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Scramble.io: secure email for everyone

dcposch.github.io

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Re: Scramble.io: secure email for everyone

#101

Post by jaekwon »

tptacek wrote: post #94
jaekwon wrote: post #81

Earlier quoted context omitted.

A secure environment would require a vetted browser and no other hostile extensions. That's certainly possible, so Scramble does have a use.

I see. So, if I set up an intricate browser clean-room environment, and I assume that the Javascript verification system you come up with actually works, I can get some of the benefit of simply installing GPG and using POP mail .

You'd still have to vet your GPG install & mail client code. Also, it's not difficult to fork the code to create a client that doesn't use the browser at all. It just hasn't happened yet.

How do you know which public key belongs to the address? Key servers? Web-of-trust? Look it up on their homepage?

Scramble has an address -> pubkey resolution system which balances security with usability.

At least with Scramble you can create a secure USB stick to boot from with all of that preconfigured. Any solution that uses bare GPG still has severe usability problems.

http://www.gaudior.net/alma/johnny.pdf

Re: Scramble.io: secure email for everyone

#102

Post by DanBC »

What articles have you / your team had published in crypto journals? Where did you / your team study cryptography?

The logo is a Rubik's cube. That's not a great logo for a cryptographic app because Rubik's cubes are trivially solvable.

Re: Scramble.io: secure email for everyone

#103

Post by blahbl4hblahtoo »

jaekwon wrote: post #92
tptacek wrote: post #83

Earlier quoted context omitted.

Usually, when people claim to have refuted our crappy old article on Javascript crypto, they have some misguided but at least potentially falsifiable argument for having accomplished that; for instance, "there are browsers with secure RNGs now". You don't even have that. From what I can tell, you have literally no argument at all; instead, you "agree" with the article while drawing exactly the opposite conclusion tha…

My argument is this: "This is also a PGP application that most people can benefit from immediately (compared to using Hotmail), and one that can be used by even the most targeted users if their environment is set up correctly once the extension is out." Scramble performed encryption on the server, then my argument is false. But the design of Scramble's protocol is such that the security of the application depends onl…

That's the point. If you have to "setup the environment correctly" you should implement a native client. GPG is secure because it transfers data...not code. That's actually the webs biggest problem...you can't trust code given to you by some stranger. If you transfer data you can verify that it hasn't been modified in transit. Its really impossible to verify that code given to you performs the way that you think it will.

Re: Scramble.io: secure email for everyone

#104

Post by jaekwon »

peterwwillis wrote: post #97
jaekwon wrote: post #90

Earlier quoted context omitted.

Yes, we're on the same page! We have an idea for how fake messages would be passed around fake friends, and how to grow this "dark" network organically. Let's collaborate!

I think you're going to be disappointed. The only way this could work is based on network participants, and that's highly subjective. But here's an idea that might be plausible. You have four nodes in your network: B, C, D, E. B wants to send E a message, but doesn't want anyone who might be observing the whole network to know. B sends garbage messages all day at random to all active peers on the network , or as clos…

What do you mean by "The only way this could work is based on network participants, and that's highly subjective." ?

Re: Scramble.io: secure email for everyone

#105

Post by kingzero »

dcposch wrote: post #52
dcposch wrote: post #40

Earlier quoted context omitted.

Yeah, I read your Matasano post, "Javascript crypto considered harmful", and I agree-- Javascript crypto is hard! But it's not impossible. The reason I chose that route is because I want to make it as easy as possible for users to try out and adopt. Just testing it out? No installation required. I think that security is at least equal parts a technical problem and an adoption problem. The status quo is that nearly al…

PS: Most users are not power users, and won't download the extension and manually check signatures. As mentioned in the writeup, there's a beautiful way you can protect even non-power-users. Because the extension downloads and verifies the webapp HTML, CSS and JS every time it runs, the web app is constantly being validated. As long as you have a critical mass of power users who installed the extension, an adversary…

> As mentioned in the writeup, there's a beautiful way you can protect even non-power-users. Because the extension downloads and verifies the webapp HTML, CSS and JS every time it runs, the web app is constantly being validated.

Imagine the following. An Attacker manages to hijack your server. They fingerprint[1] the browsers of each user and only send malicious JS to certain users that dont use your extension. No one will ever know, that they have been compromised.

[1] https://panopticlick.eff.org/browser-uniqueness.pdf

Re: Scramble.io: secure email for everyone

#106

Post by jrochkind1 »

blahbl4hblahtoo wrote: post #95
jrochkind1 wrote: post #34

nice. secure end-to-end encryption with a good browser-based UI is kind of a holy grail. They say it's open source, but I can't find links to the source anywhere. Anyone?

I have to disagree. I'm not sure that is the "holy grail"...i think its not even possible with common browser runtimes.

Yes, I agree; the fact that it's unclear if it's possible is what makes it the holy grail, it's unclear if the holy grail actually exists, but lots of people really want it. :)

Re: Scramble.io: secure email for everyone

#107

Post by tptacek »

orthecreedence wrote: post #100
tptacek wrote: post #46

Earlier quoted context omitted.

It is impossible. The features required to make browser Javascript safe for crypto aren't even on the roadmaps of browser vendors. Your reason for using browser Javascript for crypto --- here, Recurity's JS PGP implementation --- is the same as every other JS crypto project's reason: doing everything in the browser makes it easier for users to adopt your project. You are not the first person to point this out and you…

Perhaps I'm ignorant, but I've read your "JS crypto considered harmful post" and I disagree with the key points. 1. Browsers, at least the ones that matter, provide window.crypto (with a CSPRNG). This makes generating IV's for CBC "safe," makes generating RSA keys "safe," makes generating random keys "safe." Or am I missing something? Assuming the JS crypto code itself is actually sound, the PRNG seems to be the miss…

We are not talking about crypto done in browser extensions. We're talking about a project that knows about extensions, knows how to package their project as an extension, but refuses to do so, because that would cost them users, who generally don't want to install extensions.

Re: Scramble.io: secure email for everyone

#108

Post by jaekwon »

blahbl4hblahtoo wrote: post #53

If you just expose your service as an API then you don't have to worry about users trusting code given to them by the site. Then use a native client app that doesn't suck to interact with the service...all of the encryption is done client side with all of the messages being encrypted end to end. JavaScript encryption just isn't really valid in browsers...the browser runtime is to blame. Its funny that people have to…

That could happen. The API is already there, in JSON over HTTP. One could gut all the UI logic and run it in a node program, or rewrite the client.

Re: Scramble.io: secure email for everyone

#109

Post by blahbl4hblahtoo »

jaekwon wrote: post #101
tptacek wrote: post #94

Earlier quoted context omitted.

I see. So, if I set up an intricate browser clean-room environment, and I assume that the Javascript verification system you come up with actually works, I can get some of the benefit of simply installing GPG and using POP mail .

You'd still have to vet your GPG install & mail client code. Also, it's not difficult to fork the code to create a client that doesn't use the browser at all. It just hasn't happened yet. How do you know which public key belongs to the address? Key servers? Web-of-trust? Look it up on their homepage? Scramble has an address -> pubkey resolution system which balances security with usability. At least with Scramble you…

Verifying the code on your system is something that can be easily done and easily verified the next time you use it. Its your system after all.

I salute what you are trying to do, but you have to understand that the Js browser method, as it stands today, is a dead end.

Re: Scramble.io: secure email for everyone

#110

Post by jaekwon »

mdip wrote: post #67
blahbl4hblahtoo wrote: post #53

If you just expose your service as an API then you don't have to worry about users trusting code given to them by the site. Then use a native client app that doesn't suck to interact with the service...all of the encryption is done client side with all of the messages being encrypted end to end. JavaScript encryption just isn't really valid in browsers...the browser runtime is to blame. Its funny that people have to…

Its [sic] funny that people have to all learn the same lessons over and over again That pretty much defines what the field of computer security is . From DES to AES, we learned the same lesson: As things designed to be secure are put out in the real world, with sufficient enough time, they're broken. It's important not to make the same mistakes again and again, and that's nearly impossible to do with JS-Crypto since…

That's already happened w/ the crypto.getRandomNumber function, which openpgp.js uses/
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