c.Email protects your emails with end-to-end encryption, a highly secure communication process that ensures only the sender and recipient of an email can read it.
Emails are encrypted on the sender’s device before sending, remain encrypted in transit, and are only decrypted on the recipient’s device. Nothing is ever stored, encrypted, or decrypted on our servers. This means no-one else can read your emails: not your email provider, and not us, even if we wanted to.
The c.Email encryption protocol is a hybrid protocol combining both classical and post-quantum secure algorithms — specifically an implementation of the Kyber algorithm for post-quantum security, as officially standardised and recommended by NIST (the National Institute of Standards and Technology).
A hybrid approach combines the benefits of post-quantum security — resistance to attacks even from hypothetically powerful computers in the future — without sacrificing the strength of existing algorithms if an undiscovered flaw in post-quantum systems is discovered future. This is the approach recommended by the majority of cybersecurity bodies and organisations.
We encrypt your emails’ body and attachments, but not their recipient addresses or subject lines. This is to ensure you can search your entire email archive, rather than only emails stored locally.