So i have a form that on paper is 40 pages long. I was going to take the natural sections of this form, and make separate html forms for each section, with the idea that on the first page there would be a first form, then you hit 'Continue to next section' which essentially is the 'submit' button, which moves the user to section two, etc, until they hit the last section. i am not actually storing the results of the form in a database, but rather sending an email. the idea then is to store the separate form answers (one html form per section in the real form) as arrays or objects in the session, so that if they go back to a section in the form, it repopulates the values they entered since they are stored in the session. the result would be an array in the session storing the results for each of my forms, and i have one form for each section.

my question is: is it secure to temporarily store things like SSNs or driver's license numbers as session variables? why or why not?