c.Email

c.Email is an email-security app and browser extension for people who want to protect messages sent from Gmail or Outlook without changing addresses. Its free tier includes encryption and verified sending, but setup requires an identity check and its strongest mode requires ongoing recipient verification.

Overview

c.Email connects to an existing Gmail or Outlook address, so users can keep their current mailbox rather than open a new account. Three security levels—Not secure, Secure and For Your Eyes Only—let senders choose how much protection a message needs. Verified sending uses identity verification and cryptographic proofs to authenticate the sender.

Setup involves a one-time identity check using an existing ID and a liveness check. Identity data stays on the user's device. That keeps the identity data off c.Email's servers, though the check is a substantial extra step for people who want a simple email add-on.

Key features

Encryption on users' devices

Messages are encrypted on the sender's device and decrypted on the recipient's device; c.Email servers do not store, encrypt or decrypt them, with a business-use exception. The hybrid encryption combines classical cryptography with ML-KEM, the post-quantum standard published by NIST. The device-based handling is a strong fit for users who want message contents kept away from the provider, but business customers should account for the stated exception.

For Your Eyes Only

This setting requires continuous liveness verification from the intended recipient. It adds an extra layer of control over who can read a message, but also adds friction at the point of access. It is best reserved for messages where that added check is worth the inconvenience.

Identity and the C-layer

c.Email is built on cDot, a protocol for encrypted identity, email, messaging and payments. Public encryption and verification keys are stored on the C-layer, a distributed blockchain of independent nodes that is under development; anyone can run a node. The protocol's scope is broader than email, but the network remains a developing part of the system.

Pricing

The free plan is unusually complete for individuals: it has no address-count cap and includes the core security features. There is no paid upgrade with a published price to compare yet. Premium may suit individuals seeking advanced features when it arrives; the business tiers target organisations, with Self-Serve offering a choice of hosting and Business Plus aimed at customised protection. Premium features are planned as part of an expanded product suite.

Platforms

c.Email is available as an app and browser extension, including a Chrome extension. It supports Gmail and Outlook addresses, and mobile apps are available. Keeping an existing address makes it less disruptive than switching mailboxes, though use depends on those supported email services.

Who it's for

c.Email suits individuals who want encryption and sender verification on a current Gmail or Outlook address without paying for the core features. It also gives organisations a prospective route to team protection and server-hosted encryption. People who do not want to complete an ID and liveness check, or who need the strongest mode without continuous recipient checks, should look elsewhere.

Pros and cons

• Pros: The free tier includes encryption, verified sending and For Your Eyes Only protection, with unlimited email addresses.
• Pros: Message encryption and decryption happen on sender and recipient devices, and identity data remains on the user's device.
• Cons: Initial setup requires an ID and liveness check, which adds friction before use.
• Cons: For Your Eyes Only requires continuous recipient liveness verification, making it less convenient for routine messages.
• Cons: The business server-handling exception means the device-only model does not apply uniformly to business use.
• Cons: Premium and business plans are coming soon, with custom pricing rather than a published rate.

Alternatives

For a broader starting point, browse Email Encryption Software or File encryption tools.

• FlowCrypt may fit users comparing free extension-based email encryption; its free plan is for fewer than 100 users and has a 5 MB attachment threshold.
• SecureMyEmail is worth considering for people who want support across Windows, macOS, iOS and Android; its free plan covers one email address.
• Lockbin offers a free plan for one user, with a 25 MB attachment limit and six months of inbox storage.
• Mailvelope is another extension and web option for readers comparing email encryption tools.
• DataMotion Secure Email Exchange may suit organisations looking for an enterprise offering with sales-led pricing.
• gpg4o is a Windows option for users seeking OpenPGP encryption with Microsoft Outlook.
• Virtru Email Encryption is a paid alternative with web, desktop and mobile platforms; its Starter plan costs $119 a month, billed annually, for 5 users.
• RMail is another paid email option.

Verdict

Choose c.Email if you want to keep Gmail or Outlook, add sender verification and encryption, and get those core protections without a subscription. Its device-based encryption and unlimited addresses make the free tier compelling; the identity check and continuous liveness requirement are the main reasons to choose a less demanding alternative.