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Quiz Entry - updated: 2026.07.14

What is Repudiation in STRIDE and what security property does it violate?

Denying you performed an action when you actually did — it violates Non-Repudiation.

Repudiation:

Aspect Description
Property violated Non-Repudiation
Definition Claiming to have not performed an action
Examples "I didn't send that email," "I didn't modify that file," "I certainly didn't visit that website!"

Why it matters: Without proper logging and audit trails, users (or attackers) can deny actions they actually performed.

Mitigation:

  • Secure audit logging
  • Digital signatures
  • Timestamps from trusted sources
  • Transaction logs that cannot be modified

From Quiz: SPRG / SDL and Threat Modeling | Updated: Jul 14, 2026