Take a look at
http://www.obviex.com/Articles/CiphertextSize.aspx there is a really good article on calculating the size of database fields required to store encrypted strings.
Just calc how much space is required for the Rijndael encryption using the calculation given, build a string that big, convert to base 64 and see how big it is...
- Craig
"If you're not prepared to be wrong, you will never come up with anything original."
- Sir Ken Robinson
