Comparison · Verified July 2026 · Every claim links to its source
ASTIS Mail vs Tuta
Tuta shares our convictions — subjects encrypted, metadata minimized, German servers. It implements them as a closed replacement ecosystem; ASTIS Mail implements them on top of the provider you already run.
TL;DR. Tuta deserves respect: German, open-source, self-funded, encrypting subject lines since before it was fashionable, and first in the category to ship post-quantum hybrid encryption (TutaCrypt, 2024) — their announcement is linked below. Its model is total: Tuta is your provider, with its own protocol and no IMAP at all, by design. That is also the business limitation: closed ecosystem, minimal integrations, migration required. ASTIS Mail draws the same envelope — subjects included — over Gmail and Microsoft 365 instead of replacing them. Privacy-first individuals get excellent value at €6–12/user/month; businesses that can’t leave their provider or their mail clients can’t use Tuta at all.
At a glance
The icon next to a claim opens its primary source — the vendor’s own page for their claims, our verifiable docs for ours. Security platforms shouldn’t ask to be believed.
| ASTIS Mail | Tuta | |
|---|---|---|
| What it is | E2EE client over your existing Gmail / M365 | |
| Subject lines encrypted | ||
| Post-quantum encryption | ||
| Encryption standard | ||
| IMAP / third-party clients | Native apps + Thunderbird add-on; your provider’s clients keep working | |
| Migration required | None — OAuth connect | |
| External recipient (no account) | One-time key invite (browser client) | |
| Org-level key recovery | Org key in CVS — ASTIS-managed or self-hosted (HYOK) | |
| Certifications issued today | ||
| Published pricing |
Where is the trust boundary?
Every product on this market draws a line: everything left of it cannot read your content; everything right of it you have to trust. The only question that matters is where the line sits.
Keys generated and used client-side. No service can produce plaintext.
Content encrypted, but a vendor-run key server authorizes every decryption.
Encryption and access control live in the vendor’s server-side platform.
TLS in transit; content readable at rest by providers and gateways.
Tuta is genuinely device-boundary E2EE — same zone as ASTIS Mail. The boundary that differs is ecosystem: Tuta’s keys and clients work only inside Tuta; OpenPGP keys work in any compliant implementation, and your mailbox stays at your provider.
Where your data lives
ASTIS Mail deliberately does not host message content: decrypted mail exists only on your devices, ciphertext rides your own mailbox. Compare where each product puts plaintext.
Who holds the keys?
ASTIS Mail’s model
The same envelope convictions — subjects encrypted, capsule metadata on address hashes, E2EE calendar — implemented inside your existing provider: Gmail/M365 move envelopes they cannot read.
OpenPGP + WKD instead of a proprietary protocol: keys portable, messages decryptable by any compliant client including GnuPG, and org-key recovery through CVS — ASTIS-managed or customer-hosted (HYOK). Standards were the answer to PGP’s gaps, not a new silo.
Tuta’s model
Own protocol (AES-256 + ECC, TutaCrypt post-quantum hybrid), deliberately not PGP — their stated reasons: PGP leaves subjects unencrypted, upgrades algorithms poorly, lacks forward secrecy. Everything from calendars to search indexes is encrypted inside their apps.
The cost of the closed loop is interoperability: no IMAP is not an oversight but a design decision — and it means no Outlook, no Apple Mail, no CRM integrations, no mail-dependent workflows.
Tuta’s stated reasons for abandoning PGP include that “PGP does not encrypt the subject line” — the same gap ASTIS closes while staying inside the PGP standard.— tuta.com — encryption guide
Post-quantum and the ecosystem wall — the honest section
The wall businesses actually hit
Teams that live in Outlook or depend on integrations cannot adopt a no-IMAP provider — reviews repeat the same three complaints: no IMAP, slow search, few integrations.
Compliance paperwork: German hosting and GDPR marketing, but no company-wide SOC 2 or ISO certificate to hand an auditor, and no HIPAA BAA program. ASTIS’s SOC 2 is in progress too — on this axis both trail Proton and Virtru today; ASTIS answers with verifiable architecture in the meantime.
Tuta is ahead on post-quantum. Full stop.
TutaCrypt has protected new accounts since March 2024 — CRYSTALS-Kyber + X25519 hybrid, in production, first in the category. If PQ encryption today is your deciding criterion for a self-contained ecosystem, Tuta is currently the strongest choice in this comparison set.
ASTIS Mail uses classical Cv25519 today. Harvest-now-decrypt-later is a real consideration for decade-sensitive data; treat any vendor’s PQ statements as roadmap until shipped.
Pricing
ASTIS Mail
- Solo $179/year · Team $15/seat/mo · Organization $20/seat/mo
- Self-serve, 30-day trial, no services engagement
- 25-seat firm: ≈ $4,500–6,000/year
Two honest shortlists
Pick Tuta if
- Privacy-driven individuals, activists, small teams happy inside Tuta’s own apps
- Post-quantum encryption today as the requirement
- Budget-sensitive buyers — €6/user/month is unbeatable in class
- German jurisdiction with a self-funded, open-source vendor
Pick ASTIS Mail if
- Companies that keep Google Workspace / Microsoft 365 — clients, tooling, IT policy
- Org-level key recovery, audit evidence, white-label under an EU vendor
- Tuta-grade envelope coverage without asking counterparties to change providers
- Portable OpenPGP keys instead of an ecosystem-locked protocol
FAQ
Do both encrypt subject lines?
Yes — both Tuta and ASTIS Mail encrypt subjects; Proton Mail does not (end-to-end). That single row eliminates a lot of products when the requirement is real confidentiality.
Does Tuta work with Outlook or Apple Mail?
No. Tuta has no IMAP/POP3/SMTP by design and no Bridge equivalent; you use Tuta’s apps. ASTIS Mail is also its own client (PWA), but your underlying Gmail/M365 mailbox and clients keep working for everything else.
Which is post-quantum?
Tuta — TutaCrypt, in production since 2024. ASTIS Mail currently uses classical Cv25519; treat any vendor’s PQ statements as roadmap until shipped.
Can a company recover a former employee’s encrypted mail?
ASTIS Mail organization tiers: yes — recovery via the org key in CVS, with custody as an explicit choice: ASTIS Managed CVS, or self-hosted HYOK CVS where ASTIS never touches key material. Tuta: account-level recovery codes; check current admin capabilities against your offboarding requirements.
Sources — retrieved July 2026
- Tuta: what is encrypted
- TutaCrypt post-quantum announcement
- Tuta business pricing
- Tuta on PGP’s gaps (why they left it)
- Tuta security overview
- ASTIS security whitepaper
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Don’t trust either vendor — verify.
Read the security documentation, then run the 30-day trial on your existing Gmail or Microsoft 365 mailbox. Keep the provider. Protect the content.