client.rb

# with comments

def get_random_bytes count
  random = `dd if=/dev/urandom | head -c #{count}`
  puts "random data is:\n#{random}\n\r-----length is: #{random.length}"
  random  
end

def clip_encoded_with data_str, encoding
    encoded = data_str.encode(encoding, invalid: :replace, undef: :replace, replace: '')
    puts "encoded string is:\n#{encoded}\n\r-----length is: #{encoded.length}"
	encoded
end

def replace_chars data_str, match_code, replacement	
    replaced = data_str.each_byte.map.with_index do |b, i|
    	b == match_code ? replacement : data_str[i] 
    end.join
	puts "replaced string is:\n#{replaced}\n\r-----length is: #{replaced.length}"
	replaced
end

def send_socket host, port, data
  require 'socket'
  sock = TCPSocket.new(host, port)
  sock.write data
  sock.close
end


# read 1024 byes from /dev/urandom:
random = get_random_bytes 1024
# remove not UTF-8 chars
utf8 = clip_encoded_with random, 'UTF-8'
# replace spaces with asterisk
replaced = replace_chars utf8, 32, '*'
# send data to TCP server
send_socket 'localhost', 2345, replaced

sockserver.rb

require 'socket' 
server = TCPServer.new('localhost', 2345)
loop do
  socket = server.accept
  request = socket.gets
  STDERR.puts request
end