Most  large  institutions  do  not  want  their  employees  to  carry  around  large  quantities  of  keys.  Similarly,  these  institutions  would  like  to  restrict  access  based  on  an  individual’s  standing,  and  responsibility,  within  the  establishment.  A  master  key  system  will  allow  for  different  levels  of  restricted  entry.  When  a  master  key  system  is  finished  there  may  be  a  graduated  level  of  access.  In  the  example  of  a  property  manager,  one  tenant’s  key  will  work  on  their  lock  but  not  on  the  neighbor’s  lock.  However,  the  property  manager  will  have  one  key  that  works  for  both  locks.  This  can  work  to  create  a  number  of  possible  keys.