This will be a very fast and simple tutorial of how to make a passworded door. Make sure to have some understanding in lua before adding the security line

os.pullEvent = os.pullEventRaw

at the top of your program. Let's get going.

-- Easy Passworded Door
-- Written by Galxis
-- Posted to The TekkitLite Wiki on 19/01/2013

term.setCursorPos(1, 1)   -- Those commands will just clear the screen

print("Simple Password Door v. 1.2")
write("Enter password: ")
input = read(*)    -- This is the input the user makes, printed as *

password = "TekkitLite"    -- This is the correct password, and can be anything.

if input == password then   -- If the input is equal to the password then...
  print("Password was correct!")
  rs.setOutput("left", true)
  rs.setOutput("left", false)
else           -- If input isnt equal to password then...
  print("Password was incorrect")

Here we go :D

Be aware that Ctrl+T and the edit command could still be used to bypass this program.