# File lib/net/ssh/known_hosts.rb, line 87
    def keys_for(host)
      keys = []
      return keys unless File.readable?(source)

      entries = host.split(/,/)

      File.open(source) do |file|
        scanner = StringScanner.new("")
        file.each_line do |line|
          scanner.string = line

          scanner.skip(/\s*/)
          next if scanner.match?(/$|#/)

          hostlist = scanner.scan(/\S+/).split(/,/)
          next unless entries.all? { |entry| hostlist.include?(entry) }

          scanner.skip(/\s*/)
          type = scanner.scan(/\S+/)

          next unless %w(ssh-rsa ssh-dss).include?(type)

          scanner.skip(/\s*/)
          blob = scanner.rest.unpack("m*").first
          keys << Net::SSH::Buffer.new(blob).read_key
        end
      end

      keys
    end