EO Engineering Learning OS
CORE FOUNDATION · F05
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NON-NEGOTIABLE FOUNDATION · TARGET L3 · 7 days
F05

Security foundations

Make exposure, identity, authority, secrets, encryption and auditability visible in every engineering decision.

01 / CONCEPT MAP

Know what the parts mean.

Learn each concept deeply enough to recognize it, place it in the system and reason about normal and failed behavior.

01

Authentication and authorization

Define it · locate it · observe it · explain its failure mode.

02

Least privilege and separation of duties

Define it · locate it · observe it · explain its failure mode.

03

Secrets and credential lifecycle

Define it · locate it · observe it · explain its failure mode.

04

Encryption in transit and at rest

Define it · locate it · observe it · explain its failure mode.

05

Public/private exposure

Define it · locate it · observe it · explain its failure mode.

06

Patching and vulnerability management

Define it · locate it · observe it · explain its failure mode.

07

Audit evidence and incident containment

Define it · locate it · observe it · explain its failure mode.

02 / SYSTEM FLOW

Trace it end to end.

Identity→Authentication→Policy decision→Authorized resource→Encrypted data→Audit event→review

For every transition: identify input, output, identity, protocol, state, trust boundary, evidence and owner.

03 / GUIDED BUILD

Build, observe and explain.

Documentation and AI are allowed. The engineer must review every output and demonstrate the result from direct evidence.

  1. 01Inventory identities and secrets
  2. 02Remove one embedded credential
  3. 03Reduce an overly broad IAM rule
  4. 04Enforce TLS on an application path
  5. 05Block direct database exposure
  6. 06Enable and inspect audit evidence
  7. 07Run a credential-compromise tabletop
04 / INCIDENT

A credential appears in source history and was used from an unfamiliar address.

Required investigation

State impact → collect evidence → form competing hypotheses → test the cheapest discriminator → isolate root cause → contain → correct → verify.

Evidence pack

Timeline, relevant logs/metrics, failed assumptions, root cause, correction, verification and one prevention action.

AI ownership

AI may suggest causes and commands. The engineer must explain why each check is safe, what result is expected and how the result changes the hypothesis.

05 / DESIGN CHALLENGE

Defend the decision.

Threat-model the three-tier FastAPI system and prioritize controls by likelihood, impact and detectability.

06 / VERIFY, SUBMIT & REVIEW

Submission evidence

Architecture review

  • Explain security foundations without relying on memorized commands.
  • Draw the flow and name what crosses every arrow.
  • Identify the most likely, highest-impact and hardest-to-detect failure.
  • Show the evidence that proves the solution works.
  • Defend one security, reliability and cost trade-off.

Definition of Done

  • Acceptance criteria pass
  • Flow is drawn and explained
  • Security implications considered
  • Logs/metrics checked
  • Failure is tested
  • AI output is understood
  • Runbook is reusable
  • Mentor review passes
07 / MENTOR GUIDE

Do not score memory. Score the engineer’s ability to form a model, collect evidence, make a safe change and defend the trade-off.

1 Cannot explain2 Understands with gaps3 Implements and troubleshoots4 Designs and reviews