An overview of Canary Mail’s encryption modes:
Canary offers two methods for end-to-end PGP encryption: Automatic Mode and Manual Mode. Automatic mode is recommended for those who are new to e-mail encryption, and who will be exchanging messages only with other Canary users. Manual Mode is more suitable for those experienced with encryption key management and who must exchange both encrypted and clear-text messages.
Note that encrypted messages will not be human-readable when accessed outside Canary, such as through a Web interface.
With Automatic mode, you don’t have to worry about managing encryption keys. Encryption is handled by Canary behind the scenes, but anyone you exchange messages with must also use Canary so messages can be automatically encrypted and decrypted.
When composing an encrypted message, if the following conditions are met, you will notice a blue padlock and the Encryption Enabled status message, illustrated below.
While composing a message, click the padlock to disable encryption for that message. (You can also disable encryption entirely in Canary Settings, under Encryption.)
When using manual encryption mode, it’s necessary to import your existing encryption keys.
To do so, use either iTunes File Sharing or browse iCloud Drive for your keys.
This is how the Auto and Manual Encryption Modes work on Canary Mail. Use the one that fits you the best.