ProtonMail Bridge is now open source | Hacker News Reader

ProtonMail Bridge is now open source

protonmail.com

228 pointsBafS25 comments

“ ProtonMail Bridge is a desktop application that allows you to fully integrate your ProtonMail account with any IMAP and SMTP email client, including Outlook, Thunderbird, or Apple Mail. Open sourcing the code lets anyone verify how the encryption process takes place through Bridge as the emails are transferred between your ProtonMail account and your desktop email app.”

For anyone else wondering what this is, looks like it downloads encrypted mail from ProtonMail, decrypts it and exposes the unencrypted mail to your email clients as an IMAP server.

And to think I was going to cancel my subscription because the bridge wasn't open source...

Not to mention that I missed the Linux support announcement: https://protonmail.com/blog/proton-bridge-linux-launch/

Great! I was using another open source bridge but it didn't support 2FA :/

This is really cool to see.

Hopefully I can debug why the Bridge pegs two cores and writes out 10gb+ of a single log line over and over when I try to transfer one particular email through it overnight. :-)

(same thing happens in the dedicated mailbox migration program, which is probably using the same shared libraries)

I emailed them a while ago, to encourage pursuing an open standard for their protocol, such as through the IETF.

Open sourcing Bridge is helpful, and perhaps a step towards that.

Perhaps, with this reference, some other mail providers will implement the server-side protocol to Bridge, and some MUA developers will implement/integrate the client-side protocol.

It would be great if someone forked this to allow it to function as an XOAUTH2 IMAP proxy for other providers.

This would be particularly useful with big e-mail providers (Google, Microsoft) looking at retiring password based authentication in the near future.

It would be great if you opened a pull request to allow it to function as an XOAUTH2 IMAP proxy for other providers.

I've been curious about ProtonMail for a long while - my greatest hesitation is that I use multiple addresses and ProtonMail seems to be based around a single address. I'm not sure why email providers all want to charge per address - why not allow multiple addresses and charge for transit or storage? However at minimum multiple instances of this running could be a step towards multiple accounts.

They allow multiple addresses and domains if you pay for premium, its not per address but a monthly fee which includes the functionality of handling them. Their UI is actually really friendly for multiple addresses unlike for example gmail.

Why per address, you ask? My opinion on why is because it is a finite namespace, so if any single person took a disproportionate amount of names it would adversely impact others. You can approach that by assigning a cost to addresses and adjusting as necessary and/or using quotas to limit abuse/over use of the namespace. In addition, an email provider’s reputation hinges on its ability to prevent abuse on its own platform; the ability to acquire huge numbers of addresses or rapidly switch between addresses would effectively make the provider a safe haven for spammers who are difficult to block externally without blocking the whole provider.

This is mostly conjecture, though; I don’t actually know for sure how it’s viewed by providers and I also don’t have a complete view of how SPAM prevention actually works (certainly seems complicated.)

While they do charge per address for the smallest account size, the Premium subscription includes a few for free and it's very cheap to add additional domains.

I use 6 domains with them; a few from the Premium tier and a few I added as extras. I also get my VPN through Proton and the whole thing costs less than 15USD per month.

As already mentioned in this thread, the interface to handle all this is fantastic too.

The new book “The Infinte Game” has an idea of ‘Just Causes’, an idea that means business, organizations, or individuals have a long term and often not totally achievable goal, that is to benefit customers and society.

I think that ProtonMail has the Just Cause of protecting privacy.

Or they found a good market fit with privacy conscious customers and are going all the way. Either way, it's a win for the consumer.

Nice to see!

I'm on Gnome Linux and ProtonMail only mention Thunderbird in their docs, but I've made the bridge work with Geary too. Geary is a bit more simple and modern looking email client alternative. See https://wiki.gnome.org/Apps/Geary

Still I normally end up using the web interface for ProtonMail as it fits my workflow better and only need to have one tab open in my browser. They even have a nicer looking beta which also has an in-built dark theme at https://beta.protonmail.com

> Still I normally end up using the web interface for ProtonMail as it fits my workflow better and only need to have one tab open in my browser. They even have a nicer looking beta which also has an in-built dark theme at https://beta.protonmail.com

Btw, you can have both static beta web client and offline access to the email messages using https://github.com/vladimiry/ElectronMail even being on free account as opposed to Bridge thing. The app also supports "persistent sessions" feature, unlimited full-text search (body content also gets scnned) and other fancy stuff.

Thanks for the recommendation re: Geary! I've been wanting to trial desktop email clients for awhile now and Thunderbird just doesn't have the polish I've come to expect.

Gmail, et al., have become so bloated in recent years.

Dang. That is encouraging that they can peruse an open source model.

It looks like you still have to have a paid account to use this?

I believe it is one of the premium features, yes.

For those without premium accounts, I have good experiences with https://github.com/emersion/hydroxide

I applause ProtonMail services and initiatives, it can only be good for us.

However why did they develop anything specific? SMTP / IMAP already support secure connection (i believe). Or it could be encapsulated in a secure lower transport protocol.

Also I thought there were tons of GPG/PGP extensions for email clients already to read encrypted emails

IMAP, et al, require mail to be unencrypted on the server side; they are only encrypted in-transit.

Which is why Protonmail uses GPG/PGP for the encrypted ones, I believe. So there should be no reason that we cannot use any mail client with GPG/PGP support.

Their service does stuff beyond the basic functions of PGP. That is handled by the bridge, and wouldn't be handled by your favorite flavor of email client and PGP plugin.

One example: if you message another ProtonMail user, all of the PGP functionality is handled automatically. I don't think this would be possible with any other solution.

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