Product Overview

I. Product Overview

ZTmail: S/MIME encryption for everybody, automated. AI, your key.

The world's first email client with automated S/MIME certificate management + AI assistant. Engineered in Shenzhen, China.

Based on S/MIME international standards and China SM2 standards, it supports RSA, SM2, PQC algorithms for seamless encrypted interoperability with all major email clients. Automated email certificate application and configuration enable zero-threshold end-to-end encryption. It allows flexible integration with any AI model.

II. Core Features

  • Automatic Encryption: Every email is end-to-end encrypted by default, using RSA or SM2 algorithms to guarantee confidentiality throughout the email lifecycle.
  • Digital Signatures: Every email is digitally signed by default to prove sender identity trustworthiness and protect content integrity.
  • AI Assistant: Choose your AI model, bring your own API key, and control your AI assistant. Let AI assist with drafting, polishing, translating, summarizing, and calendar extraction.
  • Identity Choice & Display: Choose which identity to send emails, and clearly view sender identity levels (T1 / T2 / T3 / T4) on incoming mail. Higher levels represent higher trustworthiness.
  • Multi-Account Management: Supports centralized management of multiple email accounts with unified automated encryption.
  • Cross-Platform Support: Supports Windows, macOS, and Linux, with iOS and Android versions coming soon.

III. Product Editions

ZTmail provides two main product editions to meet diverse user requirements:

Edition
Core Value
Identity Display
Free Edition
Experience Automatic Encryption
T1 (Mailbox Validated)
AutoCert Marketplace
Global Interoperability + Identity Display
T1 / T2 / T3 / T4

💡 For detailed pricing, please visit Editions & Pricing →

IV. AutoCert Marketplace

ZTmail carefully selected multiple international CAs to join the AutoCert Market, so users can choose to purchase globally trusted S/MIME certificates (MV/IV/OV/SV) from any CA based on their needs, and all certificates trusted by all email clients.

Product Name
Identity Level
Included Features
Mailbox Edition
T1 (Mailbox Validated)
Publicly trusted S/MIME MV Certificate
Individual Edition
T2 (Individual Validated)
Publicly trusted S/MIME IV Certificate
Organization Edition
T3 (Organization Validated)
Publicly trusted S/MIME OV Certificate
Sponsor Edition
T4 (Sponsor Validated)
Publicly trusted S/MIME SV Certificate

💡 For detailed pricing, please visit Editions & Pricing →

V. Technical Architecture

Built on an integrated client-cloud zero trust architecture, adhering to minimal cloud dependency for ZTmail clients:

  • Keys are generated locally on the client; CSRs are submitted automatically for certificate application and issuance, and private keys never leave the device.
  • Upon receiving a certificate signing request, ZoTrus Cloud CA System sends a verification code to the user's email address. ZTmail recognizes this special email and reply to for email control validation according to RFC8823 for RSA certificates, and according to China ACME standard for SM2 certificates. ZTmail automatically retrieves and deploys these certificates.
  • Users' sensitive data including private keys, contacts, and calendar items are encrypted using a user-configured password, manually backed up to their own mailbox, and manually synced to ZTmail on other devices.
ZTmail

VI. System Requirements

  • Windows: Windows 10/11 and above
  • Linux: Ubuntu 20.04 / Fedora 34 / Debian 11 / Kylin V2403 and above
  • macOS: macOS 11 (Big Sur) and above (Intel / Apple Silicon) (Coming Soon)
  • iOS and Android versions coming soon