PhpStorm: Algorithm negotiation fail
I had the same problem. I solved this problem by adding
KexAlgorithms curve25519-sha256@libssh.org,ecdh-sha2-nistp256,ecdh-sha2-nistp384,ecdh-sha2-nistp521,diffie-hellman-group-exchange-sha256,diffie-hellman-group14-sha1,diffie-hellman-group1-sha1
to
/etc/ssh/sshd_configand after that, I restart sshd
sudo systemctl restart sshd
Just upgraded Ubuntu to 16.04 and encountered this issue, the "Algorithm negotiation fail" in PHPStorm 8.0.3.
The problem is with the jsch-0.1.51.jar library. If you overwrite the jsch-0.1.51.jar file with the latest from https://sourceforge.net/projects/jsch/ (currently jsch-0.1.54.jar) and restart, it should be fine. No need to add insecure algorithms to your ssh daemon.
As Guillaume Fache proposed, minimal configuration for PhpStorm is:
KexAlgorithms diffie-hellman-group1-sha1
but diffie-hellman-group1-sha1 use:
1) 1024 bits modulus - breakable, marked as insecure
2) SHA-1 - breakable, confirmed collision attack possibility
conclusion:
use public/private key pair - more secure and no needs to save or type password
