Show HN: Private Forms: PGP-Encrypted Webforms for Privacy-Conscious Receipients

by sjs382 • 11 years ago

60 41 11 years ago

sjs38216• 11 years ago

Hi, HN! Founder here (on my 2nd "startup").

I strongly believe in the need for private communication, especially in the context of doctors-patients, clients-lawyers or sources-journalists.

PGP has done a great job of allowing private communication between two parties, but it places a heavy burden on both the sender and the recipient. Often though, the person who needs to send the private communication is less tech-savvy than the recipient. Private Forms removes the burden from the sender, and places it squarely on the recipient.

With Private Forms (https://privateforms.com) you can create an embeddable web form (with custom fields) that encrypts messages client-side, before being sent to the server (and emailed to the recipient). These messages are encrypted using the recipient's PGP public key, which can only be decrypted using their private key—this way, not even we can view the form submissions. We can help less technical users by generating a keypair for them (again, client-side), or they can upload their own public keys.

Recipients can view form submissions on the web (using their private key, which is never transmitted to our server), or via their own email client that supports PGP decryption.

This is very much a MVP, with regards to the interface and the number of features, but I wanted to get this out in front of as many people as possible!

Also, if you're a ProductHunt user, I'd appreciate some upvotes! http://www.producthunt.com/tech/private-forms

pipework• 11 years ago

Are you using any open source projects? I'm deeply curious about how you're doing the encryption and am usually skeptical of in-browser cryptography, though I'd love to be able to trust some of the crypto libraries that have been transpiled to JavaScript.

sjs38216• 11 years ago

I am. I'm making heavy usage of keybase.io's kbpgp: https://keybase.io/kbpgp

nickpsecurity2• 11 years ago

You have an interesting product. I like the simplicity of it both in terms of ease-of-use and ability to make it more secure later. Are you intending to keep this thing going or build it up for an acquisition? If the former, I might do a consult with you on bulletproofing it in the future once its grown enough to justify the cost. If you like that, just keep the implementation well-documented, modular, and basically easy to reimplement if necessary.

sjs38216• 11 years ago

I didn't build this looking to be acquired, but it would be silly not to be open minded at this early stage.

Basically, I plan to continue working on this, while supplementing myself with my regular day job, until an alternative makes sense.

MichaelGG6• 11 years ago

How do users verify keys are correct and not being sent to your server?

sjs38216• 11 years ago

This is important! Thanks for asking!

For non-technical users, we offer the ability to generate a key pair for you. But for more advanced (or more privacy-conscious) users, we offer the ability to upload your public key (which is used to encrypt the form data).

As far as decryption goes, form data is stored in our backend and you can decrypt it via the web app if you trust that we don't upload your private keys. We don't upload them—they're all stored in your browser's localstorage—but if you want to use the web app, you still have to trust us (if you're unable to verify that we don't upload them).

The nice thing though, is that you don't need to use our web app to decrypt the messages—you can use any PGP-enabled email app, or the command line. We send all encrypted forms to you, via email, so you can choose how to decrypt them using your private keys.

So, you can use PrivateForms in a way that you don't need to trust us at all. It's all "host-proof" in the way described here: https://www.passpack.com/blog/2008/03/host-proof-hosting/

bramblerose• 11 years ago

this way, not even we can view the form submissions

That's not true. PF cannot view the submission /after it has been submitted, assuming your javascript does what you say it does/. Which means it protects people from someone knocking on your door asking for old data, but not from the FBI knocking on your door and asking to tap future submissions.

This is probably a reasonable tradeoff, but you have to be honest in this in your communication. "That is because your user's submissions are encrypted using your key (which we don't have) before being sent to our servers." is true, but it suggests this would always be the case -- also in the future -- and you simply cannot guarantee that.

sjs38216• 11 years ago

That's an interesting (and accurate) point. An interested user could verify the source of the embedded page, and ensure that it doesn't change.

This also doesn't protect the sender from a keylogger installed on their machine. Private Forms is just one additional layer of security.

I also intend to add a warrant canary, but I felt like that wasn't needed pre-launch. This is definitely a high-priority item though, now that I have launched.

tortilla• 11 years ago

Any screenshots?

sjs38216• 11 years ago

There's an example form that I just threw up right here: http://sjstrutt.com/contact/

I know the marketing and home page need a lot of love, but I wanted to get this out in its present state. :)

davidcollantes2• 11 years ago

Submit with empty fields renders a 404 on the example.

sjs38216• 11 years ago

Oh, and I have it redirecting to a "thank you" page on complete that doesn;t really exist, so you will get a 404. The "thank you" page is configurable.

daveloyall• 11 years ago

Looks like it uses this internally: https://github.com/keybase/kbpgp

Also, what's this? https://github.com/keybase/kbpgp/blob/master/LICENSE

sjs38216• 11 years ago

Yes, we make heavy usage of Keybase's KBPGP. It's a great project and we're very thankful that they released this under an open license.

We had a copyright attribution page that was totally buried (sorry!), but I just added it to the footer and FAQ.

locacorten4• 11 years ago

The FAQ describes how the data center is using super-sophisticated security. Why is this necessary if the data is encrypted at the client? (perhaps I'm missing something about the threat model).

sjs38216• 11 years ago

It isn't important, but it's still a detail that some people who are security-conscious might care about.

locacorten4• 11 years ago

I'm sorry but I beg to differ. Encryption is a very powerful tool -- the whole point of doing encryption at the client is that we don't care about data center security any more. As long as the data isn't lost, my data remains confidential. NSA, KGB, the Chinese hackers can't read my data. Period.

If you start telling me that I'm paying for security measures that have no effect on your service security guarantees, I think you're selling snake-oil.

At this point, I'm very reluctant to trust my data to your service.

bwblabs2• 11 years ago

I cannot try anything before entering my CC number (and paying, no free month or anything), nor finding any detailed information about the setup (apart from 'public/private key client side JS'). But the site/server/data center security probably does matter if the JS is hosted at their site / servers.

Edit: See link below: https://privateforms.net/embed/rNKlzL

So you get jquery, moment, bootstrap + datatimepicker, kbpgp and a few lines of glue to use kbpgp to send and XMLHttpRequest, basically:

    kbpgp.KeyManager.import_from_armored_pgp({
        armored: '-----BEGIN PGP PUBLIC KEY BLOCK-----\n' +
                 /* key */
                 '-----END PGP PUBLIC KEY BLOCK-----'},
        function(err, keyManager) {
            kbpgp.box({msg: '**form=data**', encrypt_for: keyManager},
            function(err, encryptedString, encryptedBuffer) {
                //send result;
            }
        );
    });

locacorten4• 11 years ago

I like your answer because you're describing a new threat model: an adversary tries to subvert the encryption process. Their service does not protect against such a threat.

Securing the data center is the least of your worries for such an attacker. I'd detail additional attacks that all subvert the encryption process:

1. Compromise the site's private SSL certificate. This allows the possibility of MITM attacks. There is some evidence that NSA is already mounting such attacks on the Internet.

2. Malware on the client-side. A compromised browser, or a compromised OS.

3. The US government mandating that NSA installs hidden firmware on all data center servers.

I argue that strong semantics are extremely important when building secure services. I thought their service offers one such semantic: client-side form data encryption. They do not offer JS code integrity or any guarantees about the client-side encryption not being subverted.

By telling people about datacenter security and then calling it a "a detail that some people who are security-conscious might care about" or "data center security probably does matter", you continue to raise the fog of confusion in people's minds. Instead, the FAQ could educate the users and separate client-side encryption (which is what the service offers) from client-side code integrity (which the service does not offer).

sjs38216• 11 years ago

I've implemented a 14 day trial period, for users to test the service before staying with us.

sigjuice• 11 years ago

Nitpick: https://privateforms.com/faq should say "All you need is internet access and a browser that supports JavaScript!" (No space between Java and Script)

sjs38216• 11 years ago

Fixed! Thanks for the good eyes :)

philip1209• 11 years ago

I wonder if Keybase could start to provide apis/web packages for something like this.

bgibson• 11 years ago

Cool. A few thoughts:

1. On the front page "Only you have the encryption key" could be confusing to folks new to PGP, consider instead "Only you have the decryption key". Then elaborate below - your encryption key/pubkey is uploaded to your service and made available to any users of your form, while your encryption/privkey remains secret.

2. What's your experience doing crypto in browser Javascript? I looked at that earlier this year but it was still pretty immature. Things like Mailvelope are a good start but not 100% reliable.

sjs38216• 11 years ago

Thanks for point #1. I'm going to change that right away!

I use mailvelope for reading Private Forms submissions in Gmail, and it's wonderful.

As far as crypto in the browser, kbpgp is a great tool, assuming your browser supports it.

sjs38216• 11 years ago

In response to user feedback, I've implemented a 14-day trial period for all subscription plans.

aytekin• 11 years ago

Another example to how good ideas come out at the same time!

We have just recently released the exact same feature. Not all JotForm users use it but the users who use this feature are really excited about it. http://www.jotform.com/encrypted-forms/

It is free upto 100 responses/month.

Show HN: Private Forms: PGP-Encrypted Webforms for Privacy-Conscious Receipients

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