[Cryptography] algorithm for offline spend?

[jamesd at echeque.com]

Some time ago, someone constructed an algorithm for offline on the spot
spending of a coin.

Assume all participants have a valuable secret key that they do not want
to reveal.

Every time you spend the coin to someone else, it accumulates more data
(and must eventually spent online to strip off the excess data.

If anyone double spends the coin, he reveals his secret key.

Does anyone recollect a link or cite for that algorithm?

That algorithm might make it possible to fix the lightning network
to work as it should.