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Tox: secure messaging for everyone

tox.im

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Re: Tox: secure messaging for everyone

#41

Post by anologwintermut »

irungentoo wrote: post #32
anologwintermut wrote: post #23

So this appears to naively use DJB's NACL/crypto_box construction, which is a curious choice given the existence of OTR for messaging protocols which would handle things like session key negotiation and provide deniability. First, If I'm reading the source correctly, they are doing public key encryption for every message. Which, ok, DJB was a fan of at least for DNSCurve, but is generally regarded somewhat dimly for…

> Nonce's are "Numbers used ONCE", they 1) don't need to be secret and 2) ARE NOT encryption keys. We know. Putting the nonces in the handshake along with the session public key was simple. In the NaCl docs it is advised that if you can keep the nonces secret that you do so.

Out of curiosity, why not use OTR for messaging?

Re: Tox: secure messaging for everyone

#42

Post by NotUncivil »

unknownian wrote: post #38
kostyakow wrote: post #34

Earlier quoted context omitted.

>Github maintained by someone with a troll username? >Comments like this >> IMPORTANT: release two major sanctioned UIs, one for autists, one with inbuilt support for the previous list so that plebs can't get confused with setting it up and autists don't complain about it getting in their way. de geso > I would suggest a "Advanced options" where the autists can rejoice with all kinds of options (and it doesn't fright…

And another thing: /g/ in particular is known for much pointless banter arguing over the best GNU+Linux distro or giving minor tech support to non-natives of /g/. Attempts have been made before to make something substantial on the board and this time it seems we can do it.

The list of (supposedly substantial) things /g/ has made as compiled by /g/, today [1], is as follows:

1. http://aloonix.neocities.org/

2. https://github.com/notuncivil/host-as-image [2]

3. https://github.com/KittyKatt/screenFetch

4. https://4chan-x.just-believe.in/

5. http://tox.im/

6. http://biebian.sourceforge.net/

The above list is in no particular order.

[1] https://rbt.asia/g/thread/S35615929#p35616305

[2] Full disclosure: this code is mine and I am the one who proposed it for that list. I also submitted a Show HN for it.

Re: Tox: secure messaging for everyone

#44

Post by shin_lao »

tptacek wrote: post #37
shin_lao wrote: post #31

Earlier quoted context omitted.

Your answer raises my eyebrows even more. I ask why you don't use DH and you answer "because we want forward secrecy". DH has been designed for perfect forward secrecy. Therefore I fear we might have some sort of misunderstanding here. You don't want to permit known plain text attack as "in depth defense" approach. If there is ever any weakness in your software, you want to make it very hard to exploit it. Known plai…

DH wasn't designed for forward secrecy.

True, my usage of designed was a little bit liberal here. Mr. Diffie is one of the authors of the first paper to introduce the concept of PFS, but the DH key exchange algorithm hasn't been designed for PFS but rather for 0-knowledge key exchange.

Nevertheless, I stand by my remark regarding the pertinence of DH in that case.

Re: Tox: secure messaging for everyone

#45

Post by peterwwillis »

irungentoo wrote: post #20
shin_lao wrote: post #15

Unconvinced. * Lossless UDP? Is there a reason not to do TCP? * There is no way to know if the public key is genuine, so the system is very sensitive to MITM. * The key exchange is inadequate. Why not do DH if it's just to have session keys? * The system is very easy to brute force as the acknowledgement is based on a known plain text. This is very bad . A quick glance at https://github.com/irungentoo/ProjectTox-Core…

>Lossless UDP? Is there a reason not to do TCP? Hole punching. >There is no way to know if the public key is genuine, so the system is very sensitive to MITM. If you want to add someone you need their public key (their id) which is 32bytes (It's small because we use ECC instead of RSA). Unless someone somehow replaces the key (your id) when you give it to your friend the system should be secure. >The key exchange is…

tl;dr There is a buffer overflow in read_packet(). See below.

edit Shit, i'm wrong. I missed this line 599 of Lossless_UDP.c:

    if (size > MAX_DATA_SIZE)
        return 1;
That is the only section that verifies the size of the memory being copied, which is still dangerous. Every memcpy should enforce the size being no greater than the size of Data.data, and not rely on .size having been previously set properly.

Re: Tox: secure messaging for everyone

#46

Post by [deleted] »

NotUncivil wrote: post #42
unknownian wrote: post #38

Earlier quoted context omitted.

And another thing: /g/ in particular is known for much pointless banter arguing over the best GNU+Linux distro or giving minor tech support to non-natives of /g/. Attempts have been made before to make something substantial on the board and this time it seems we can do it.

The list of (supposedly substantial) things /g/ has made as compiled by /g/, today [1], is as follows: 1. http://aloonix.neocities.org/ 2. https://github.com/notuncivil/host-as-image [2] 3. https://github.com/KittyKatt/screenFetch 4. https://4chan-x.just-believe.in/ 5. http://tox.im/ 6. http://biebian.sourceforge.net/ The above list is in no particular order. [1] https://rbt.asia/g/thread/S35615929#p35616305 [2] Full…

[deleted]

Re: Tox: secure messaging for everyone

#47

Post by latitude »

Oh, I see you helped yourselves to my Secure Chat logo -

http://dribbble.com/shots/479881-Secure-Chat

http://logopond.com/gallery/detail/165288

https://www.google.ca/search?q=secure+chat+logo - first page hit too

Not cool at all, "cool guys around the world".

--

(edit) Regardless of whether this was copied, over-inspired or independently conceived (but let's be realistic here), the generally accepted rule of the game is that the first to the finish line gets to keep the logo. I don't make my living with logo design, but I did kill a week of sketching, refining and re-balancing on this one and I do happen to like it a lot. For what it's worth, I wrote a P2P VPN system in the past (called Hamachi) and I am involved in p2p and crypto domains in general. So I expect you to extend some professional courtesy, change the logo and close this matter in an amicable matter.

Re: Tox: secure messaging for everyone

#48

Post by znq »

anologwintermut wrote: post #41
irungentoo wrote: post #32

Earlier quoted context omitted.

> Nonce's are "Numbers used ONCE", they 1) don't need to be secret and 2) ARE NOT encryption keys. We know. Putting the nonces in the handshake along with the session public key was simple. In the NaCl docs it is advised that if you can keep the nonces secret that you do so.

Out of curiosity, why not use OTR for messaging?

Probably because OTR only works when both parties are online at the same time.

Edit: that said I haven't looked at their solution. Maybe it has the same issues. Or worse.

Re: Tox: secure messaging for everyone

#49

Post by sehrope »

latitude wrote: post #47

Oh, I see you helped yourselves to my Secure Chat logo - http://dribbble.com/shots/479881-Secure-Chat http://logopond.com/gallery/detail/165288 https://www.google.ca/search?q=secure+chat+logo - first page hit too Not cool at all, "cool guys around the world". -- (edit) Regardless of whether this was copied, over-inspired or independently conceived (but let's be realistic here), the generally accepted rule of the game…

Very nice logo by the way. Took a second glance to see the speech bubble at the top but once you do it's beautiful.

Re: Tox: secure messaging for everyone

#50

Post by kostyakow »

unknownian wrote: post #38
kostyakow wrote: post #34

Earlier quoted context omitted.

>Github maintained by someone with a troll username? >Comments like this >> IMPORTANT: release two major sanctioned UIs, one for autists, one with inbuilt support for the previous list so that plebs can't get confused with setting it up and autists don't complain about it getting in their way. de geso > I would suggest a "Advanced options" where the autists can rejoice with all kinds of options (and it doesn't fright…

And another thing: /g/ in particular is known for much pointless banter arguing over the best GNU+Linux distro or giving minor tech support to non-natives of /g/. Attempts have been made before to make something substantial on the board and this time it seems we can do it.

>/g/ in particular is known for much pointless banter arguing over the best GNU+Linux distro

You mean arguing about the second best GNU/Linus distro. Everyone knows the best distro is Gentoo.

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