[mike-cardwell]

On Hemlis's front page:

"We have all intentions of opening up the source as much as possible for scrutiny and help! What we really want people to understand however, is that Open Source in itself does not guarantee any privacy or safety. It sure helps with transparency, but technology by itself is not enough."

They have no intention of releasing the source code. Use https://www.surespot.me/ instead, it does the same stuff, already exists, and is released under the GPL (v3).

[em3rgent0rdr]

Surespot depends on a bunch of google play services and is officially distributed on google play. Is there a way to install pre-compiled surespot apk outside of google play for those that don't install proprietary google code on their phone? I noticed that the open-source android apk repository F-Droid can't distribute it for this reason: https://f-droid.org/forums/topic/surespot-encrypted-messagin...

(Side note: moxie prohibits TextSecure on F-Droid as there is no forced auto update like google play. I currently have to download and compile the TextSecure source code myself, which is no biggie, but as a CM user, I'm definitely excited about this integration!)

[perlpimp]

Sounds like a trap to me, not having the source code. Maybe it works for now but investing trust as things are now I'd rather go with opensource client.

Trust must be earned, so far it they brag about way they made tech work with a patched version of android - they don't really put forth anything that will give them credibility as a very secure protocol.

Claims without proof are just that.

[tptacek]

The track record of open source cryptography is bad.

[dublinben]

The track record of closed source cryptography is worse.

[IanChiles]

cough cryptocat cough

[atmosx]

The cryptocat issue can be viewed sideways:

* Open source applications are bad, see what happened to cryptocat?

* Open source is awesome! Look what happened to cryptocat!

If cryptocat was closed-source... would ever be noticed? I wonder...

[tptacek]

People insist on looking at this through their default prism of "closed source bad, open source good". But people with crypto experience have other prisms; for instance, "competent, well-vetted crypto" versus "amateur enthusiast crypto". Sometimes open source is also competent and well-vetted, but vetting is expensive, and there is a lot of amateur crypto out there.

[wglb]

For example?

[eliteraspberrie]

There are claims that Crypto AG products used to leak keys in ciphertext, at the request of the NSA:

http://www.hermetic.ch/crypto/kalliste/speccoll.htm

[tptacek]

I stifled the urge to say the same thing, but then realized that I'd lose the evening to defining what "mainstream" meant, after people dredged up random examples of snake oil from Schneier blog posts; not to mention the inevitable rehashing of the "beware custom algorithms and 390244 bit keys" thread, which is going to have to happen now because bringing up crypto truisms from the late-90s makes people feel smart.

[tga_d]

You're being unfair and you know it. Lavabit, the RSA fiasco, Apple's imessage crypto, etc. are all perfectly mainstream examples of closed-source crypto done wrong. As you said yourself, the only thing that conclusively makes a difference is if the crypto is "well vetted," having the source available is simply a means of making this easier. Classifying the quality of crypto-implementations based on the source model alone ("The track record of open source cryptography is bad.")is just disingenuous.

[uniclaude]

Please explain for those of us who are not good enough in the field (I'm genuinely asking).

I was under the impression that software like GnuPG and OpenSSL could be considered safe, so seeing a security professional warning about a negative track record of open source cryptography is worrisome.

What exactly should we be careful of when it comes to open source cryptography?

[lvh]

Not all open source code is broken; just a lot of it is. I think tptacek is trying to say that open source vs closed source is a mediocre predictor of the quality of a cryptosystem :)

[illicium]

OpenSSL

[tptacek]

You'd be making a pretty big mistake to opt for something that hadn't been vetted, over TextSecure, simply because of the availability of source code.

[mike-cardwell]

Personally, I've used both, but settled on SureSpot for the moment. SureSpot uses data exclusively, which is cheaper than SMS for me. Although I understand that TextSecure now has (or will be getting soon) a data channel. So I'll definitely take another look.

Moxie has proven himself to be more than capable of building such a system, but the author of SureSpot seems more than competent too. See the section titled "Technical Overview" on:

https://www.surespot.me/documents/how_surespot_works.html

Interesting fact: TextSecure wasn't made open source until it was bought by Twitter: https://dev.twitter.com/blog/whispers-are-true - IIRC, prior to this the website claimed it was open source, but offered no way of getting the source, and if you asked for it, you would find out it was only given to trusted third parties to perform security reviews.