I have a solution with more than one ASP.NET web-application. Every application has its own virtual directory on the same IIS. One application is calling aspx pages in the other applications. How can I share some information (e.g. user/password) between these applications. Is the only way using querystrings (in this case, I must encrypt the information). Or are there other possibilities / techniques ?
maybe this will help you: http://forums.asp.net/p/1411879/3097085.aspx
Maybe this will help, I asked and answered this question myself
Using one Asp.net Membership database with multiple applications
I had two asp.net applications on one IIS server. It was my goal to make it so when user logged onto app1 their user credentials would be available in app2. Configuring the asp.net membership provider is only one step of what I was looking for. Even if both apps were using the same back end database and provider I still wouldn't be authenticated when I hit app2. What I was looking for was a Single Sign On solution.
Once you have both apps pointing at your asp_membership database by placing the following in the system.web section of your web config
make sure both have the same applicationname property set.
I was using IIS 6 so I configured it to autogenerate a machine key for both applications. Because both of these applications live on the same machine the key would be identical, this is the critical part to making the SSO work. After setting up IIS the following was added to my web.config
<machineKey decryptionKey="AutoGenerate" validation="SHA1" validationKey="AutoGenerate" />
That was all there was to it. Once that was done I could log into app1 and then browse to app2 and keep my security credentials.
Thanks for the push in the right direction.