Pizza restaurant owners in America have been bombarded with letters threatening them with bad online publicity including bad reviews on sites such as Yelp, as well as physical damage such as food contamination -- and demanding payment in Bitcoin, according to a report by veteran security blogger Brian Krebs.

Bitcoin extortion – bad reviews, fake pizza orders, and worse...

Local news stations such as Michigan’s Wood TV reported the arrival of Bitcoin extortion letters headed, Notice of Extortion, and threatening “irreparable harm” from threats such as bad online reviews and fake pizza orders, to more sinister physical attacks such as bomb threats and “contamination”.

In all, at least 16 establishments received the Bitcoin extortion letters, according to an IB Times report.

Michigan restaurant owner Mike Raymond said to Wood TV, “There’s food costs and finance and labor and rising cost of gas. All those things. Do  you really need to have somebody now threatening you with extortion?”

The Register said that the letters demanded payment of one Bitcoin, with an additional threat that if payment was not received the fee would rise to three Bitcoins. At the time of writing, the exchange rate for one Bitcoin was $618, according to Bitcoin converter Preev.

Speaking to Krebs, UC Berkeley researcher Nicholas Weaver said, "This type of attack could be fairly effective. Some businesses — particularly restaurant establishments — are very concerned about negative publicity and reviews. Bad Yelp reviews, tip-offs to the health inspector, that stuff works and isn’t hard to do.”

"The gloves come off"

Weaver added “There is a lot of operational security that these guys might have failed at because this is interstate commerce, mail fraud, and postal inspector territory – where the gloves come off. I’m willing to bet there are several tools available to law enforcement here that these extortionists didn’t consider.”

The Register reports that a Reddit thread discussing the Bitcoin extortion threats suggested that the culprits might be traced by print stenography, which allows law enforcement officials to trace the make and model of printers used to create documents.
The digital wallets linked to the Notice of Extortion letters did not appear to have had money transferred to them, The Register reported.