Core trust principles
1. Explicit consent (h3)
Users must explicitly approve each sensitive operation. Consent manifests in cryptographic signatures on the device, clear UI text displaying amounts, addresses, and operation details, and audit traces (timestamps, operation hashes). Design your integration so the device is the final arbiter of consent — not the remote service.
2. Minimal exposure (h3)
Limit what your app asks for. Only request signing for required fields; never ask for full private keys or unnecessary permissions. Use ephemeral sessions and rotate any API keys where possible.
3. Deterministic verification (h3)
Provide the user with deterministic, human-readable transaction descriptions. For complex actions (smart-contract interactions), translate low-level parameters into plain language before sending them for device approval.
4. Fail-safe defaults (h3)
Assume the network or third-party may be compromised. Fail closed: if verification fails or the device reports an unknown instruction, abort the operation and surface clear remediation steps to the user.
Technical patterns: Ledger Live integrations
Accounts & Blockchain integration (h3)
Integrations often fall into three buckets: Accounts (supporting new chains/accounts in Ledger Live), Device Apps (firmware apps running on Ledger devices), and Live Apps (web apps surfaced inside Ledger Live). Each type has submission, testing and user verification flows — documented on the Ledger Developer Portal.
Accounts (h4)
Accounts integration exposes balances and transaction history to Ledger Live. Developers typically register their blockchain support, provide RPC endpoints, and follow Ledger’s validation guide. Always provide a testnet endpoint and test vectors for reproducible validation.
Device Apps & SDK (h4)
Device apps (C / Rust) implement transaction parsing and signing on-device. Use the Device App Kit and well-tested cryptography primitives. Keep signing logic deterministic and include comprehensive unit tests — Ledger’s Device App documentation shows the recommended patterns.
Live Apps (h4)
Live Apps run in a sandboxed context and communicate with Ledger Live through defined APIs. They can provide richer UX while handing key operations to the device. Use secure messaging and validate all inputs on both ends.
Developer mode & sandbox (h5)
Always develop against the Ledger sandbox and enable developer mode for local testing. Provide automated test suites that simulate device responses to verify UX flows before submission.
UX: making verification obvious and simple
Clear prompts (h3)
When the device shows a spending amount or contract call, ensure the live app shows the same text and includes a "verify on device" affordance. Use short, layered prompts: summary → details → confirm.
Progress & rollback (h3)
Show transaction state (pending, confirmed, failed) with clear guidance. Provide an easy rollback or cancel where possible and show transaction IDs for external verification.
Accessibility & localization (h4)
Trust is also accessibility: make prompts readable at-a-glance and localize strings for supported markets. Avoid dense technical jargon in approval screens.
Security checklist for submission
- Unit tests for signature flows and edge cases
- Deterministic serialization of transactions
- Proof-of-wallet (displayable verification strings)
- Security posture documentation (threat model, mitigations)
- Contact & incident response path included in docs
Submission deliverables (h5)
Provide clear installation instructions, setup, test vectors and a short non-technical summary that explains why the device/app combination is safe for users. Ledger’s submission docs enumerate required deliverables.
Conclusion & next steps
Building trust into integrations with Ledger Live is a cross-functional effort — product, engineering, security, and legal must align. Focus on explicit consent, minimal exposure, verifiable UX, and solid testing. When in doubt, prefer the device’s judgment: make the hardware wallet the final authority.
Next steps: register your project on the Developer Portal, set up the sandbox, follow device app templates, and schedule a submission review following Ledger’s guidelines.