6 ms·

Dear Cryptocat Users

122 points by sdevlin 11y ago

tptacek 11y ago
This is a good thing, though I think it should have happened more than 19 months earlier. Cryptocat wasn't just unmaintained†, but also gravely flawed and insecure. † Despite looking like this yesterday: https://web.archive.org/web/20160205030908/http://crypto.cat/ https://web.archive.org/web/20160205030908/http://crypto.cat...
- conorgil145 11y ago
  Links to resources, papers, or articles which discuss the flaws in CryptoCat?
  - sdevlin 11y ago
    https://tobtu.com/decryptocat.php https://tobtu.com/decryptocat.php
    - tptacek 11y ago
      (among other things)
- deleted 11y ago
  [deleted]
sbierwagen 11y ago
Some context, if you don't know what cryptocat is, or why the lead dev is shutting it down: Cryptocat Considered Harmful (2013) https://datavibe.net/~sneak/20130717/cryptocat-considered-harmful/ https://datavibe.net/~sneak/20130717/cryptocat-considered-ha... Except: Today, Cryptocat is not for everyone. Cryptocat is under active development, and is suitable only for debugging and software experimentation. It is not suitable for those who desire communications privacy. (This may change 2-5 years in the future, following sufficient peer review.) Cryptocat has had myriad errors in implementation, spanning the entire time it has been under active development. Note well that this is not a criticism: cryptosystems are notoriously difficult to get right, and it takes a very long time, significant experience, much peer review (on top of that significant experience), and lots of sweat and iteration to build systems that are safe to use. (HN thread on that post: https://news.ycombinator.com/item?id=6990602 https://news.ycombinator.com/item?id=6990602 ) Schneier post on the adoring media coverage of cryptocat (2012) https://www.schneier.com/blog/archives/2012/08/cryptocat.html https://www.schneier.com/blog/archives/2012/08/cryptocat.htm...
rosalinekarr 11y ago
Cryptocat is one of those awesome projects I'd love to support, but I just don't have the time or expertise to help. I hope Kobeissi finds some good devs to help him keep the project going.
sarciszewski 11y ago
Cryptocat was a good concept (i.e. it was USABLE!), but the execution was flawed. It grew a lot of criticism and Nadim made mistakes in handling some of his critics, creating a schism between him and the cryptographers who might have been able to help him. (Not all of this was his fault, of course.) I hope that not only will this new product of his be developed with "A pure vision of democratized, pleasant secure messaging", but also that he has matured significantly. I hope that Cryptocat v3 will come out after it has been thoroughly audited by several reputable third parties. Most importantly, I hope their crypto is boring. https://security.stackexchange.com/questions/6095/xkcd-936-short-complex-password-or-long-dictionary-passphrase/6116#6116 https://security.stackexchange.com/questions/6095/xkcd-936-s... http://cr.yp.to/talks/2015.10.05/slides-djb-20151005-a4.pdf http://cr.yp.to/talks/2015.10.05/slides-djb-20151005-a4.pdf
- tptacek 11y ago
  What does it matter if a secure messenger is USABLE if it's not secure? Cryptocat wasn't.
  - nfd 11y ago
    A usable, secure messenger is a pretty important niche to fill. Cryptocat is a good concept (usability is important), but its implementation is flawed enough that it's worse than useless. With some TLC, better ground-up design, and through auditing? Pretty sweet. There isn't one messenger that fills every niche reasonably well (eg. Tox is fragmented and hasn't been audited as far as I'm aware, Jitsi is clunky and relies heavily on outside services, Retroshare requires an intricate knowledge of GPG, several other messengers sit over Tor which requires education, and libpurple is garbage, etc.).
    - tptacek 11y ago
      I completely agree that a usable, secure messenger is important!
      - middleclick 11y ago
ocfx 11y ago
Add this to the list of projects he has walked away from that people were using
uobytx 11y ago
Any word on the status of minilock? It also hasn't seen public activity on github for some time.
samstave 11y ago
This is not the same as the cryptocat scanner from ~2004?
- robbiet480 11y ago
  Were you thinking of CueCat? https://en.wikipedia.org/wiki/CueCat https://en.wikipedia.org/wiki/CueCat
  - samstave 11y ago
    DOH! - Yes, thats what I was thinking of... Thank you.
tootie 11y ago
Is end-to-end encrypted messaging really that hard? Assuming you simply forgo all the features that require a server and just send messages peer-to-peer using TLS, isn't this pretty straightforward to do?
- SomeCallMeTim 11y ago
  It's not hard to encrypt the messages if you use an existing, secure library to do the work. What's hard is making it impossible for someone other than the intended recipient to decrypt the message. How do you get the key to the recipient? Using something like a secure chat? Oops, that's what you're trying to create. Maybe DH key exchange? [1] It's not rocket science to implement, but mistakes are possible. Also, unless you're sure that you're talking directly to the person you think you are, a MITM could be performing the key exchange with each end, and again you have someone overhearing you. So in addition to a proper DH implementation you need some way for the people to verify that the tokens exchanged match. tl;dr: Yes, it's really that hard. [1] https://en.wikipedia.org/wiki/Diffie%E2%80%93Hellman_key_exchange https://en.wikipedia.org/wiki/Diffie%E2%80%93Hellman_key_exc...
- JshWright 11y ago
  Peer discovery is an interesting problem to solve in this case... Encrypting the message is easy. Delivering it reliably without some sort of server is a bit more challenging...
  - tootie 11y ago
    Is using a server for discovery and key exchange so terrible? The messages will still never touch it.
Thanatos26FF 11y ago
Hey guys, I am an avid user of Cryptocat and have been using it for over a year. I am sad to see Cryptocat will be down for the foreseeable future, but I have found an alternative which is even better. Cryptodog is looking to take off where Cryptocat left off and is constantly being worked on. It's still a work in progress, but I highly recommend it for everyone who wants to have private conversations
- tptacek 11y ago
  If you had a reliable Chrome zero day you wanted to burn to pop my dumb laptop (zero-day crypto challenges!), delivering it via a link to the new "Cryptodog" on a thread about Cryptocat would be a really funny way to own me up.
  - ayyghost 11y ago
    One of the Cryptodog devs here - no Chrome 0days in our possession (yet). The code's all on Github: https://github.com/Cryptodog/cryptodog https://github.com/Cryptodog/cryptodog. No signed extensions or apps yet, but you can clone and run locally for testing purposes, or use the hosted client linked there. So far, we've been focusing on refactoring, fixing surface bugs, and making the UI more attractive and intuitive -- none of the underlying cryptography has been touched. It also performs slightly faster than stock Cryptocat. Since Nadim took down his XMPP server, we've had to create our own, but the backend is identical to his setup. Of course, Cryptodog is by no means the best solution for E2E chat, just as Cryptocat wasn't. The best we can hope to achieve without a complete codebase overhaul is a reasonable level of security (https://leastauthority.com/static/publications/LeastAuthority-Cryptocat-audit-report.pdf https://leastauthority.com/static/publications/LeastAuthorit...). However, it's still a fairly usable app that can afford casual users protection against basic threats, like corporate data mining. Issue postings, pull requests, and other miscellaneous contributions are all welcome.
    - tptacek 11y ago
      Cryptocat was badly flawed and had at least one very serious undisclosed flaw before it was shut down. Do not try to build a secure messaging system from its code base.
chuckgreenman 11y ago
"There is a design decision that is not open for negotiation: it will be desktop-only. This is due to the my belief that the mobile space has been elegantly solved by other well-written open source software, while the desktop/laptop space could still use an alternative for usable, fun and secure messaging software, developed in the spirit of general purpose computing." By this logic, why even compete in the web/desktop space? Telegram has mobile, desktop and web clients.
- pigeons 11y ago
  He isn't talking about telegram, which isn't open source except the client.
  - skrowl 11y ago
    The protocol and crypto are also open source. The only thing about Telegram that isn't open source is the server. They've hinted that they might open the server and allow federating in the future, but they have no timeline for doing so.
isolusgraboski 11y ago
Good day! People on Cryptoca/Cryptodog will probably recognize me, but I would like to say. I think Cryptocat, no matter how good or bad it is, it is still a very good tool. Cryptodog is just an extension to that, and a good one, too. That is all I have to say.
- Thanatos26FF 11y ago
  I agree isolusgraboski, awesome name by the way. Cryptocat was a GREAT tool and Cryptodog is no different except with fixed flaws and programmer who care more deeply. I urge everyone to try it!
bunkydoo 11y ago
Ahh I remember using cryptocat long ago. Almost 3 years ago. Thanks for providing the service man! Hope to see more updates in the future
blubb-fish 11y ago
I simply love the idea of a transparently implemented encrypted communication through Facebook chat.

122 points by sdevlin 11y ago

This is a good thing, though I think it should have happened more than 19 months earlier. Cryptocat wasn't just unmaintained†, but also gravely flawed and insecure. † Despite looking like this yesterday: https://web.archive.org/web/20160205030908/http://crypto.cat/ https://web.archive.org/web/20160205030908/http://crypto.cat...

conorgil145 11y ago
Links to resources, papers, or articles which discuss the flaws in CryptoCat?
- sdevlin 11y ago
  https://tobtu.com/decryptocat.php https://tobtu.com/decryptocat.php
  - tptacek 11y ago
    (among other things)
deleted 11y ago
[deleted]

sbierwagen 11y ago

Some context, if you don't know what cryptocat is, or why the lead dev is shutting it down: Cryptocat Considered Harmful (2013) https://datavibe.net/~sneak/20130717/cryptocat-considered-harmful/ https://datavibe.net/~sneak/20130717/cryptocat-considered-ha... Except: Today, Cryptocat is not for everyone. Cryptocat is under active development, and is suitable only for debugging and software experimentation. It is not suitable for those who desire communications privacy. (This may change 2-5 years in the future, following sufficient peer review.) Cryptocat has had myriad errors in implementation, spanning the entire time it has been under active development. Note well that this is not a criticism: cryptosystems are notoriously difficult to get right, and it takes a very long time, significant experience, much peer review (on top of that significant experience), and lots of sweat and iteration to build systems that are safe to use. (HN thread on that post: https://news.ycombinator.com/item?id=6990602 https://news.ycombinator.com/item?id=6990602 ) Schneier post on the adoring media coverage of cryptocat (2012) https://www.schneier.com/blog/archives/2012/08/cryptocat.html https://www.schneier.com/blog/archives/2012/08/cryptocat.htm...

rosalinekarr 11y ago

Cryptocat is one of those awesome projects I'd love to support, but I just don't have the time or expertise to help. I hope Kobeissi finds some good devs to help him keep the project going.

sarciszewski 11y ago

Cryptocat was a good concept (i.e. it was USABLE!), but the execution was flawed. It grew a lot of criticism and Nadim made mistakes in handling some of his critics, creating a schism between him and the cryptographers who might have been able to help him. (Not all of this was his fault, of course.) I hope that not only will this new product of his be developed with "A pure vision of democratized, pleasant secure messaging", but also that he has matured significantly. I hope that Cryptocat v3 will come out after it has been thoroughly audited by several reputable third parties. Most importantly, I hope their crypto is boring. https://security.stackexchange.com/questions/6095/xkcd-936-short-complex-password-or-long-dictionary-passphrase/6116#6116 https://security.stackexchange.com/questions/6095/xkcd-936-s... http://cr.yp.to/talks/2015.10.05/slides-djb-20151005-a4.pdf http://cr.yp.to/talks/2015.10.05/slides-djb-20151005-a4.pdf

tptacek 11y ago
What does it matter if a secure messenger is USABLE if it's not secure? Cryptocat wasn't.
- nfd 11y ago
  A usable, secure messenger is a pretty important niche to fill. Cryptocat is a good concept (usability is important), but its implementation is flawed enough that it's worse than useless. With some TLC, better ground-up design, and through auditing? Pretty sweet. There isn't one messenger that fills every niche reasonably well (eg. Tox is fragmented and hasn't been audited as far as I'm aware, Jitsi is clunky and relies heavily on outside services, Retroshare requires an intricate knowledge of GPG, several other messengers sit over Tor which requires education, and libpurple is garbage, etc.).
  - tptacek 11y ago
    I completely agree that a usable, secure messenger is important!
    - middleclick 11y ago

ocfx 11y ago

Add this to the list of projects he has walked away from that people were using

uobytx 11y ago

Any word on the status of minilock? It also hasn't seen public activity on github for some time.

samstave 11y ago

This is not the same as the cryptocat scanner from ~2004?

robbiet480 11y ago
Were you thinking of CueCat? https://en.wikipedia.org/wiki/CueCat https://en.wikipedia.org/wiki/CueCat
- samstave 11y ago
  DOH! - Yes, thats what I was thinking of... Thank you.

tootie 11y ago

Is end-to-end encrypted messaging really that hard? Assuming you simply forgo all the features that require a server and just send messages peer-to-peer using TLS, isn't this pretty straightforward to do?

SomeCallMeTim 11y ago
It's not hard to encrypt the messages if you use an existing, secure library to do the work. What's hard is making it impossible for someone other than the intended recipient to decrypt the message. How do you get the key to the recipient? Using something like a secure chat? Oops, that's what you're trying to create. Maybe DH key exchange? [1] It's not rocket science to implement, but mistakes are possible. Also, unless you're sure that you're talking directly to the person you think you are, a MITM could be performing the key exchange with each end, and again you have someone overhearing you. So in addition to a proper DH implementation you need some way for the people to verify that the tokens exchanged match. tl;dr: Yes, it's really that hard. [1] https://en.wikipedia.org/wiki/Diffie%E2%80%93Hellman_key_exchange https://en.wikipedia.org/wiki/Diffie%E2%80%93Hellman_key_exc...
JshWright 11y ago
Peer discovery is an interesting problem to solve in this case... Encrypting the message is easy. Delivering it reliably without some sort of server is a bit more challenging...
- tootie 11y ago
  Is using a server for discovery and key exchange so terrible? The messages will still never touch it.

Thanatos26FF 11y ago

Hey guys, I am an avid user of Cryptocat and have been using it for over a year. I am sad to see Cryptocat will be down for the foreseeable future, but I have found an alternative which is even better. Cryptodog is looking to take off where Cryptocat left off and is constantly being worked on. It's still a work in progress, but I highly recommend it for everyone who wants to have private conversations

tptacek 11y ago
If you had a reliable Chrome zero day you wanted to burn to pop my dumb laptop (zero-day crypto challenges!), delivering it via a link to the new "Cryptodog" on a thread about Cryptocat would be a really funny way to own me up.
- ayyghost 11y ago
  One of the Cryptodog devs here - no Chrome 0days in our possession (yet). The code's all on Github: https://github.com/Cryptodog/cryptodog https://github.com/Cryptodog/cryptodog. No signed extensions or apps yet, but you can clone and run locally for testing purposes, or use the hosted client linked there. So far, we've been focusing on refactoring, fixing surface bugs, and making the UI more attractive and intuitive -- none of the underlying cryptography has been touched. It also performs slightly faster than stock Cryptocat. Since Nadim took down his XMPP server, we've had to create our own, but the backend is identical to his setup. Of course, Cryptodog is by no means the best solution for E2E chat, just as Cryptocat wasn't. The best we can hope to achieve without a complete codebase overhaul is a reasonable level of security (https://leastauthority.com/static/publications/LeastAuthority-Cryptocat-audit-report.pdf https://leastauthority.com/static/publications/LeastAuthorit...). However, it's still a fairly usable app that can afford casual users protection against basic threats, like corporate data mining. Issue postings, pull requests, and other miscellaneous contributions are all welcome.
  - tptacek 11y ago
    Cryptocat was badly flawed and had at least one very serious undisclosed flaw before it was shut down. Do not try to build a secure messaging system from its code base.

chuckgreenman 11y ago

"There is a design decision that is not open for negotiation: it will be desktop-only. This is due to the my belief that the mobile space has been elegantly solved by other well-written open source software, while the desktop/laptop space could still use an alternative for usable, fun and secure messaging software, developed in the spirit of general purpose computing." By this logic, why even compete in the web/desktop space? Telegram has mobile, desktop and web clients.

pigeons 11y ago
He isn't talking about telegram, which isn't open source except the client.
- skrowl 11y ago
  The protocol and crypto are also open source. The only thing about Telegram that isn't open source is the server. They've hinted that they might open the server and allow federating in the future, but they have no timeline for doing so.

isolusgraboski 11y ago

Good day! People on Cryptoca/Cryptodog will probably recognize me, but I would like to say. I think Cryptocat, no matter how good or bad it is, it is still a very good tool. Cryptodog is just an extension to that, and a good one, too. That is all I have to say.

Thanatos26FF 11y ago
I agree isolusgraboski, awesome name by the way. Cryptocat was a GREAT tool and Cryptodog is no different except with fixed flaws and programmer who care more deeply. I urge everyone to try it!

bunkydoo 11y ago

Ahh I remember using cryptocat long ago. Almost 3 years ago. Thanks for providing the service man! Hope to see more updates in the future

blubb-fish 11y ago

I simply love the idea of a transparently implemented encrypted communication through Facebook chat.