"There are some problems involved with implementing unforgeable costliness on a computer. If such problems can be overcome, we can achieve bit gold.
"This would be the first online currency based on highly distributed trust and unforgeable costliness rather than trust in a single entity and traditional accounting controls.
"Hal Finney has implemented a variant of bit gold based on a tamper-evident computer plug-in card, for which remote users can verify what code is running on the card."
- Nick Szabo, August 2008.