Issue: Getting 'This implementation is not part of the Windows Platform FIPS validated cryptographic algorithms.' exception while building Outlook VSTO add-in in VS 2010

In case you have FIPS compliance enabled and you are building VSTO/Windows applications using Visual Studio 2010 then you will get exception as mentioned below:

Error 1 Source file 'c:\users\brijs\documents\visual studio 2010\Projects\OutlookAddInFIPS\OutlookAddInFPIS\ThisAddIn.cs' could not be opened ('This implementation is not part of the Windows Platform FIPS validated cryptographic algorithms.') OutlookAddInFIPS

Error 1 Source file 'c:\users\brijs\documents\visual studio 2010\Projects\WindowsFormsApplicationFIPS\WindowsFormsApplicationFIPS\Form1.cs' could not be opened ('This implementation is not part of the Windows Platform FIPS validated cryptographic algorithms.') WindowsFormsApplicationFIPS

To know more about FIPS refer The effects of enabling the "System cryptography: Use FIPS compliant algorithms for encryption, hashing, and signing" security setting in Windows XP and in later versions of Windows

In order to enable FIPS you need to follow steps mentioned below

• This security setting affects the following registry value in Windows Server 2008 and in Windows Vista: HKLM\System\CurrentControlSet\Control\Lsa\FIPSAlgorithmPolicy\Enabled
  This registry value reflects the current FIPS setting. If this setting is enabled, the value is 1. If this setting is disabled, the value is 0.
  
• This security setting affects the following registry value in Windows Server 2003 and in Windows XP: HKLM\System\CurrentControlSet\Control\Lsa\FIPSAlgorithmPolicy
  This registry value reflects the current FIPS setting. If this setting is enabled, the value is 1. If this setting is disabled, the value is 0.

After you enable or disable the System cryptography: Use FIPS compliant algorithms for encryption, hashing, and signing security setting, you must restart your application, such as Internet Explorer, for the new setting to take effect.

To workaround the above issue you can either opt out of FIPS compliance by changing the registry as mentioned above.

Or In order to just avoid the issue with Visual Studio 2010 one can follow the steps mentioned below:

• Open Devenv.exe.config from
  C:\Program Files (x86)\Microsoft Visual Studio 10.0\Common7\IDE if you are on x64 OS
  or C:\Program Files\Microsoft Visual Studio 10.0\Common7\IDE\ on x86 OS
  
• Find </runtime> tag and add the following above that line:
  <enforceFIPSPolicy enabled="false"/>
  
• After the above modification devenv config would look like:
  <configuration>
  <runtime>
  .
  .
  .
  <enforceFIPSPolicy enabled="false"/>
  </runtime>
  </configuration>
  
• Restart Visual Studio

enforceFIPSPolicy is a .Net 2.0 SP1 config file switch which helps the application to opt out FIPS checking.

Hope this helps!!!