Using FindPrivateKey in WebApi - asp.net-web-api

Question

I downloaded the source code for FindPrivateKey.exe.
I use this exe to find the filename and folder for a private key. I have to run this locally on the machine. I am looking for a way to get this information remotely using web api.
FindPrivateKey.exe works by itself as a console app.
But in my webapi code, it does not work (CryptAcquireCertificatePrivateKey returns false)
Is there an obvious reason for this? The web api site has AllowAnonymousAccess enabled, is that why?
I'm having trouble including the code snippet. Summarizing:
StoreName is "My"
StoreLocation is "Local Machine"
//the call below returns false and this is where I am stuck
if (CryptAcquireCertificatePrivateKey(cert.Handle,
acquireFlags, IntPtr.Zero, ref hProvider, ref _keyNumber, ref freeProvider))
{
...
}

Answer 1

I was able to get this to work by first impersonating a user with rights to the private key information. For anyone interested, google the DllImport code below for how to do this.
[DllImport("advapi32.dll", CharSet = CharSet.Auto)]
public static extern int LogonUser(
string lpszUserName,
String lpszDomain,
String lpszPassword,
int dwLogonType,
int dwLogonProvider,
ref IntPtr phToken);
[DllImport("advapi32.dll", CharSet = System.Runtime.InteropServices.CharSet.Auto, SetLastError = true)]
public extern static int DuplicateToken(
IntPtr hToken,
int impersonationLevel,
ref IntPtr hNewToken);