/// <summary>
/// Read a parameter using VERIFY_CONTEXT to read from the device being targeted by _parameters
/// </summary>
private object ReadDeviceParameterVerifyContext(CapiHelper.ClrPropertyId keyParam)
{
CspParameters parameters = new CspParameters(_parameters);
// We're asking questions of the device container, the only flag that makes sense is Machine vs User.
parameters.Flags &= CspProviderFlags.UseMachineKeyStore;
// In order to ask about the device, instead of a key, we need to ensure that no key is named.
parameters.KeyContainerName = null;
const uint OpenDeviceFlags = (uint)Interop.Advapi32.CryptAcquireContextFlags.CRYPT_VERIFYCONTEXT;
SafeProvHandle safeProvHandle;
int hr = CapiHelper.OpenCSP(parameters, OpenDeviceFlags, out safeProvHandle);
using (safeProvHandle)
{
if (hr != CapiHelper.S_OK)
{
throw new CryptographicException(SR.Cryptography_CSP_NotFound);
}
object retVal = CapiHelper.GetProviderParameter(safeProvHandle, parameters.KeyNumber, keyParam);
return(retVal);
}
}
/// <summary>
/// Read a parameter from the current key using CRYPT_SILENT, to avoid any potential UI prompts.
/// </summary>
private object?ReadKeyParameterSilent(CapiHelper.ClrPropertyId keyParam, bool throwOnNotFound = true)
{
const uint SilentFlags = (uint)Interop.Advapi32.CryptAcquireContextFlags.CRYPT_SILENT;
SafeProvHandle safeProvHandle;
int hr = CapiHelper.OpenCSP(_parameters, SilentFlags, out safeProvHandle);
using (safeProvHandle)
{
if (hr != CapiHelper.S_OK)
{
if (throwOnNotFound)
{
throw new CryptographicException(SR.Cryptography_CSP_NotFound);
}
return(null);
}
object retVal = CapiHelper.GetProviderParameter(safeProvHandle, _parameters.KeyNumber, keyParam);
return(retVal);
}
}