While I appreciate the condescencion, their website says "We use OpenPGP" and doesn't specify how you can decrypt a message using their webmail client without s

While I appreciate the condescencion, their website says "We use OpenPGP" and doesn't specify how you can decrypt a message using their webmail client without storing (or sending) your keys on their server. If there is a workable solution to that, I'm genuinely curious about it. I'm sure they're a lovely email provider, but when they emphasize 'Secure Email' the onus is on them to prove that their secure system isn't a series of wishes and 'trust us'.