access
chrome
close
code
combination
confidential
dial
entry
illustration
isolated
key
lock
login
metal
number
open
password
permission
personal
polish
private
professional
protect
protection
puzzle
realistic
restricted
rotate
safe
safety
secrecy
secret
secure
secured
security
sequence
shiny
silver
solution
steal
steel
system
theft
theftproof
turn
unlock
vault
wheel