What Proton Drive does well
It is worth being clear up front: Proton Drive is a good product. Proton is a mature company with a real track record in privacy tooling, its apps are end-to-end encrypted and zero-knowledge, and its cryptography has been through external audits. Files are encrypted on your device before they reach Proton's servers, so Proton cannot read them. That is the right architecture, and Proton has shipped it for years.
It also comes with an ecosystem. Proton Mail, Proton VPN, and Proton Calendar share one account and one privacy posture, which is genuinely useful if you want encrypted mail, a VPN, and storage from a single vendor you already trust.
If that is what you are looking for, Proton Drive is a reasonable default. The rest of this page is about the specific cases where a different set of tradeoffs fits better.
Why people look for an alternative
People who already trust Proton still come looking for an alternative, usually for one of a few concrete reasons:
- Post-quantum protection on stored files. They want files encrypted today to stay confidential even against a future quantum computer, not only against present-day attackers.
- EU data residency. Their compliance requirement, or their clients' expectations, point to data being stored inside the EU under EU and GDPR jurisdiction, rather than in Switzerland.
- An open, checkable storage cipher. They want to read the exact code that encrypts their files, not accept a description on faith.
- A focused storage product. They want a tool that does encrypted storage well, rather than a suite where storage is one component among several.
None of these are knocks on Proton. They are requirements Proton does not optimize for, and where a different product can.
Where ShieldFive differs
ShieldFive is a storage product that differs from Proton Drive in a few specific, checkable ways.
Post-quantum by default on stored files. ShieldFive defaults every new upload to a post-quantum hybrid suite: ML-KEM-1024 (FIPS 203) combined with a classical cipher, so a break in either component alone does not expose the file. As of June 2026, Proton's post-quantum support ships in Proton Mail (OpenPGP v6) as an opt-in feature; Proton Drive's storage format does not use post-quantum encryption.
This matters because of "harvest now, decrypt later." An adversary can copy encrypted files today and simply wait — storing the ciphertext until a quantum computer capable of breaking classical key exchange exists, then decrypting it retroactively. Files with a long confidentiality lifetime — legal records, medical data, source material, trade secrets — are exposed to that strategy the moment they are uploaded. Post-quantum encryption at upload time is the only point where you can close that window. You cannot retrofit it onto data an adversary already holds.
EU jurisdiction and EU hosting. ShieldFive operates under EU jurisdiction and stores encrypted data in the EU. Proton is based in Switzerland. Both are privacy-friendly homes — Swiss privacy law is strong, and this is not a case of one being safe and the other not. The distinction is narrower: if your requirement is European data residency for a GDPR-driven buyer, a DPO sign-off, or a client contract that specifies the EU, then EU hosting is the cleaner answer to that specific question. If that is not your requirement, it is not an advantage.
An open-source crypto core. ShieldFive's encryption core is published under Apache-2.0 — the same code that runs in your browser. The specification and test vectors are public, and the package you depend on is the package you can read; you can diff the published source against what ships. The point is not that open source is automatically more secure, but that you do not have to take the encryption on description. You can check it.
No AI training and no scanning. ShieldFive does not train models on your files and does not scan their contents. This is not a policy to take on trust — it is a property of the architecture. Because files are encrypted on your device before upload and the server only ever holds ciphertext, there is nothing readable to train on or scan in the first place. A promise can be revised; an architecture that never sees plaintext cannot quietly start reading it.
Pricing. ShieldFive's free tier is 20 GB with no card required. Shield+ is 2 TB at €2.75/month billed every three years, €6.67/month billed annually, or €7.99 billed monthly. Compare against Proton's current plans directly, since both vendors change pricing over time.
Where Proton is ahead, honestly
A fair comparison has to run both ways, so here is where Proton Drive is the stronger choice today.
Audits. Proton Drive has been through external security audits. ShieldFive's crypto core is open and readable, but it has not yet completed a third-party audit — that audit is planned, not done. If an independent audit is a hard requirement right now, that is a real point in Proton's favour, and worth stating plainly rather than implying a parity that has not been earned.
Breadth. Proton is a suite. Mail, VPN, and Calendar come with the account, under one privacy posture and one bill. ShieldFive is storage only — it does encrypted file storage and sharing, and nothing else. If you want one vendor to cover mail, VPN, calendar, and storage together, Proton covers more ground.
If you need an audited, all-in-one privacy suite today, Proton is the stronger pick.
Which one fits you
Proton Drive fits you if you want a single, audited privacy suite — mail, VPN, calendar, and storage from one trusted vendor — and Swiss jurisdiction works for your requirements. It is mature, externally reviewed, and broad.
ShieldFive fits you if storage is the thing you most need to get right, and your priorities are post-quantum protection on stored files by default, EU data residency, and an open crypto core you can read and verify. It is focused, EU-hosted, and built for the long-confidentiality-lifetime case.
Try it
The way to evaluate this is in practice. ShieldFive's free tier is 20 GB with no card, enough to test the workflow with non-critical files first — upload, share with expiry, revoke — before moving anything that matters. Migration is a risk-tiering decision: move the highest-sensitivity files first, the ones where post-quantum protection or EU residency actually changes the exposure, and leave the rest wherever it already works.
This comparison reflects each vendor's public documentation as of 2026-06-09 and will be updated as the products change.