octo handles cryptographic seed material and signs blockchain transactions. We take security seriously and appreciate responsible disclosure.

Do not open a public GitHub issue for security reports.

Email security@octo.example (replace with the real address) with:

• a description of the issue and its impact,
• steps to reproduce or a proof of concept,
• any suggested remediation.

We aim to acknowledge within 48 hours and to provide a remediation timeline within 7 days. Please give us a reasonable window to fix the issue before public disclosure.

In scope: key management, the signing path, seed encryption, deposit attribution, withdrawal authorization, webhook signing, and API authentication.

• The HD seed is stored AES-256-GCM encrypted at rest with a random nonce + salt; the master key comes from a KMS/secret manager (an env var only in development).
• The seed is decrypted in-memory only, inside the wallet-core crate, at signing time, and is zeroized immediately after. It is never written to disk or logs.
• Private keys are derived on demand (SEP-0005) and never persisted.

See docs/architecture.md for details.

Some controls only hold if the deployment is configured correctly. The following assumptions are documented in full, with their owners and verification checks, in docs/threat-model.md.

• Trusted proxies — the deployment operator owns TRUSTED_PROXY_CIDRS and must keep it in sync with the real ingress CIDRs. If it is wrong, client IPs (and therefore rate-limit keys) can be spoofed via X-Forwarded-For.
• Rate limiting — the deployment operator must set RATE_LIMIT_BACKEND=postgres in any multi-replica deployment. The default per-process limiter only enforces limits per replica, so the effective limit scales with replica count.
• CORS — the deployment operator owns ALLOWED_ORIGINS and must list exact origins; * is never acceptable for an authenticated API.
• Code paths — the API team owns the limiter and CORS implementations and the checks that verify these assumptions at deploy time.

See docs/threat-model.md for the full assumptions and their verification checks.