Is there a way to compress small string ( 100 char ) to about ( 20 char ) BY C# ?

Question

I search for a way to compress small string ( 100 char ) to a string in about (15-25) char that allow me to decompress it again ?
UPDATE:
string is just a text and i'll not store it
I just want to pass a string of about 100 char from asp.net web page to another web page in a query string so i want to compress it first before pass it in query string as it's length may be from 100 to 200 char
I don't want use session variables to pass it I want to use query string