If It Leaks,
You'll Know Exactly Who.
Every document you share is watermarked to whoever opens it. Every note you burn disappears before anyone else can. Try it right here; no account needed.
CLICK OR DRAG FILE HERE
Up to 25MB
A Leaked Draft Costs the Deal.
A Leaked Note Costs Your Name.
Cloud storage assumes every recipient keeps their word. NO SUS is built for when they don't, with a way to find out who broke it, or a way to make sure there's nothing left to leak at all.
Three Jobs. One Platform.
Prevent
Expiring links, view limits, and device checks close the door before a leak happens.
Detect
Every open, download, and blocked screenshot lands in a tamper-evident timeline.
Prove
Every viewed copy is watermarked to the person who opened it, so a leak traces back to exactly one name.
Experience the Vault
Toggle security controls to see how NO SUS enforces data sovereignty in real-time.
Midterm_Notes_Draft.pdf
Unit 4: Signals & Systems. Sampling theorem: a band-limited signal can be perfectly reconstructed when sampled above the Nyquist rate. Aliasing occurs below it; anti-aliasing filters must precede the sampler. See worked examples 4.2-4.6 before Friday's review session.
End-to-End Governance
Upload
Drag or select your document. Files are encrypted client-side using AES-256 before reaching the server.
Protect
Apply dynamic email watermarks, toggle touch-to-reveal blur, and enable root-detection filters.
Share
Mint secure access URLs. Control links with automatic revocation bounds, view counts, and expiration limits.
Collaborate
Roster students or researchers into secure groups. Keep notes sync'd in real-time, online or offline.
Track
Monitor opens, durations, and suspicious actions like right-clicks or screenshot attempts on a chained log.
Control
Instantly revoke share permissions or self-destruct documents, wiping them from cache and storage.
Where a Leak Actually Costs Something
Scenarios the product is built for, not customer testimonials.
Sharing preprint drafts with external reviewers is nerve-wracking. Dynamic watermarking ties every viewed page to the reviewer it was sent to, so a leaked draft is traceable pre-publication.
Researchers
Preprints · Peer Review · Lab NotesStudy groups share draft solutions and notes. Touch-to-reveal blur prevents passive drive-by copying, and the group audit ledger shows exactly who opened what, when.
Study Groups
Notes · Solution Sets · SlidesAfter a client presentation, revoke access to the deck instantly. Expiry windows and view limits keep shared material under your control after it leaves your hands.
Independent Consultants
Decks · Proposals · Contracts
Meet Lux & Nox.
Two cats, one mark. Inside the app they are living characters with a 19-mood animation language, from a breathing idle loop to a sentinel guard stance, driven by what is actually happening to your documents. And they respect your reduced-motion settings, always.
LUX
The Light GuideCurious · Encouraging · Observant
Your workspace navigator and study-desk companion. Lux keeps you oriented, pointing through onboarding, celebrating finished uploads, waiting patiently beside long jobs.
NOX
The Dark GuardProtective · Quiet · Alert
The silent security sentinel. Nox appears at high-security moments, standing guard over the vault, flashing alert when a screenshot is blocked, stamping watermarks as documents are viewed.
Why Not Just Use Google Drive?
Google Drive is good at plenty of things. Tracking who leaked a file isn't one of them.
| Capability | Google Drive | NO SUS |
|---|---|---|
| Works without the recipient having an account | Only with basic link sharing, no tracking | Every time, with full tracking |
| Shows exactly who opened it | Not by default | Identity-watermarked automatically |
| Tamper-evident activity log | Basic activity view | Hash-chained, independently verifiable |
| Content that deletes itself after one view | Not available | Built in |
| Source code you can actually audit | Closed source | Fully open source |
Trust Built on
Proof, Not Promises.
We leverage browser sandboxes, local key storage, and cryptographically verified activity audits to secure your documents.
Private by Design
Access bounds are monitored without user signup requirements.
Zero Knowledge
Encryption keys are held in URL fragments and never touch the host server.
Tamper Ledgers
Activity lists are cryptographically chained to prevent administrative edits.
Secure Send
Custom access expiration options and download locks keep files in your custody.
Every Control,
In Detail.
Secure File Sharing
Encrypt documents in-browser and share them via expiring, view-limited URLs without recipient signups.
Study Groups
Assemble teams, sync documents, and set user permissions with complete RLS access boundaries.
Forensic Watermarks
Render diagonal grid watermarks identifying the viewing recipient, discouraging external captures.
Activity Timeline
Trace all document opens, downloads, and blocked leak attempts in a tamper-evident audit ledger.
Device Verification
Block accesses from emulators, root-broken devices, or browser inspection panels automatically.
Offline Access
Work seamlessly with local storage syncing notes and logs securely once connection is restored.
Version History
Review past document revisions and audit changes chronologically in the system ledger.
Instant Sharing
Generate short-lived anonymous links instantly for quick peer review checks.
Secure Everywhere
Available as a web client or native application. Perfect for tablets, laptops, and mobile screens.
Absolute Governance.
No Excuses.
Only the people you choose can access your files.
Dynamic domain filters and strict user authentication keep document scopes private.
Every action is traceable.
Screenshot logs, DevTools notifications, and dynamic identification watermarks identify source breaches.
Sharing stays under your control.
Instant revocation and view counters close remote access links immediately.
Privacy isn't optional.
From onboarding checks to ledger chains, we bake security directly into every database state.
For Burn Notes and Burn Files, encryption happens entirely in your browser and the key never reaches our servers, managed via the URL hash segment instead. Other shared documents are protected by strict access-control policies rather than end-to-end encryption.
Open Mechanics.
No Trust Required.
Security claims you can check, not marketing copy. These are the actual link format, claim semantics, and ledger construction used in production. The client is open source, so every one of them is inspectable.
# A real Burn Note link, piece by piece:
https://nosus.foo/#/burn/<uuid>?k=<key>&v=<iv>
│ │ │ │
│ │ │ └─ 128-bit AES IV (32 hex chars)
│ │ └─ 256-bit AES key (64 hex chars)
│ └─ note id, the ONLY part the server knows
└─ URL fragment: browsers never send anything after
"#" over the network, so the key and IV exist
only in your and your recipient's browsers.
# The ciphertext in the database is useless without the
# fragment: the server cannot decrypt what it stores.One Person, Directly Accountable.
Shubham Sahu
Design · Code · Security · OpsNO SUS is designed, built, and operated end-to-end by one developer: the Flutter client, the Postgres schema and its row-level-security policies, the edge functions, the cryptography, the CI pipeline, and this page. No growth team, no tracking SDKs, no investors to please.
The architecture is deliberately zero-budget: everything rides on free tiers, which forces the kind of design honesty this product preaches. The server stores ciphertext it cannot read, deletes it atomically on first view, and keeps a hash-chained ledger nobody can quietly edit. The entire client is open source; check the claims yourself.