Police in Calgary, Winnipeg, Toronto, Hamilton, Halton and other Canadian centres after hunting for four men seen above who stole almost $200,000 by employing a trick known as a double spending attack.
According to the police profiling, one of the suspects has attacked in the Toronto, Montreal, Ottawa and Hamilton area, while the other took the Calgary area for the attacks.
The suspects had "in-depth knowledge or interest in cryptocurrency, Bitcoin and/or blockchain technology", Calgary police said. Calgary police say they began investigating the matter in October 2018 after receiving a tip-off.
Between Sept. 16 and 26, four men were captured on CCTV cameras making 112 withdrawals from Bitcoin kiosks in seven Canadian cities.
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Todd is among the Bitcoin developers who developed a tool that allows processing transactions lost in the process, however, a tweaked version of the same is believed to be used for these scam transactions.
Bitcoin scheme suspect number one. The cities which fell victim to the attack include Calgary, Toronto, Montreal, Winnipeg, Sherwood Park, Ottawa and Hamilton. While not designed for criminal applications, the tool is described by Todd as a means of creating successive transactions to smooth "stuck" transactions.
Some miners won't accept transactions with these output types; those miners will accept the second double-spend transaction, helping you achieve a successful double-spend.
The double spends, which occurred over the course of 10 days, are possible with unconfirmed transactions and tools exist to deal with this problem.
Police from Toronto, Hamilton, Halton and Winnipeg are assisting with the Calgary Police Cybercrime Division's investigation of the thefts. People can also anonymously submit tips through Crime Stoppers.