When assessing the risk of 'Prompt Leaking', what is the most important control to implement?
Strict output filtering and instruction separation directly counter prompt leaking by isolating system instructions from user-supplied content, so injected queries cannot extract the underlying prompt. This satisfies the scenario's core constraint: preventing disclosure of confidential system prompts through crafted inputs, rather than merely detecting leakage after exposure.
Why this answer
Prompt leaking occurs when an attacker extracts the system prompt or confidential instructions embedded in an LLM application. The most effective control is strict output filtering combined with instruction separation — keeping system instructions isolated from user input and filtering responses that would reveal them. This directly addresses the exfiltration channel rather than the model's size, transport, or network location.
Exam trap
AAISM often tests the misconception that infrastructure controls (network restriction, encryption, model size) mitigate prompt leaking, when the effective control must operate on the prompt/response content itself.
How to eliminate wrong answers
Option A is wrong because increasing parameter count does not prevent prompt leakage — larger models can still be induced to reveal system prompts through jailbreaks, and scale is unrelated to instruction confidentiality. Option B is wrong because encrypting model output protects data in transit but the leaked prompt is already in plaintext inside the response before encryption, so the attacker decrypts and reads it. Option D is wrong because restricting access to internal IPs only narrows the attacker population; an insider or compromised internal host can still perform prompt leaking, and it does nothing to stop the extraction technique itself.