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"Oh good, a bunch of randoms have rolled their own crypto. I stopped reading at this point." An ad-hominem attack. This is Hacker News and their work is open,

"Oh good, a bunch of randoms have rolled their own crypto. I stopped reading at this point." An ad-hominem attack. This is Hacker News and their work is open, how about making a statement after researching the actual code instead?

micheljansen 13y ago
In this case, even if you remove the ad-hominem attack (a bunch of randoms), a valid point remains: implementing crypto is already notoriously difficult, let alone designing cryptographic protocols.
- TelegramApp 13y ago
  Still, there are sometimes valid reasons for not re-using existing solutions. In our case, we needed something that is both secure and competitive in comparison to mass market solutions in terms of speed, working on weak connections and usability. Disclaimer: I work for Telegram.
  - ge0rg 13y ago
    It is a really bad idea to compromise security for speed and connection stability. Processing power is a question of scaling the hardware, communication speed is hardly affected by a proper encryption scheme, neither is reliability of the application-layer protocol. Usability, however, is a different beast. You must compromise security to make a chat application appeal to "regular" users. Still, this is a trade-off that can be clearly communicated to the user and to developers, and does not require a custom crypto protocol. You can achieve the same effects with using existing and tested libraries. Edit: Disclaimer: I am the developer of the yaxim Android XMPP client and the operator of the public yax.im XMPP server (both available at http://yax.im http://yax.im).
    - e12e 13y ago
      Thank you for the plug for yaxim. I've been searching around for a "good enough" jabber client for android, and while yaxim isn't there yet (for me: no otr support, single server) it looks like it's headed in the right direction!
      - finnn 13y ago
        Have you looked at ChatSecure? It has OTR, multiple servers, all that good stuff. It's not wonderful but it ain't bad (curious to hear what others have to say, I haven't really used much else)
        e12e 13y ago
        I have it installed, but not really looked at it. My last "burst" use of xmpp was via facebook -- as most of my contacts don't use "plain" jabber right now. Before that I used it a bit for work -- but then rarely on my phone. Now that google is killing talk in favour of proprietary hangouts, I predict it'll be a while before I'm a serious xmpp user again. Sadly it's very hard to push process changes when one are in the minority in a group... Thanks for the reminder though, it does look like it full-fills most of my needs (and fixes annoyances I've encountered with other android clients).
    - TelegramApp 13y ago
      MTProto still uses RSA, AES + DH. So I would disagree that what we have here means 'compromising security for speed and stability'. It is rather optimizing for speed and stability, while staying secure.
      - ska 13y ago
        Often in the crypto world, these are exactly the good intentions with which the road to hell(pwnage?) is paved. Knowing this, I hope you can appreciate why the burden of proof on your unproven team and approach is fairly high.
  - e12e 13y ago
    How do you improve on OTR?
  - micheljansen 13y ago
    Absolutely, just trying to point out that the original poster raised some valid points that didn't deserved to be dismissed as "ad hominem". I haven't had a chance to dissect your work (but appreciate that you have made that possible in the first place) and I believe extraordinary claims require extraordinary scrutiny :)
richo 13y ago
You're assuming that the average HN is in a position to audit crypto code. We use well audited crypto primitives with formal proofs because they're known safe, or at least orders of magnitude safer than whatever these fools cooked up. tl;dr provide proof or gtfo. We're not here to audit you.
Morgawr 13y ago
If there is one place where an appeal to authority argument can hold place and not be seen as a fallacy is security. (it's not ad hominem btw) When you're rolling out a secure system + implementation you want to use algorithms that have been proven, tested and certified as correct. It's a delicate field that can't be approached like your standard software development field. Yes, being a "random" and developing your own encryption algorithm out of the box is bad. Never trust anything like that. Period.
DanBC 13y ago
Why bother reviewing the code? It's almost certainly a waste of time to do so. We know that writing crypto is hard and experienced crypto programmers make mistakes. The possibility of a naive programmer creating a sturdy piece of crypto software with no previous experience is vanishingly small.

micheljansen 13y ago

In this case, even if you remove the ad-hominem attack (a bunch of randoms), a valid point remains: implementing crypto is already notoriously difficult, let alone designing cryptographic protocols.

TelegramApp 13y ago
Still, there are sometimes valid reasons for not re-using existing solutions. In our case, we needed something that is both secure and competitive in comparison to mass market solutions in terms of speed, working on weak connections and usability. Disclaimer: I work for Telegram.
- ge0rg 13y ago
  It is a really bad idea to compromise security for speed and connection stability. Processing power is a question of scaling the hardware, communication speed is hardly affected by a proper encryption scheme, neither is reliability of the application-layer protocol. Usability, however, is a different beast. You must compromise security to make a chat application appeal to "regular" users. Still, this is a trade-off that can be clearly communicated to the user and to developers, and does not require a custom crypto protocol. You can achieve the same effects with using existing and tested libraries. Edit: Disclaimer: I am the developer of the yaxim Android XMPP client and the operator of the public yax.im XMPP server (both available at http://yax.im http://yax.im).
  - e12e 13y ago
    Thank you for the plug for yaxim. I've been searching around for a "good enough" jabber client for android, and while yaxim isn't there yet (for me: no otr support, single server) it looks like it's headed in the right direction!
    - finnn 13y ago
      Have you looked at ChatSecure? It has OTR, multiple servers, all that good stuff. It's not wonderful but it ain't bad (curious to hear what others have to say, I haven't really used much else)
      - e12e 13y ago
        I have it installed, but not really looked at it. My last "burst" use of xmpp was via facebook -- as most of my contacts don't use "plain" jabber right now. Before that I used it a bit for work -- but then rarely on my phone. Now that google is killing talk in favour of proprietary hangouts, I predict it'll be a while before I'm a serious xmpp user again. Sadly it's very hard to push process changes when one are in the minority in a group... Thanks for the reminder though, it does look like it full-fills most of my needs (and fixes annoyances I've encountered with other android clients).
  - TelegramApp 13y ago
    MTProto still uses RSA, AES + DH. So I would disagree that what we have here means 'compromising security for speed and stability'. It is rather optimizing for speed and stability, while staying secure.
    - ska 13y ago
      Often in the crypto world, these are exactly the good intentions with which the road to hell(pwnage?) is paved. Knowing this, I hope you can appreciate why the burden of proof on your unproven team and approach is fairly high.
- e12e 13y ago
  How do you improve on OTR?
- micheljansen 13y ago
  Absolutely, just trying to point out that the original poster raised some valid points that didn't deserved to be dismissed as "ad hominem". I haven't had a chance to dissect your work (but appreciate that you have made that possible in the first place) and I believe extraordinary claims require extraordinary scrutiny :)

richo 13y ago

You're assuming that the average HN is in a position to audit crypto code. We use well audited crypto primitives with formal proofs because they're known safe, or at least orders of magnitude safer than whatever these fools cooked up. tl;dr provide proof or gtfo. We're not here to audit you.

Morgawr 13y ago

If there is one place where an appeal to authority argument can hold place and not be seen as a fallacy is security. (it's not ad hominem btw) When you're rolling out a secure system + implementation you want to use algorithms that have been proven, tested and certified as correct. It's a delicate field that can't be approached like your standard software development field. Yes, being a "random" and developing your own encryption algorithm out of the box is bad. Never trust anything like that. Period.

DanBC 13y ago

Why bother reviewing the code? It's almost certainly a waste of time to do so. We know that writing crypto is hard and experienced crypto programmers make mistakes. The possibility of a naive programmer creating a sturdy piece of crypto software with no previous experience is vanishingly small.