usesDefaultMac method
Init logon (0800/0810 with processing code 920000 or 920001) is MACed with the key derived from the KTM; everything else uses the session MAC key.
Implementation
bool usesDefaultMac(IsoMsg message) {
final String? mti = message.hasField(0) ? message.mti : null;
if (mti != "0800" && mti != "0810") return false;
final String? processingCode = message.getString(3);
return processingCode == "920000" || processingCode == "920001";
}