Which component of information security aims to prevent an attacker from denying that a user performed an action?

Which component of information security aims to prevent an attacker from denying that a user performed an action?

• A. Integrity
• B. Availability
• C. Confidentiality
• D. Nonrepudiation

Answer: (D)

Nonrepudiation is the protection that makes it possible to prove who performed a given action and when, so a user cannot later deny having done it. In practice this relies on cryptographic signatures, authentication, and tamper-evident audit logs. A digital signature binds the action to the signer’s identity and the exact action (including time and content), and the accompanying logs provide verifiable evidence that the action occurred and was authorized. This is distinct from integrity (ensuring data isn’t altered), confidentiality (protecting data from unauthorized access), and availability (ensuring systems and data are accessible). In healthcare, nonrepudiation is crucial for audit trails and legal accountability—if a clinician prescribes or modifies a record, the combination of digital signatures and logs ties that action to the individual and makes denial impractical.

Nonrepudiation is the protection that makes it possible to prove who performed a given action and when, so a user cannot later deny having done it. In practice this relies on cryptographic signatures, authentication, and tamper-evident audit logs. A digital signature binds the action to the signer’s identity and the exact action (including time and content), and the accompanying logs provide verifiable evidence that the action occurred and was authorized. This is distinct from integrity (ensuring data isn’t altered), confidentiality (protecting data from unauthorized access), and availability (ensuring systems and data are accessible). In healthcare, nonrepudiation is crucial for audit trails and legal accountability—if a clinician prescribes or modifies a record, the combination of digital signatures and logs ties that action to the individual and makes denial impractical.