/// <summary>
/// Export the public RSA keyinfo from the current crypto provider
/// </summary>
/// <param name="hProv">Handle to the crypto provider</param>
/// <param name="signature">Set to true for AT_SIGNATURE, false for AT_KEYEXCHANGE</param>
/// <returns>An IntPtr pointing to the public key info structure</returns>
private IntPtr ExportPublicKeyInfo(CryptoApiMethods.SafeCryptProviderHandle hProv, bool signature)
{
CryptoApiMethods.CALG type = signature ? CryptoApiMethods.CALG.AT_SIGNATURE : CryptoApiMethods.CALG.AT_KEYEXCHANGE;
IntPtr ret = IntPtr.Zero;
uint infoLen = 0;
if (!CryptoApiMethods.CryptExportPublicKeyInfoEx(hProv, type, CryptoApiMethods.CertEncoding.X509_ASN_ENCODING,
CryptoApiMethods.szOID_RSA_RSA, 0, IntPtr.Zero, ret, ref infoLen))
{
throw new Win32Exception(Marshal.GetLastWin32Error());
}
ret = Marshal.AllocHGlobal((int)infoLen);
if (!CryptoApiMethods.CryptExportPublicKeyInfoEx(hProv, type, CryptoApiMethods.CertEncoding.X509_ASN_ENCODING,
CryptoApiMethods.szOID_RSA_RSA, 0, IntPtr.Zero, ret, ref infoLen))
{
throw new Win32Exception(Marshal.GetLastWin32Error());
}
return(ret);
}
