Password text hider

Okay so I made a program that locks your computer and requires you to type in your password so resume your computer. I can't seem to figure out how to change the pasword text from text to a star *. I've tried

local input = ("*")

, but that does not work. Any suggestions? Heres the code i've got so far:

os.pullEvent = os.pullEventRaw
print ("Computer Locked")
print ("Locker v0.9.8")
print ("Username: viper151")
textutils.slowPrint ("To unlock this computer get the user who locked the computer to enter his/her password, or contact a   system administrator.")
local password = ""
while password ~= "youtube" do
  term.write ("Password: ")
  password = read()
end
print ("Computer Unlocked")

read() takes an optional character that it will write instead of the pressed key. An example:

term.write("Password: ")
password = read("*")

thank you, I have no idea why i didn't try that thanks!! :)/>