A five-month long investigating
The debate around RBF
CBC News reports that four scammers successfully conducted double spend attacks, targeting Bitcoin ATMs in Canada’s major cities. The police are currently working on identifying the four suspects who stole $200,000.

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A five-month long investigating
Almost half of the attacks, which were conducted over a span of ten days in September 2018, took place in the city of Calgary. Calgary police started investigating the crime back in October after getting a tip-off about the defrauded Bitcoin ATM company. Notably, every suspect would operate in a separate city.

The photos of the bad actors have been posted online, and the police are asking the public to assists the investigators in identifying them. You can anonymously provide pertinent information to the police.

The debate around RBF
The news has already sparked a debate about Bitcoin’s replace-by-fee (RBF) that allows users to re-send unconfirmed transactions by paying a higher fee. This feature is very controversial since many believe that it could lead to double-spending attacks. While double-spending is possible without RBF, the feature makes it a lot of easier even for non-tech folks to pull off such a scam.

These guys double spent BTC at ATMs using Replace by Fee. Stole over $200,000 over 112 transactions.

Bitcoin ATM Double-Spenders: Police Need Help Identifying Four Criminals
CBC reports that four Canadian men are wanted in connection with conducting double-spend attacks against Bitcoin ATMs in four cities. A total of 112 transactions are alleged to have taken place in…

RBF is a bad design idea, it literally invites this behavior. Another bad idea is the 1MB transaction limit, they could do the same if the blocks ever become congested again.

By Alex Morris