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Telegram’s Cryptanalysis Contest

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Re: Telegram’s Cryptanalysis Contest

#91

Post by girvo »

seertaak wrote: post #56
tptacek wrote: post #49

Earlier quoted context omitted.

That would be nice. But, for what it's worth: don't use Telegram. It's a mess. TextSecure was built much, much more carefully.

Is TextSecure only for SMS messages, or does it use the internet? I'm asking because of the need to send text messages abroad (at a reasonable price). Also, is there a desktop client for TextSecure? I would love something like WhatsApp -- but secure and with a desktop client.

XMPP + OTR will do what you want. I asked moxie the same question re the internet vs text, but he hasn't replied yet. As far as I'm aware it uses text for insecure stuff, and I think for initial key exchange to start the ratchet then uses the internet for secure messaging. Its quite user friendly. No desktop client, and the messages are of ephemeral so keep that in mind and see whether that's okay for your use case (it is for mine).

Re: Telegram’s Cryptanalysis Contest

#92

Post by girvo »

sillysaurus2 wrote: post #45
Nursie wrote: post #32

Earlier quoted context omitted.

So you didn't understand the article here then? There's no shame on that, crypto is complex and requires study. But please don't dismiss well written and well thought-out critiques like this one just because you didn't understand the arguments.

Talking down to people helps nobody. If I were a random potential user and read what you wrote, my reaction would not be polite, and I would probably feel polarized against your recommendation out of spite. The problem isn't that potential users are lacking anything. It's that nobody on our side of the table has communicated clearly and succinctly. https://news.ycombinator.com/item?id=6941007

With all respect, crypto (and broken crypto) is wrt difficult to explain in a user friendly way to a lay person without just ignoring the technical details. Once you do that, it really is just "fuck telegram use snapchat", which doesn't help anyone... I am going to give it a bash tomorrow to try and write the article you are after. Good technical writing practice :)

What makes the Article here not sufficient from your perspective?

Re: Telegram’s Cryptanalysis Contest

#93

Post by ibudiallo »

So everyone is mad cause they used their own approach to security. Now no one managed to break their crypto so far. Don't say it is bad unless you can break it. Don't go around write a full paper about how bad it is while you still can't break it.

I still don't get why there is all this hostility toward telegram.

Re: Telegram’s Cryptanalysis Contest

#94

Post by girvo »

vitalyny wrote: post #68
jaxb wrote: post #60

Earlier quoted context omitted.

So are you associated with telegram, just to be clear?

Sorry I didn't respond to that. No, I'm not associated with Telegram in any way. And I'm not crypto professional :) I totally understand what Telegram critics are saying, but in every article there's always a note "Please use TextSecure, don't use Telegram". By how it looks, it seems to be a way to market TextSecure and not to discover Telegram's security flaws. And critics rarely respond to Telegram team's comments…

TextSecure is in my (and that of crypto professionals who opinions I respect immensely) opinion the best secure messaging app on the market today -- and what they've achieved is a very difficult thing to do, as Telegram sort of shows. It's not about "hating" one or the other, this is maths and trust. TextSecure has proven maths and has spent a lot of time and effort (and open sourced their code) to build that trust and address all the issues these types of apps face.

When you're dealing with a market that can have literal life or death consequences, you go with something proven. That's why everyone touts it instead.

Re: Telegram’s Cryptanalysis Contest

#95

Post by kbenson »

nly wrote: post #89
kbenson wrote: post #71

Earlier quoted context omitted.

which are easy to understand and reason about but I know for a fact weren't designed by world class crypto-experts I though Satoshi was anonymous? Do you know something the rest of us don't, or are you making assumptions on the code (and if so, how can you make those assumptions when you also state it was a success)?

The extensions I'm talking about were added long after Satoshi left the project.

Okay, fair enough. I'm curious about the what makes you sure they weren't written by experts though. Do you have knowledge of the implementers that points towards them not being experts?

Re: Telegram’s Cryptanalysis Contest

#96

Post by dcalacci »

ibudiallo wrote: post #93

So everyone is mad cause they used their own approach to security. Now no one managed to break their crypto so far. Don't say it is bad unless you can break it. Don't go around write a full paper about how bad it is while you still can't break it. I still don't get why there is all this hostility toward telegram.

>So everyone is mad cause they used their own approach to security

No, that's not why people are upset at all.

People are upset because whether or not someone has been able to break their system under the constraints of the contest means almost nothing.

Did you even read the article?

Re: Telegram’s Cryptanalysis Contest

#97

Post by B-Con »

vitalyny wrote: post #68
jaxb wrote: post #60

Earlier quoted context omitted.

So are you associated with telegram, just to be clear?

Sorry I didn't respond to that. No, I'm not associated with Telegram in any way. And I'm not crypto professional :) I totally understand what Telegram critics are saying, but in every article there's always a note "Please use TextSecure, don't use Telegram". By how it looks, it seems to be a way to market TextSecure and not to discover Telegram's security flaws. And critics rarely respond to Telegram team's comments…

> but in every article there's always a note "Please use TextSecure, don't use Telegram".

This is very common in the security field.

Good crypto/security software is often not very straight-forward for the public to find. They're usually run by competent developers doing the work for free and don't tend to have big PR budgets or do a lot of advertising. The product is findable, but they can be overshadowed by snake-oil products that focus on the business aspects.

Whenever a security project or service is attacked as insecure, the natural question is "what do you use instead?", particularly if the functionality was niche or unique. It's just a part of the community that an alternative good one is recommended. We try to avoid saying "don't use X" and instead say "don't use X, but do use Y".

Yes, it helps Y piggie-back a bit off the popularity of X, but that's Y's fault being being bad enough to be disparaged. It isn't just the TextSecure team doing this, it's everyone who cares about this type of service.

Re: Telegram’s Cryptanalysis Contest

#98

Post by sheetjs »

sillysaurus2 wrote: post #31
adcoelho wrote: post #23

Earlier quoted context omitted.

Yesterday's article A Crypto Challenge For The Telegram Developers was a good analysis on why Telegram's challenge fails to prove anything.

Sadly, it was probably too technical for most potential users to be swayed much by it. We need focused talking points, e.g. the fact that the NSA and other governments vacuum up all your data, and that TextSecure represents the first step toward a future in which it's very difficult for governments to do that. Whereas with Telegram, it's just as easy for them to access your conversations as it is for them to bypass S…

Simpler explanation:

I am selling fire-proof safes. These are designed to protect your documents and valuables from thieves and from fire and other events.

The normal way people set up tests is to put some documents and valuables in a box and actually try to break it (MythBusters style, bringing out cool machinery and trying different ways). For fire resistance, there is a rating system (https://en.wikipedia.org/wiki/Fire-resistance_rating) and a standard way to test.

The Telegram proposition is: we are going to place the safe in Fort Knox. If you can't break the safe that is in Fort Knox, then clearly our safe is secure.

The Article rebuttal: to break the safe, you have to break into Fort Knox. And for all intents and purposes that's not going to happen. You could have put a cardboard box and no one could tell the difference because of how you structured the test.

Re: Telegram’s Cryptanalysis Contest

#99

Post by mcguire »

Not necessarily on topic, but...

"... will give $200,000 in BTC to the first person ..."

Is that $200,000 in BTC at the time the contest was announced, or at the time the winner is announced? Or at some other point?

(This comment brought to you by the Committee For Pointing Out That A Currency That Wildly Fluctuates In Value Is Not Particularly Useful (CFPOTACTWFIVINPU).)

Re: Telegram’s Cryptanalysis Contest

#100

Post by kbenson »

tptacek wrote: post #76
TelegramApp wrote: post #52

The contest, as proposed by Pavel, while limited for the moment, does cover an important issue as far as our users are concerned. And the scope will naturally expand with time, should Telegram be invulnerable under the current conditions (see contest FAQ: http://core.telegram.org/contestfaq ). Quoting a post by Pavel here on HN: "Telegram will always be interested in creating incentives for the crypto-community to ch…

I'm worried that to people unfamiliar with modern crypto, the diagram of your protocol and the "technical FAQ" might sound credible or even convincing. But it is not. The message integrity protection this system describes is not up to modern standards. The system seems to use SHA1, which is a fault for a new system (no new system should use SHA1), but that's not the biggest problem; the biggest problem is that the SH…

Okay, here's an authority I can get behind on this debate, not being familiar enough myself to parse most of the criticisms for their veracity. I don't always agree with your political or economic take on a subject, but I've never seen anything but excellence in your technical breakdowns of a subject, especially cryptography (go figure ;).

80% of the RSA implementations on the Internet are insecure because they use the default padding

So, now that I've hopefully buttered you up enough, I'm hoping you have a reference to share, because if that's true, it's pretty damn scary.

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