End-to-End Encryption (E2EE) in Millionaire.email: Real Privacy With OpenPGP & S/MIME
- Mithun GS
- Dec 9, 2025
- 3 min read
In 2025, secure email means more than “encrypted servers.” True privacy comes only from End-to-End Encryption (E2EE) — where messages are encrypted before leaving your device, and only the intended recipient can decrypt them.
Millionaire.email is built on this principle. Using OpenPGP and S/MIME, the platform ensures that private keys stay with the user, not the server. This creates real, mathematically enforced privacy that even the provider cannot bypass.
What Is End-to-End Encryption (E2EE)?
End-to-End Encryption protects your messages by encrypting them on your device and allowing decryption only with the recipient’s private key.
This ensures:
Providers cannot read your message
Hackers cannot decrypt stolen emails
Governments cannot demand access to content
Server compromise does not reveal message bodies
Only the sender and recipient hold the power to decrypt.This is true email confidentiality.
How Millionaire.email Implements E2EE
Millionaire.email supports the two strongest global email encryption standards — giving users complete choice and full key ownership.
1. OpenPGP (PGP) – Full User-Controlled E2EE
Millionaire.email provides first-class support for OpenPGP, the open, interoperable encryption standard trusted worldwide.
Key points
ECC keys supported (highly recommended)
RSA keys supported
AES-256 used for message encryption
Private key stays only on the user’s device
Public key uploaded to Millionaire.email for sending encrypted mail
The server never has access to your private key. This is true zero-access encryption.
Workflow
Generate or import PGP keys.
Upload public key only.
Messages are encrypted automatically using the recipient’s key.
Only your device can decrypt them.
This architecture ensures Millionaire.email cannot read any PGP-encrypted messages — even theoretically.
2. S/MIME – Enterprise-Grade Certificate Encryption
For professionals and businesses, Millionaire.email supports CA-issued S/MIME certificates.
Key points
Works with corporate identity systems
Uses certificates signed by trusted Certificate Authorities
Supports ECC and RSA
Private key remains with the user
Perfect for compliance, legal, and enterprise workflows
Millionaire.email acts only as the transport layer — not the key owner. Your certificate, your control.
Why Millionaire.email’s E2EE Is Stronger
✔ Zero-Access Architecture
Private keys never touch the server (PGP or S/MIME). This removes the biggest risk: server-side decryption.
✔ Zero-Trust Philosophy
Millionaire.email does not rely on trusting the server. Encryption happens before the email ever reaches the backend.
✔ Open Standards, No Lock-In
PGP and S/MIME are global standards. You can move your keys to any compatible service or email client.
✔ Works With Any Modern Client
Thunderbird, Apple Mail, Outlook, Android, iOS clients — all supported depending on your encryption type.
Comparison: Millionaire.email vs Proton vs Tuta vs Mailbox.org (E2EE)
Feature | Millionaire.email | Proton Mail | Tuta (Tutanota) | Mailbox.org |
Encryption Standards | OpenPGP + S/MIME | OpenPGP | Proprietary Crypto | OpenPGP + S/MIME |
Where Is the Private Key Stored? | User device only (never uploaded) | Stored client-side, but Proton apps can back up encrypted key to Proton servers | User device (encrypted with proprietary KDF) | User device only (PGP/S/MIME keys) |
Does Provider Ever Receive the Private Key? | No | Encrypted form stored for sync | Encrypted form stored for sync | No |
Can the Provider Access or Recreate Keys? | Not possible (keys never exist server-side) | Theoretically hard, but possible if Proton’s key-backup encryption or password is weak | Theoretically possible if their proprietary system is compromised | Not possible |
Is Server-Side Decryption Theoretically Possible? | ✘ No — keys never leave user control | △ Low risk, but theoretically possible because encrypted key material exists on servers | △ Possible, proprietary encryption means risk depends on implementation | ✘ No — same as Millionaire.email |
Works With Standard Email Clients | ✔ Yes (PGP/S/MIME) | Limited (requires Proton Bridge) | ✘ No | ✔ Yes |
E2EE to External Users | ✔ Standard PGP & S/MIME | ✔ PGP | ✔ Only within Tuta users | ✔ Standard PGP & S/MIME |
Millionaire.email & Mailbox.org → No Theoretical Server-Side Decryption
These platforms follow the strictest model:
Private keys stay exclusively on the user device.
Servers never store them (not even in encrypted form).
Even a full backend compromise exposes zero decryptable data.
This is true zero-access encryption.
Proton Mail → Safer Than Most, but Still Stores Key Material
Proton is strong, but:
They store your private key encrypted so you can sync across devices.
If an attacker breaks the password-based encryption or Proton changes client behavior, theoretically, messages could be decrypted.
This is not a practical risk for most users — but it is a cryptographic fact.
Tuta → Proprietary Encryption, Theoretical Access Risk
Tuta does not use OpenPGP or S/MIME.They encrypt private keys with a password-derived key and store them on the server.
This means:
If their proprietary crypto or password system is ever weakened,
Theoretically, Tuta could decrypt user mail under legal or internal pressure.
Their model is secure, but not as mathematically strict as PGP/S/MIME with true key ownership.
Short Summary for Your Blog
Millionaire.email has zero theoretical ability to decrypt user emails.
Proton & Tuta keep encrypted private keys server-side → theoretically decryptable if encryption is broken.
Mailbox.org behaves closest to Millionaire.email → no server access to keys.
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