I used an example of CNG provider from CSPDK to implement my own CNG Hash Provider. But as appeared when I use PKCS7 (Signed Message) WinApi functions CNG provider doesn't work. CryptMsgOpenToEncode function reports 0xC0000005 error, which appears also when there is no provider at all. Under admin account everything works fine. If I use MicroSoft example of CNG Hash Provider directly it reports same error. Also if I try to install provider under user account without admin permissions I get 0xC0000022 error from BCryptRegisterProvider function. Also the provider doesn't work if UAC (User Access Control) is enabled.
What is the correct way to install CNG provider (it could be done under admin) in order to make it work under user account?