def sign(identity, data)
info = known_identities[identity] or raise KeyManagerError, "the given identity is unknown to the key manager"
if info[:key].nil? && info[:from] == :file
begin
info[:key] = KeyFactory.load_private_key(info[:file], options[:passphrase])
rescue Exception => e
raise KeyManagerError, "the given identity is known, but the private key could not be loaded: #{e.class} (#{e.message})"
end
end
if info[:key]
return Net::SSH::Buffer.from(:string, identity.ssh_type,
:string, info[:key].ssh_do_sign(data.to_s)).to_s
end
if info[:from] == :agent
raise KeyManagerError, "the agent is no longer available" unless agent
return agent.sign(identity, data.to_s)
end
raise KeyManagerError, "[BUG] can't determine identity origin (#{info.inspect})"
end