A more exact error is “An exception oftype System.Security.Crypthography.CryptographicException” and happened when I was trying to install SharePoint2010 on windows 7 x64

I tried to find a solution and fixed the problem by

1. give full control for NETWORK SERVICE system user to the folder:
C:\Program Files\Common Files\Microsoft Shared\Web Server Extensions\14
(right click->security->add)

2. delete the registry key: HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Shared Tools\Web Server Extensions\14.0\Secure\FarmAdmin