Protecting your digital legacy with uncompromising security.
Everyone accumulates a digital life — passwords, documents, private messages, financial records. But what happens to all of it if you're suddenly gone?
Eternal Sentinel exists to solve this problem. We provide a secure dead man's switch that ensures your most important information reaches the people you trust, but only when it's truly needed.
No one — not even us — can access your vault. Your data stays encrypted and under your control until the moment your trusted contacts need it.
Eternal Sentinel is built on a zero-knowledge model. All encryption and decryption happens entirely on your device — your master password and encryption keys never leave your browser.
Our servers store only encrypted blobs. We have no ability to read, decrypt, or recover your data. Even if our servers were compromised, an attacker would gain nothing but ciphertext that is computationally infeasible to break.
This means you are the sole custodian of your vault. We cannot reset your password or recover your data if you lose it — and that's by design.
You receive periodic check-in reminders via email or SMS on a schedule you choose. A single click confirms you're OK and resets the countdown timer.
If you miss a check-in, Eternal Sentinel escalates — sending additional reminders through multiple channels. This grace period protects against accidental misses, vacations, or temporary unavailability.
After all escalation attempts are exhausted without a response, the protocol activates. Your designated trustees are notified and granted access to the vault items you assigned to them. Any final letters you've prepared are delivered to their intended recipients.
Some things are too important to leave unsaid. Final Letters lets you write personal messages to the people who matter most — a spouse, a child, a lifelong friend — and have them delivered only when the time comes.
Compose as many letters as you need, each addressed to a specific recipient. Your letter contents are encrypted with the same zero-knowledge architecture as your vault, so no one can read them until your protocol activates.
When you're satisfied with a letter, mark it as “Ready.” If the dead man's switch triggers, every ready letter is automatically delivered to its recipient via email. Draft letters are never sent, giving you full control over what gets delivered.
Every vault item is encrypted with AES-256-GCM, an authenticated encryption algorithm that provides both confidentiality and integrity. Each item uses a unique random nonce, preventing any pattern analysis across your stored data.
Your master password is never stored or transmitted. Instead, PBKDF2 derives a high-entropy encryption key from your password using hundreds of thousands of iterations, making brute-force attacks impractical even with specialized hardware.
Each vault item is encrypted with its own randomly generated nonce (number used once). This ensures that even identical plaintext values produce entirely different ciphertext, eliminating any information leakage between items.
All cryptographic operations run in your browser using the Web Crypto API. Your plaintext data and encryption keys exist only in your device's memory and are never sent to our servers.