#Cryptocat csecurity update#
#Cryptocat csecurity code#
#Cryptocat csecurity crack#

Thomas said on his blog that Cryptocat has tried numerous encryption iterations, including RSA, Diffie-Hellman and ECC, but uses key sizes smaller than the minimums.

#Cryptocat csecurity crack#

Doing a 2*10^8 and 10^8 split it will take an hour to generate and half an hour to crack any private key with that data.” This only requires tens of gigabytes to store. “For Cryptocat versions before 2.0.42, doing a split of 2*10^9 and 10^7 it takes about a day to calculate data needed to crack any key in few minutes. “Decryptocat takes advantage of a meet-in-the-middle attack called baby-step giant-step you can effectively square root the key space. He added that changes made to the keyspace in Cryptcocat version 2.0.42 raises that timeframe to 1,000 computer years of calculations. Using a meet-in-the-middle attack, which reduces the number of brute force attempts needed to crack a target, Thomas said his tool can crack a key in less than two hours of computing time. Thomas disagrees and says the bug has been present since October 2011, and wrote an app called DecryptoCat that cracks the ECC public keys generated by Cryptocat between versions 1.1.147 and 2.0.41. “Group conversations that were had during those seven months were likely vulnerable to being significantly easier to crack,” Cryptocat said on its development blog.

#Cryptocat csecurity update#

Cryptocat, meanwhile, says the vulnerability was present between versions 2.0 and 2.0.42-a seven-month timeframe-and urges users to update the app to the 2.1 branch.

#Cryptocat csecurity code#

Worse, says researcher Steve Thomas who found the flaw, is that it likely was present in the code base going back to 2011. TLDR: If you used group chat in Cryptocat from October 17th, 2011 to June 15th, 2013 assume your messages were compromised.ĭSA is probably broken in one-to-one chat over OTR.Cryptocat, an open source encrypted Web-based chat application, is taking heat from numerous places after a vulnerability was discovered that put chats at risk for relatively simple decryption, experts say. You must update Cryptocat to at least 2.1.12 to be safe from known problems. Here is the old post where I was less nice (it is a longer read with a little more detail). October 17th, 2011 Diffie-Hellman private keys were reduced to crackable. May 7th, 2012 ECDH introduced and is broken with DecryptoCat.Īpril 19th, 2013 ECDH is no longer easy to break, but still crackable by governments and large companies. June 3rd, 2013 I patched ECDH now private keys are uncrackable. June 15th, 2013 FireFox approves first 2.x version of Cryptocat that is not using short ECDH private keys.ĭecryptoCat v0.1 cracks the group chat ECDH public keys generated by Cryptocat versions 1.1.147 through 2.0.41.Ĭryptocat version 2.0.42 was released which increased the key space from 2^54.15 to 2^106.3.ĭecryptocat takes advantage of a meet-in-the-middle attack called baby-step giant-step you can effectively square root the key space.

So 2^54.15 turns into 2^27.08 and 2^106.3 to 2^53.15.įor Cryptocat versions before 2.0.42, doing a split of 2*10^9 and 10^7 it takes about a day to calculate data needed to crack any key in few minutes.