public KeyUsage GetKeyUsage(X509Certificate2 cert)
{
if (cert == null || cert.Handle == IntPtr.Zero)
{
throw new ArgumentNullException(nameof(cert));
}
if (cert.Extensions == null)
{
return(KeyUsage.None);
}
KeyUsage keyUsage = KeyUsage.None;
foreach (var extension in cert.Extensions)
{
X509EnhancedKeyUsageExtension ekus = extension as X509EnhancedKeyUsageExtension;
if (ekus != null)
{
foreach (var eku in ekus.EnhancedKeyUsages)
{
if (EnhancedKeyUsage.ContainsKey(eku.Value))
{
keyUsage = SetFlag(keyUsage, EnhancedKeyUsage[eku.Value]);
}
}
}
ekus = null;
X509BasicConstraintsExtension basicConstraintsExtension = extension as X509BasicConstraintsExtension;
if (basicConstraintsExtension != null)
{
if (basicConstraintsExtension.CertificateAuthority == true)
{
keyUsage = SetFlag(keyUsage, KeyUsage.CertificateAuthority);
}
}
basicConstraintsExtension = null;
}
return(keyUsage);
}
