The C-layer is our blockchain. For c.Email, it’s where we publish your public encryption key and public verification key. These are public so that you don’t need to exchange them with all your chosen recipients before sending them an email (your decryption key, on the other hand, will always be private and stored only on your device). They are published anonymously – and because they are published on-chain, they cannot be tampered with.
Your private decryption key is stored on your device only, so only you can decrypt the emails you receive.