I have done the custom form authentication for SharePoint 2013. For web.config change, I need the publickKeyToken. Initially I struggled to get the public key token from my dll. Then I find the solution for this.
Here we will see that how to get the key.
1. In start menu, open “Developer Command Prompt for VS2012”
2. In command prompt type “sn –T” and drag and drop the dll like below
Note: use –T instead of –t (because case sensitive)