static Wincrypt.CRYPT_ATTRIBUTE create_attribute(IntPtr handle, UInt32 propId)
{
UInt32 pcbData = 0;
Wincrypt.CRYPT_ATTRIBUTE attrib = new Wincrypt.CRYPT_ATTRIBUTE();
if (Crypt32.CertGetCertificateContextProperty(handle, propId, IntPtr.Zero, ref pcbData))
{
attrib.rgValue = Marshal.AllocHGlobal((Int32)pcbData);
attrib.pszObjId = "1.3.6.1.4.1.311.10.11." + propId;
attrib.cValue = pcbData;
Crypt32.CertGetCertificateContextProperty(handle, propId, attrib.rgValue, ref pcbData);
}
else
{
throw new Win32Exception(Marshal.GetLastWin32Error());
}
return(attrib);
}
/// <summary>
/// Gets a specified certificate context property.
/// </summary>
/// <param name="cert">Certificate.</param>
/// <param name="propID">Property ID to retrieve.</param>
/// <exception cref="ArgumentNullException">
/// <strong>cert</strong> parameter is null reference.
/// </exception>
/// <exception cref="UninitializedObjectException">
/// Certificate object is not initialized and is empty.
/// </exception>
/// <exception cref="Exception">
/// Requested context property is not found for the current certificate object.
/// </exception>
/// <returns>Specified certificate context property.</returns>
public static X509CertificateContextProperty GetCertificateContextProperty(this X509Certificate2 cert, X509CertificatePropertyType propID)
{
if (cert == null)
{
throw new ArgumentNullException(nameof(cert));
}
if (IntPtr.Zero.Equals(cert.Handle))
{
throw new UninitializedObjectException();
}
UInt32 pcbData = 0;
switch (propID)
{
case X509CertificatePropertyType.Handle:
case X509CertificatePropertyType.KeyContext:
case X509CertificatePropertyType.ProviderInfo:
if (!Crypt32.CertGetCertificateContextProperty(cert.Handle, propID, IntPtr.Zero, ref pcbData))
{
throw new Exception("No such property.");
}
IntPtr ptr = Marshal.AllocHGlobal((Int32)pcbData);
Crypt32.CertGetCertificateContextProperty(cert.Handle, propID, ptr, ref pcbData);
try {
return(new X509CertificateContextProperty(cert, propID, ptr));
} finally {
Marshal.FreeHGlobal(ptr);
}
// byte[]
default:
if (!Crypt32.CertGetCertificateContextProperty(cert.Handle, propID, null, ref pcbData))
{
throw new Exception("No such property.");
}
Byte[] bytes = new Byte[pcbData];
Crypt32.CertGetCertificateContextProperty(cert.Handle, propID, bytes, ref pcbData);
return(new X509CertificateContextProperty(cert, propID, bytes));
}
}
