eng-security-safety

# Security and Safety Mindset ## Intent - Treat every change as a potential attack surface or failure amplifier. - Ensure data classification, secret handling, and permission scopes stay compliant. - Bake safety checks (rate limits, input validation, monitoring) into the design, not after. ## Baseline Checklist 1. **Threat model quickly**: Who could abuse this surface? What capabilities do they need? What happens if they succeed? 2. **Data stewardship**: Classify data touched (PII, payments, assets) and enforce encryption, retention, and locality rules. 3. **Access + identity**: Validate authn/authz paths, key rotation, wallet signatures, and privilege escalation barriers. 4. **Dependency hygiene**: Pin versions, verify licenses, review changelogs, and prefer audited libraries/contracts. 5. **Secrets + config**: Never log secrets; store them in the project’s approved secret manager. Guard env var usage. ## Workflow 1. Enumerate entry points (mobile UI, API, smart contract, admin tools) and list unchecked inputs. 2. Define validation layers: schema-level, business-level, and environment-level (e.g., chain ID, platform version). 3. Ensure every state change is reversible or compensatable (feature flags, contract pausing, migration guards). 4. Instrument detection: structured logs, metrics, or on-chain events that can surface abuse or regressions fast. 5. Document explicit “never do” actions (e.g., disable signature checks, bypass paywalls) inside the PR/issue notes. ## Verification - Run the project’s security/static analysis tooling (linters, contract analyzers, mobile scanners) and fix findings. - Peer review the threat model summary; confirm secrets and keys are absent from diffs/logs. - Validate abuse cases end-to-end (invalid payloads, replayed signatures, abusive traffic) before shipping.