1. A property of a voting system that is designed and deployed to enable voters to obtain a ballot, and mark, verify, and cast it without revealing their ballot selections or selections of language, display and interaction modes to anyone else. This does not preclude the ability of a voter to request assistance under state law.
Source: Election Terminology Glossary - Draft, National Institute of Standards and Technology (NIST), https://pages.nist.gov/ElectionGlossary/
2. The ability to prevent others from determining how an individual voted.
Source: Glossary of terms database, U.S. Election Assistance Commission, https://www.eac.gov/glossary/
3. The assurance that the confidentiality of, and access to, certain information about an entity is protected.
4. The ability of individuals to understand and exercise control over how information about themselves may be used by others.
Source: Explore Terms: A Glossary of Common Cybersecurity Terminology, National Initiative for Cybersecurity Careers and Studies (NICCS), https://niccs.us-cert.gov/about-niccs/glossary