Hi - crypto team lead here. I'll hijack this comment to try to explain what Proton Bridge is intended to do, and why it doesn't work the way OP wants.
Bridge is a proxy which hosts a local IMAP and SMTP server, and takes "normal" unencrypted and unsigned messages from desktop MUAs like Thunderbird, signs and encrypts them, and then sends them out. Note that this requires changing the MIME message somehow.
OP writes:
> Everything was great until I decided the other day that I’d also like to do PGP signing on my outgoing messages.
The "intended" way to do this is enable the setting in Proton Mail that says "Sign external messages" :) That way, Bridge will sign them for you. (Internal messages are always signed.)
> Tough luck, bucko, we’re the SECURE email company, you’ll upload your private key to our servers and you’ll like it!
FWIW, private keys are stored encrypted on the server, we don't have access to them.
But yes, the entire goal of Proton is to handle PGP for you, without having to set up PGP encryption and signing manually on all of your devices. I know that the HN audience is fully capable of doing so, but our goal is to make it easier for everyone else :)
> It’s absurd that there’s no way to disable this, no option to tell Proton “if you see a multipart/signed or multipart/encrypted message, just leave it the hell alone.”
IMO, if we see a multipart/signed message, we should still encrypt it whenever possible, not leave it alone. But note that normally in OpenPGP, signing and encrypting is a single operation. It's possible in PGP/MIME to sign a message first and then encrypt it, but we don't support sending that way at the moment, though we could of course add that in the future. But in any case, that's the reason we currently recommend signing using Bridge rather than manually using gpg or similar.
> FWIW, private keys are stored encrypted on the server, we don't have access to them.
I'm always bothered by statements like this because it appears to be skimming over if the provider can perform cryptography with the key. My understanding is that those keys are only decrypted in the users apps/web browser, not server-side. Is that right?
You need to trust that the provider doesn't perform additional operations along side legitimate user triggered actions, which I believe PM handles.
> > Tough luck, bucko, we’re the SECURE email company, you’ll upload your private key to our servers and you’ll like it!
> FWIW, private keys are stored encrypted on the server, we don't have access to them.
This is frankly fucking ridiculous. Users (including me) have been requesting a change to this for years. It's thanks to this bullshit that ProtonMail's key feature for me is just 'isn't Google'.
Why can't you just detect that it was already signed with a valid signature, especially if you have the user's public key?
PS: the lack of threading support in your mobile apps is embarrassing, it's been like this for years. No I will never use your web client. Stop trying.
It was good enough for Snowden. Apparently not good enough for the people here who want a centralized server that requires phone numbers run by a hip guy with a cute name.
twiss|2 years ago
Bridge is a proxy which hosts a local IMAP and SMTP server, and takes "normal" unencrypted and unsigned messages from desktop MUAs like Thunderbird, signs and encrypts them, and then sends them out. Note that this requires changing the MIME message somehow.
OP writes:
> Everything was great until I decided the other day that I’d also like to do PGP signing on my outgoing messages.
The "intended" way to do this is enable the setting in Proton Mail that says "Sign external messages" :) That way, Bridge will sign them for you. (Internal messages are always signed.)
> Tough luck, bucko, we’re the SECURE email company, you’ll upload your private key to our servers and you’ll like it!
FWIW, private keys are stored encrypted on the server, we don't have access to them.
But yes, the entire goal of Proton is to handle PGP for you, without having to set up PGP encryption and signing manually on all of your devices. I know that the HN audience is fully capable of doing so, but our goal is to make it easier for everyone else :)
> It’s absurd that there’s no way to disable this, no option to tell Proton “if you see a multipart/signed or multipart/encrypted message, just leave it the hell alone.”
IMO, if we see a multipart/signed message, we should still encrypt it whenever possible, not leave it alone. But note that normally in OpenPGP, signing and encrypting is a single operation. It's possible in PGP/MIME to sign a message first and then encrypt it, but we don't support sending that way at the moment, though we could of course add that in the future. But in any case, that's the reason we currently recommend signing using Bridge rather than manually using gpg or similar.
8organicbits|2 years ago
I'm always bothered by statements like this because it appears to be skimming over if the provider can perform cryptography with the key. My understanding is that those keys are only decrypted in the users apps/web browser, not server-side. Is that right?
You need to trust that the provider doesn't perform additional operations along side legitimate user triggered actions, which I believe PM handles.
https://proton.me/blog/encrypted-email
pxc|2 years ago
> FWIW, private keys are stored encrypted on the server, we don't have access to them.
This is frankly fucking ridiculous. Users (including me) have been requesting a change to this for years. It's thanks to this bullshit that ProtonMail's key feature for me is just 'isn't Google'.
blitzar|2 years ago
unconed|2 years ago
PS: the lack of threading support in your mobile apps is embarrassing, it's been like this for years. No I will never use your web client. Stop trying.
bigfishrunning|2 years ago
brookst|2 years ago
It’s a user benefit. By definition that means it’s a marketing term. That is not mutually exclusive with being a general concept.
pavs|2 years ago
nabla9|2 years ago
You can genuinely support privacy and still have features or user cases that don't work. This feature does nothing to weaken privacy.
twleo|2 years ago
But for PGP? You should treat it seriously, considering your target customers.
nvy|2 years ago
thesf|2 years ago
hardenedproof|2 years ago