How to encrypt URL Address ?

Now i 'm play about PHP language .
and now i want ot know how to " advance url display "
like encrypt URL Address in browser ( IE , Opera , others )

like Display ::

http://posting.google.com/post?cmd=post&justr=
http://127.0.0.1:4664/&s=yC1WvvwfhpLmt75SPkYGMFFgmsw
http://www.google.com/grphp?hl=th&tab=ig&q=

...