I installed Microsoft Visual Studio 2013 a while back then uninstalled it because I needed space and a few months later when I tried to reinstall I got this error for SQL database tools and the other SQL packages that come with Visual Studio 2013, error is "the timestamp signature and/or certificate could not be verified or is malformed".
i finally found a solution to my problem. The error is caused be an SHA256 ceritificate thats in the build and the certificate expires on 10/6/2013 therefore when installing Visual Studio 2013 in present day it presents that error. The work around i used was to set the clock on my laptop before that date and then install Visual studio 2013 and the workaround was successful. Credit does not go to me, i only obtain this information from the following web page:
credit goes to Jill McClenahan the individual that posted the solution. Forgive me explaination i am a newbie.