What’s the key to the perfect pump-and-dump Ponzi scheme? Plausibility and prey.

Meet the new wolf of Wall Street: bitcoin, the anonymous computer “Tinkertoy crypto-currency,” as we dubbed it in a year-end column.

And now the crypto-currency has toppled, with bitcoin values cut in half in the last week, if you can even get your “money” back.

Ponzi-type scams have been around since the 1920s. The greed and dishonesty never change; the techniques just keep evolving. Wolves like to eat.

For sure, they are harder to spot these days than the one in Martin Scorsese’s Oscar-nominated film “The Wolf of Wall Street.”

Long gone are the silk-suited in-your-face wise guys, waving bottles of Dom Perignon around and snorting coke off the bodies of prostitutes at parties.

Today’s wolves are much greedier and much more sophisticated. They are faceless, anonymous cyber-criminals. Bitcoin was their tool, their penny stock, their empty shell company. In the fall of 2011, bitcoin was at $2. By November 2013 it had risen to more than $1,000!

If that’s a currency, those bitcoinians must be some productive citizens.

Today it stands at $350. All is not well: Bitcoin, the anarchist currency used by drug dealers and other illicit sorts, has fallen into, um, bits and pieces.

I truly feel bad for the innocent people who got conned into investing in the bitcoin shell game, but fortunately there really were not that many widows and orphans who got taken here. Mostly it was some of the people who thought they were “the smartest guys in the room.”

Today, many of the largest bitcoin exchanges located around the world claim they have been under “cyberattack” and have halted redemptions, including Japan’s Mt Gox, the third-largest “exchange.”

As a digital delivery system, perhaps bitcoin can be saved. But a currency built by hackers and anonymous code-writing anarchists offers a pretty weak alternative to cash, credit cards or PayPal.

But if you saw the movie, you know that “wolves” lure the unwary in, let them feed and grow comfortable for a while — and then the wolves pounce.

Welcome to the 21st-century Ponzi scheme.