Why key type ecdsa-sha2-nistp256 is unsupported? - jruby

Question

I'am trying to use ruby gem net-ssh and receive the error described bellow
jruby-9.1.15.0 :001 > require "net/ssh"
=> true
jruby-9.1.15.0 :002 > Net::SSH.start('myhost.dev', 'username' password: 'password', verbose: Logger::DEBUG){|ssh| puts ssh.exec!('hostname')}
D, [2018-01-17T14:24:29.633089 #26123] DEBUG -- net.ssh.transport.session[7d0]: establishing connection to myhost.dev:22
D, [2018-01-17T14:24:29.884816 #26123] DEBUG -- net.ssh.transport.session[7d0]: connection established
I, [2018-01-17T14:24:29.888234 #26123] INFO -- net.ssh.transport.server_version[7d2]: negotiating protocol version
D, [2018-01-17T14:24:29.888926 #26123] DEBUG -- net.ssh.transport.server_version[7d2]: local is `SSH-2.0-Ruby/Net::SSH_4.2.0 java'
D, [2018-01-17T14:24:29.952538 #26123] DEBUG -- net.ssh.transport.server_version[7d2]: remote is `SSH-2.0-OpenSSH_6.6.1p1 Ubuntu-2ubuntu2.8'
NotImplementedError: unsupported key type `ecdsa-sha2-nistp256'
from /home/qpi/.rvm/gems/jruby-9.1.15.0#some_gem/gems/net-ssh-4.2.0/lib/net/ssh/buffer.rb:286:in `read_keyblob'
Error was raised from buffer.rb:286:in read_keyblob.
Here the part of code which raising the error
unless defined?(OpenSSL::PKey::EC)
raise NotImplementedError, "unsupported key type `#{type}'"
Ok.. lets check, defined OpenSSL::PKey::EC or not:
jruby-9.1.15.0 :003 > defined?(OpenSSL::PKey::EC) ? 'defined' : 'not defined'
=> "defined"
What am I doing wrong?
When i use ruby (not jruby), everything works fine

Answer 1

Not a real solution but I found a hack that does the trick for me.
https://github.com/jruby/jruby-openssl/issues/105
In short, before your Net::SFTP.start, put these 2 lines.
Net::SSH::Transport::Algorithms::ALGORITHMS.values.each { |algs| algs.reject! { |a| a =~ /^ecd(sa|h)-sha2/ } }
Net::SSH::KnownHosts::SUPPORTED_TYPE.reject! { |t| t =~ /^ecd(sa|h)-sha2/ }
and your problem should be gone.