01
Network adversaries
Every payload is encrypted in your browser before it leaves your device. The transport layer (TLS) and the application layer (XChaCha20-Poly1305) are both authenticated. The server cannot read your content.
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Security
Security
Verifiable post-quantum architecture.
UltimaOS security rests on standards, not promises. The cryptographic primitives are NIST-standardized and IETF-documented, so the algorithms can be checked independently. The client ships to your browser as an inspectable single-page app; the backend is proprietary, and you can question its behaviour from inside uOS via uAI. The whitepaper documents what we protect against, what we do not, and the explicit residual risks.
01
Overview
What we protect against.
02
Server compromise
The server only stores ciphertext and public keys. A server compromise yields encrypted blobs that are useless without the private keys derived from your passphrase.
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Future quantum adversaries
All authentication and key exchange use NIST-standardized post-quantum primitives (ML-DSA-65, ML-KEM-768). This defeats “store now, decrypt later” attacks by future quantum computers.
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Government compulsion
UltimaOS is built and operated in the EU, on EU infrastructure. The US CLOUD Act does not apply. Under EU law, we can only be compelled to disclose content we have technical access to — which is none.
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Details
What we do not protect against.
01
A compromised device
If your device is compromised (malware, keylogger, physical access by an adversary), the attacker can read your content and impersonate you. We mitigate this with device-level biometric locks and short session timeouts, but we cannot fully prevent it.
02
A weak passphrase
Your private key is derived on your device from your passphrase. A weak passphrase (e.g. “123456”) makes brute force feasible. We enforce a minimum passphrase length, but the choice of passphrase remains yours.
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Metadata
We minimize the metadata the server sees (opaque identifiers, bucketed timing) but we do not eliminate it. Full metadata protection is a long-term engineering goal, not a current feature.
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Key points
How to verify our claims.
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01
Read the whitepaper
The whitepaper documents the cryptographic stack, the threat model, and the architectural choices. It is the source of truth for any security claim made on this site.
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02
Inspect the client
The UltimaOS client runs entirely in your browser — you can inspect the cryptographic code, the key-derivation recipe, and the storage layer directly in your browser's developer tools. We do not ship what we cannot show.
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03
Conduct a penetration test
Enterprise customers are welcome to commission an independent penetration test of their workspace. We provide test environments, threat-model documentation, and engineering contact for the duration of the engagement.
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Frequently asked
Security questions.
Where can I report a security issue?
Short answer
Email patrick@ultimaos.com. For sensitive disclosures, use our PGP key (fingerprint available on the same page). We commit to acknowledge within 24 hours and triage within 72 hours.
Has UltimaOS been independently audited?
Short answer
Not by a commissioned third party. The cryptographic stack (ML-DSA-65, ML-KEM-768, XChaCha20-Poly1305, HKDF-SHA256) is built on NIST-standardized primitives and widely-used, community-reviewed libraries, so the algorithms themselves are open to scrutiny. The client ships to your browser as a standard single-page app, so its implementation can be inspected directly in developer tools; the backend is proprietary.
What is your responsible disclosure policy?
Short answer
We follow coordinated disclosure. Report a vulnerability to patrick@ultimaos.com; we triage within 72 hours and aim to ship a fix within 30 days for critical issues. We credit researchers who report valid issues.
What happens if UltimaOS is acquired?
Short answer
The cryptographic architecture does not depend on any single company. If UltimaOS ceased to exist, the encrypted blobs your devices hold would remain readable by your private key, forever. The operational service would cease; the data would not.