AIMS to capture confidentiality read requirements only thesystem is modelled as transitoins through a set of states
a state is secure if simple security property ( ss ) no subject may read data at a higher level ( NO read up) the * (star) property, no subject may write data at a lower level ( NO Write down ) need both
file access subjects s1 ( e.g. proc_a and s2 ( e.g. proc b ))
intro to web arguments are passed after a path via name=value pairs
fragments are located after a # sign not sent to a web server only used by the web browser
url encoding notation: % followed by hexadecimal value of the character %20 is spacebar %35 # %50 is 2