/// <summary> /// Extract issuer alternative name is available. /// </summary> /// <returns>Issuer alternative name or null.</returns> protected GeneralNames GetIssuerAlternativeName() { Asn1OctetString extensionValue = Issuer?.GetExtensionValue(new DerObjectIdentifier(X509Extensions.SubjectAlternativeName.Id)); return(extensionValue == null ? null : GeneralNames.GetInstance(X509ExtensionUtilities.FromExtensionValue(extensionValue))); }