Your files.
Their future.
ChronoCypher lets you encrypt important files in your browser and store them permanently on the blockchain. When the time comes, your heirs receive everything, automatically.
Only you have the password. We store the encrypted package but cannot see what’s inside, we never have access to your key or your files.
Family Vault
Created Mar 14, 2026
How it works
Set it up once. Never worry again.
Everything runs in your browser. No software to install, no data leaves your device unencrypted.
01
Sign in with email
We send a secure magic link to your inbox. No passwords, no accounts to manage.
02
Configure your vault
Choose a Dead Man's Switch or a fixed date. Add heirs with their name, email, and phone number.
03
Upload & encrypt
Drag your files in. They're encrypted with AES-256-GCM (chunked, streamed from disk) right in the browser before anything leaves your device.
04
Pay once, stored forever
One payment covers permanent storage on Arweave. No subscriptions, no renewals. Your heirs get notified when the vault unlocks.
Possible use cases
If it matters to you later (and you want it private today), this is built for that.
- Will, letters, and end-of-life instructions
- Guardianship and family-care documents
- Medical directives and important health records
- Cryptocurrency wallet recovery phrases and backups
- Account recovery details you only want released after unlock
- Important taxes, insurance, and business records
- Family photos, videos, and personal keepsakes
- A contingency “future you” package for a fixed date or Dead Man's Switch
Security
How your data stays private
Encryption and keys stay in your browser. We only ever handle an opaque, encrypted package — we cannot open it or see what's inside.
1. Only you have the key
The decryption password is generated in your browser and never sent to us. You save it and share it with heirs separately (e.g. in your will or a safe).
2. We only store the lockbox
Your files are encrypted (AES-256-GCM) in the browser. We receive and store only the encrypted blob, we have no key to open it, we cannot see filenames or contents.
3. Heirs need your key to open it
When the vault unlocks (fixed date or Dead Man's Switch), we notify your beneficiaries and give them the sealed package. They can only open it with the password you gave them, we still cannot.
Technical details: AES-256-GCM, Argon2id key derivation, client-side only. Encrypted data is stored on Arweave with no identifying tags (opaque binary only). Random padding slightly obscures exact payload size. Your Legacy Certificate helps you keep the decryption key offline.
What we can and cannot do
- Password loss. If you lose the decryption password and did not share it with your heirs, no one can recover the files — including us. Plan for that the same way you would for any offline safe.
- This browser, this device. While you are creating a vault, the encrypted package may live in your browser storage until you pay. Clearing site data, using another browser, or another computer can break “resume checkout” unless you still have the same encrypted blob.
- What we see. We can see account email, billing, vault status, and encrypted blob metadata needed to run the service. We cannot decrypt your files or list their names or contents inside the package.
- On-chain footprint. The ciphertext is stored on Arweave; uploads avoid app-specific tags so the transaction does not advertise “this is ChronoCypher.” The publishing wallet is still visible on the network like any upload.
Pricing
One payment. No expiration.
Your vault is stored on the blockchain permanently. There are no monthly fees, no renewals, and no risk of data loss from a company shutting down.
- Military-grade encryption
- Permanent Arweave storage
- Dead Man's Switch monitoring
- Printable Legacy Certificate
- Automatic email notifications
- Zero-knowledge, client-side only
- Fixed date or DMS unlock
- Unlimited beneficiaries
- 200+ year storage guarantee
- Optional: physical stainless steel box with M-Disk (200+ year durable)
Starting at
Final price scales with file size. No hidden costs.
Create your vaultNo credit card needed to start
ChronoCypher is a product of DAPP CDN LTD, the company behind dappcdn.com. Billing for this service is processed by DAPP CDN LTD.
7-day money-back guarantee for our service fee. Arweave storage/network costs are non-refundable once published.
Optional: physical archive
For an extra $500 you can add a stainless steel box with an M-Disk. We write your encrypted data to the disk and ship the box to you; you just keep it safe. The box and M-Disk are designed to resist at least 200 years. You can choose this option when creating your vault.