIT's DSpace: https://dspace.mit.edu/handle/1721.1/46463

3. Perrig

A.

& Song

D. (2014). MIT OpenCourseWare 6.858 Computer Systems Security

Fall 2014. Lecture 1: Introduction & Threat Models. The lecture notes differentiate between access control mechanisms (which can fail) and cryptography (encryption) as a method to protect data content regardless of access.

4. Kaur

M.

& Singh

A. (2014). A Review of Data Masking as a Tool for Data Protection. International Journal of Advanced Research in Computer Science and Software Engineering

4(1)

818-821. This paper defines data masking as a process of "hiding original data with modified content (characters or other data)

" primarily for creating safe test data

distinguishing it from encryption for live data protection.

5. Provos

N.

& Honeyman

P. (2003). Hide and Seek: An Introduction to Steganography. IEEE Security & Privacy

1(3)

32-44. https://doi.org/10.1109/MSECP.2003.1203220. This article clarifies that steganography's goal is to hide communication

making it distinct from cryptography

which aims to make communication unintelligible.