User Configuration > Administrative Templates > Microsoft Office 2016 > Security Settings > Digital Signatures
User
HKCU\software\policies\microsoft\office\16.0\common\signatures
This policy setting allows you to configure the time stamping hashing algorithm used by Office 2016 applications to validate a message or document. If you enable this policy setting, you can specify any of the following standard hashing algorithm (SHA) functions: - SHA1 - SHA256 - SHA384 - SHA512 If you disable or do not configure this policy setting, SHA1 will be used.