Setting PIN prompt in Smart Card Crypto Provider's dialog box

Question

I want to change the text that shows when invoking CryptoApi operation that requires smart card PIN. Current prompt is pretty generic (and in system's language), "Please enter your authentication PIN":

This dialog shows when calling CryptSignMessage in COM object, but the call is made from C# WPF desktop app (.NET 4.5). How can I customize the dialog? I've found PP_PIN_PROMPT_STRING parameter for CryptSetProvParam function, but the function requires HCRYPTPROV and I don't have that handle. All I have is reader's name and signing certificate. Just can't wrap my head around it.

Is it possible to customize PIN dialog from either C++ or C# (preferably C#)?

Answer 1

I believe the following should work. As I don't have anything setup to test collecting the information I can't verify.

[DllImport("advapi32.dll", SetLastError = true, CharSet = CharSet.Auto)]
[return: MarshalAs(UnmanagedType.Bool)]
public static extern bool CryptAcquireContext(out IntPtr phProv, string pszContainer, string pszProvider, uint dwProvType, uint dwFlags);
        
[DllImport("advapi32.dll", SetLastError = true, CharSet = CharSet.Auto)]
[return: MarshalAs(UnmanagedType.Bool)]
static extern bool CryptSetProvParam(IntPtr hProv, uint dwParam, [In] byte[] pbData, uint dwFlags);

[DllImport("advapi32.dll")]
[return: MarshalAs(UnmanagedType.Bool)]
public static extern bool CryptReleaseContext(IntPtr hProv, uint dwFlags);
        
const string MS_DEF_PROV = "Microsoft Base Cryptographic Provider v1.0";
const uint NTE_BAD_KEYSET = 0x80090016;
const uint PROV_RSA_FULL = 1;
const uint CRYPT_VERIFYCONTEXT = 0xF0000000;
const uint CRYPT_NEWKEYSET = 0x00000008;
const uint PP_PIN_PROMPT_STRING = 0x2C;
        
public void SetPinText(string text)
{
    byte[] data = Encoding.UTF8.GetBytes(text);
    
    IntPtr hCryptProv = IntPtr.Zero;

    try
    {
        if (!CryptAcquireContext(out hCryptProv, null, MS_DEF_PROV, PROV_RSA_FULL, CRYPT_VERIFYCONTEXT))
        {
            if (Convert.ToUInt32(Marshal.GetLastWin32Error()) == NTE_BAD_KEYSET)
            {
                if (!CryptAcquireContext(out hCryptProv, null, null, PROV_RSA_FULL, CRYPT_NEWKEYSET))
                    throw new Exception("Unable to acquire crypt context.");
            }
            else
            {
                throw new Exception("Unable to acquire crypt context.");
            }
        }
    
        if (!CryptSetProvParam(hCryptProv, PP_PIN_PROMPT_STRING, data, 0))
            throw new Exception("Unable to set prompt string.");
    }
    finally
    {
        if (hCryptProv != IntPtr.Zero)
        {
            CryptReleaseContext(hCryptProv, 0);
        }
    }
}