Chapter 2 · Build and stress

Poisoning, evasion, extraction, and LLM threats

Use poisoning, evasion, extraction, and llm threats to move the responsible ml production brief toward a defensible release.

65–90 min4 key conceptsReviewed 26 Aug 2026
01 · Production proposition

A high-performing system creates subgroup harm and leaks sensitive information.

This lesson isolates poisoning, evasion, extraction, and llm threats as one decision inside that system. The people affected are product users and operators; the learning data must carry event time, availability time, ownership, and version; and the operating envelope is risk-tiered human oversight.

Decision

Choose whether and how to use differential privacy at a declared prediction cutoff.

Metric

Measure decision utility alongside calibration, slice reliability, and system latency—not model score alone.

Failure consequence

A high-performing system creates subgroup harm and leaks sensitive information. An unsafe release must degrade to a named baseline or the last known-good version.

02 · Intuition & prerequisites

Build the mental model before the machinery.

The core move is to treat poisoning, evasion, extraction, and llm threats as a contract between data, a computation, and an action. Governance evidence must travel with the exact model, data, policy, and runtime release throughout its lifetime. The implementation becomes easier to debug once you can state which inputs exist, which state is learned, what output means, and what must remain invariant after serialization.

01

differential privacy

Define it in a hand-checkable form and name the prediction-time inputs.

02

model supply chain

Connect it to the production metric and identify what it cannot guarantee.

03

prompt injection

Stress it with a slice, a temporal boundary, and a failure-safe alternative.

04

recourse

Stress it with a slice, a temporal boundary, and a failure-safe alternative.

Bring forward

Lessons 1, 2, 3 in this course.

03 · Formal treatment

Name every symbol. Check every shape.

Differential privacy guarantee is the central invariant for this lesson. The formula is useful only when its inputs match the production cutoff and its output maps to an action.

Formal treatment
Pr[M(D)S]exp(ε)Pr[M(D)S]+δ\Pr[M(D) \in S] \le \exp(\varepsilon)\Pr[M(D') \in S] + \delta

Differential privacy guarantee

Symbol, shape or unit contract
SymbolMeaning / shape / unit
Mrandomized mechanism
D, D′adjacent datasets
ε, δprivacy-loss parameters
Open derivation and numerical substitution

Start from the production quantity being optimized, substitute the observed values with their declared units, then isolate the model-controlled term. Preserve shape annotations at each step so broadcasting or aggregation cannot silently change the result.

  1. Write the named inputs: M, D, D′, ε, δ.
  2. Substitute one small, hand-checkable batch before vectorizing.
  3. Calculate an independent reference value and compare within a declared tolerance.
# equation → code contract
inputs = validate_shapes_and_units(batch)
value = compute_c20(inputs)
assert is_finite(value)
04 · Three views of the idea

Calculate it small. Shape it realistically. Break it on purpose.

HAND-CALCULATED TOY

A result you can reproduce on paper

Two thresholds have equal overall accuracy but very different true- and false-positive rates by group.

  1. Write every input and unit.
  2. Substitute values into the differential privacy guarantee equation above.
  3. Compare the result to one simple baseline and explain the direction of the difference.
PRODUCTION-SHAPED

The same reasoning under real constraints

A controlled underwriting pilot uses subgroup analysis, retention controls, signed artifacts, human review, and appeals.

The production record includes the data snapshot, transformation state, artifact identity, cutoff, score, decision, and the version of the policy that consumed it.

FAILURE / COUNTEREXAMPLE

The attractive result you should reject

The team reports one aggregate fairness number, deletes the protected field, loads an untrusted pickle, and logs sensitive inputs forever.

Diagnostic: replay the smallest failing slice from immutable inputs, then compare each boundary rather than retuning the model.

05 · Deterministic lab

Change one assumption and make the tradeoff visible.

This lab runs predefined TypeScript only. It never executes learner code. Use the slider, numeric input, reset, live text, or table—the computation is the same.

Exact computation

Threshold parity lab

Move one group threshold and inspect error-rate and utility tradeoffs.

Primary0.50 TPR gap
Secondary0.00 FPR gap
DiagnosisMaterial disparity

Assumption: Fixed score/label table with different group base rates; group A threshold is 0.5.

Open nonvisual data table
ItemComputed stateInterpretation
A0.50TPR 1.00 / FPR 0.33
B0.50TPR 0.50 / FPR 0.33
06 · Production implications

Trace the complete operating path.

  1. 01

    Validate and version differential privacy.

  2. 02

    Compute poisoning, evasion, extraction, and llm threats from prediction-time-safe inputs.

  3. 03

    Persist model, feature, and configuration identities together.

  4. 04

    Serve or materialize behind explicit risk-tiered human oversight.

  5. 05

    Join telemetry to mature outcomes and retain a rollback path.

Observability

Join service health, input quality, prediction distributions, slice behavior, and mature outcomes by exact version.

Cost

Measure storage, preprocessing, compute, queueing, and human review under a representative arrival pattern.

Failure modes

The team reports one aggregate fairness number, deletes the protected field, loads an untrusted pickle, and logs sensitive inputs forever. Add a detector, owner, mitigation, and stop condition for this class of failure.

Alternatives

Compare a rule, a simpler statistical baseline, and a different system boundary before adding model complexity.

07 · Check understanding

Explain the contract, not just the vocabulary.

Browser-graded checkpointPass ≥ 80%
01Does demographic parity prove fairness?
02Why not delete protected attributes?
03Why is untrusted model serialization dangerous?
08 · Apply in production

Model assurance package

Produce intended-use, fairness, privacy, security, human-review, monitored-rollout, and release evidence.

  • Model/data cards
  • Intersectional analysis
  • Privacy/retention plan
  • Threat model and recourse
Open assignment and rubric
09 · Sources & next depth

Read primary material with a purpose.

10 · Production resolution

Return to the opening failure.

Governance evidence must travel with the exact model, data, policy, and runtime release throughout its lifetime.

For this lesson, the release evidence is a hand-checked formal result, deterministic simulation output, a ≥80% checkpoint, the production rubric, and a named fallback. The course resolves when the system can produce a launch review covering fairness, privacy, licensing, abuse, security, and response.