Share what matters. Encrypted end-to-end, built to outlast any one person.
Sissare is end-to-end encrypted document sharing designed for the documents families actually need to keep safe and reachable: property certificates, wills, ID records. Nobody but the people you choose can ever read them -- not even us.
Get in touchHow it works
Encrypt on your device
A document is encrypted on your device before it ever leaves it. The encryption key is wrapped individually for each person you authorize -- our servers only ever see ciphertext, never plaintext and never an unwrapped key.
Invite and verify
Share by email or a time-boxed QR code. Every join request is checked by hand against a cryptographic key fingerprint before access is granted -- casual sharing, without casual trust.
Access that outlasts one person
Every document can have a designated Successor. If an Owner becomes inactive or deletes their account, ownership transfers automatically -- a family document was never meant to depend on one person staying reachable forever.
Features
Genuine zero-knowledge encryption
Not "encrypted at rest, decrypted for convenience." We structurally cannot read your documents, full stop.
Quantum-safe by design
Hybrid classical + post-quantum key exchange (X25519 + ML-KEM-768), from day one, not a future migration project.
QR invites with real verification
Drop a QR code in the family group chat. Every scan still requires an individual, manual identity check before access is granted.
Built-in succession
A designated Successor for every document means continuity doesn't depend on any single person remaining active or reachable.
Freemium that doesn't ambush you
Plan limits are never enforced by silently breaking access. You're always warned first, with a clear window to act.
Fair, non-punitive collaboration
Storage is billed to the document Owner, never to collaborators who happen to be uploading -- no surprise costs for helping out.
Pricing
Prices below are our US reference pricing. Actual pricing is set per region through the App Store and Google Play, so what you pay reflects local purchasing power, not one flat global price. Feature limits are identical everywhere.
Free
$0
Try it with the documents that matter most.
- 1 GB storage
- Up to 3 collaborators per document
- 200 MB max file size
Plus
$7.99/mo
For a growing family archive.
- 25 GB storage
- Up to 10 collaborators per document
- 2 GB max file size
Family
$14.99/mo
Room for every certificate, deed, and will.
- 100 GB storage
- Unlimited collaborators per document
- 5 GB max file size
Frequently asked questions
Can Sissare read my documents?
No. Every document is encrypted on your device before it ever reaches our servers, using a key that only your device and the people you explicitly authorize can unwrap. We store encrypted bytes and the metadata needed to run the service -- never the content, and never a usable copy of the keys.
Is it really true that a lost document can never be recovered -- not even by you?
Yes, and we want to be upfront about this rather than let it surprise you later. If a document ends up with no remaining key-holder -- no Owner, no designated Successor, no other collaborator -- its content becomes permanently and irreversibly unreadable, by anyone, including us. This is the direct, structural consequence of us never holding your keys, not a bug or a support limitation. Assigning a Successor to anything important is the way to avoid this.
What happens if I lose my device, stop using Sissare, or delete my account?
Every document can have a designated Successor -- a collaborator who automatically becomes the new Owner if you go inactive for an extended period or delete your account. If you never lose access to your own account, nothing changes for you. If you do, and a Successor is configured, your document keeps its custodian without you having to do anything. If no Successor is configured, see the previous answer: the document can become permanently unreadable.
How does the QR invitation actually verify someone’s identity?
Scanning a QR code creates a join request, not instant access. The document Owner sees the requester’s cryptographic key fingerprint and manually approves or rejects the request -- the same idea as a Signal "safety number" check. Nobody gets in automatically just by scanning a code.
What does "quantum-safe" actually mean here?
Keys are exchanged using a hybrid of classical (X25519) and post-quantum (ML-KEM-768, a NIST-standardized algorithm under FIPS 203) cryptography. That means even if a future quantum computer could break the classical half, the post-quantum half still holds -- and vice versa if a weakness is ever found in the newer algorithm. Document content itself is encrypted with XChaCha20-Poly1305. We’d rather over-explain this than let "quantum-safe" read as an empty buzzword: it’s a specific, verifiable design choice.
What happens if I downgrade my plan and a document now has too many collaborators?
You'll be notified immediately, in-app, and given a fixed window to choose exactly which collaborators to keep on that document. If you don't act within that window, every collaborator except you is removed automatically so the document comes back into compliance with your plan -- we never silently pick for you ahead of that deadline, and we never leave the situation unresolved indefinitely.
Do the prices shown above match what I’ll actually pay?
The prices above are our US reference pricing. Actual pricing is set per country/region through the Apple App Store and Google Play, following each store’s own local pricing tiers -- so the price you see when you subscribe reflects your own storefront, not a single flat global number. Feature limits (storage, collaborators, file size) are identical everywhere; only price varies.