Common default values
sanity check, prevent doing ridiculous PoW 20 million PoWs equals approximately 2 days on dev’s dual R9 290
Remember here the RPC port read from namecoin.conf so we can restore to it as default whenever the user changes the “method” selection for namecoin integration to “namecoind”.
The amount of work that should be performed (and demanded) per byte of the payload.
To make sending short messages a little more difficult, this value is added to the payload length for use in calculating the proof of work target.