Quantum-safe
cloud storage
for your files
Post-quantum encrypted file storage and document sharing. Upload files of any size to your personal vault — they are encrypted in your browser with ML-KEM before they leave your device, so PQCServer stores only ciphertext it cannot read. Share by shortlink or directly with another user. Free, with no size limits.
Harvest now, decrypt later
The reason to encrypt stored files with post-quantum cryptography today, not when quantum computers arrive.
A quantum computer capable of breaking RSA and elliptic-curve cryptography does not exist yet. That fact is often read as permission to wait. It is not, because the attack against stored data does not require the quantum computer to exist at the time of the attack.
An adversary copies your encrypted files today and does nothing with them. The ciphertext costs almost nothing to archive. When a cryptographically relevant quantum computer becomes available — most estimates put this somewhere between one and several decades out — the archive is decrypted retroactively. This strategy is known as harvest now, decrypt later, and it is why NIST, the NSA and the major cloud providers have all set migration deadlines well ahead of the threat itself.
What follows is a simple rule: a file is at risk from the day it is uploaded, not from the day the quantum computer is built. If the information inside it needs to stay confidential for longer than the remaining life of classical public-key cryptography, encrypting it with RSA or ECC today is already a decision to expose it later. Legal records, medical histories, engineering drawings, journalistic source material, financial models and identity documents all fall on the wrong side of that line.
The same reasoning applies to anything else you transmit or store. PQCServer applies ML-KEM across encrypted messaging, one-off file encryption, document notarisation and cryptographic timestamping — the vault is the permanent-storage half of it.
Encrypt locally. Store securely.
The vault uses the same ML-KEM encryption as encrypted messaging — your files are encrypted before they ever leave your browser.
No file size limits — ever
Files are split into 3MB chunks before upload. Each chunk is uploaded separately, bypassing any per-request size limits from CDN or proxy layers. The server reassembles the chunks server-side.
A complete encrypted drive
Dashboard & File List
View all your vault files in a grid with icons, filename, size, upload date and access stats. Search by name, filter by tag, sort by date or size.
Shortlinks & Sharing
Every vault file gets a shortlink automatically. Generate new shortlinks anytime. Share directly with a registered username — they can download and decrypt with their own key.
Tags & Notes
Organize files with up to 10 tags and an optional note per file. Filter the dashboard by tag to quickly find what you need.
Permanent Storage
Vault files have no TTL — they remain until you explicitly delete them. Unlike messages (which expire), vault files are your permanent encrypted archive.
Clean Deletion
Deleting a vault file removes the GridFS chunks, all associated shortlinks, and the vault entry — completely and immediately. No lingering data.
Storage Stats
Dashboard shows total files, total storage used, and per-file access count. Know exactly what's in your vault and how much space it uses.
PQCServer Vault vs alternatives
Google Drive
- ✗ Google can read your files
- ✗ No post-quantum encryption
- ✓ Large storage limits
- ✓ Good UI and sharing
- ✗ Privacy dependent on Google
PQCServer Vault
- ✓ Zero-knowledge server
- ✓ ML-KEM NIST FIPS-203
- ✓ No file size limits
- ✓ Shortlink sharing
- ✓ Quantum-resistant forever
Proton Drive
- ✓ End-to-end encrypted
- ✓ Strong privacy reputation
- ~ Limited free storage tier
- ~ PQC shipped in Proton Mail (2026)
- ✗ Drive storage not yet post-quantum
Dropbox
- ✗ Provider holds the keys
- ✗ No post-quantum encryption
- ✓ Mature sync and collaboration
- ✓ Wide platform support
- ✗ Files readable server-side
MEGA
- ✓ Zero-knowledge by design
- ✗ RSA/AES — not quantum-safe
- ✓ Generous free tier
- ~ Key handling in the browser
- ✗ No post-quantum storage format
Cryptomator
- ✓ Open source and auditable
- ✓ Works on top of any cloud
- ✗ AES/RSA — not quantum-safe
- ✗ No built-in sharing
- ~ Requires a separate storage provider
Comparison reflects publicly documented behaviour as of 2026 and covers post-quantum protection of files at rest specifically. Every product listed here is competent at what it was built for; the axis being compared is whether stored ciphertext survives a future quantum adversary.
Frequently asked questions
Post-quantum storage, in plain terms.
What is quantum-safe cloud storage?
Quantum-safe cloud storage encrypts your files with algorithms that remain secure even against a large-scale quantum computer. PQCServer Vault uses ML-KEM, standardised by NIST as FIPS-203, to derive the key that protects each file, instead of RSA or elliptic-curve cryptography, which a quantum computer running Shor's algorithm would be able to break.
Why does stored data need post-quantum encryption today?
Because of harvest now, decrypt later. An adversary copies your encrypted files today and stores the ciphertext, waiting until a quantum computer capable of breaking classical key exchange exists, then decrypts everything retroactively. Any file whose confidentiality has to outlive that moment — legal records, medical data, source code, trade secrets — is exposed from the day it is uploaded, not from the day the quantum computer is built.
What is ML-KEM?
ML-KEM (Module-Lattice-Based Key-Encapsulation Mechanism) is the post-quantum key encapsulation standard published by NIST as FIPS-203 in August 2024, derived from the CRYSTALS-Kyber submission. Its security rests on the hardness of the Module Learning With Errors problem, for which no efficient quantum algorithm is known. It replaces the RSA and elliptic-curve key exchange that Shor's algorithm renders breakable.
Can PQCServer read the files I store?
No. Encryption happens in your browser before upload, and your ML-KEM private key is never transmitted to the server. PQCServer stores only ciphertext it has no means of decrypting. This is what zero-knowledge means in practice: the operator cannot read your data even under legal compulsion, because the operator does not hold the key. The technical manual documents the full key handling.
Is there a file size limit?
No. Encrypted files are split into 3MB chunks before upload and reassembled server-side, so no single request approaches the per-request size limits imposed by CDN or proxy layers. A 50MB file uploads as 17 chunks; a 5GB file uploads as roughly 1,700. The chunking is transparent — you upload and download whole files.
How do I share a document securely?
Every file in your vault gets a shortlink automatically, and you can regenerate it at any time to revoke the previous one. You can also share directly with another registered PQCServer user by username, in which case the file is re-encapsulated to their ML-KEM public key so they decrypt it with their own private key. For one-off transfers that should expire on their own, use encrypted messaging instead.
How does PQCServer Vault compare to Proton Drive?
Proton Drive is end-to-end encrypted and zero-knowledge, with a strong privacy track record. The difference is the algorithm: as of 2026 Proton's post-quantum support ships in Proton Mail via OpenPGP v6 as an opt-in feature, while Proton Drive's storage format does not yet use post-quantum encryption. PQCServer Vault applies ML-KEM to every file at rest by default.
How much does it cost?
Nothing. The vault is free, with no file size limit, no storage tier and no paid plan to upgrade to. There is no tracking and no advertising.
Start your quantum-safe vault today
Register, generate your ML-KEM keys, and upload your first encrypted file in under 2 minutes. Free forever.