Fiona from Jumble here - happy to answer any questions you may have.
A little bit of background to Jumble....it's free and it integrates with your Gmail account. The integration is important for two reasons: to give you a seamless experience and to retain its zero knowledge provider status – Jumble has no access to the underlying emails and likewise the email provider has no access to the keys so once the emails are encrypted they can only ever be decrypted and read by the sender and recipient #PrivacyMatters
Jumble