Canadian police are looking for four men suspected of organizing attacks of double spending on bitcoin rooms in different cities of the country. Supposedly, in September last year they carried out 112 transactions, half of which fell on Calgary. Other attacks were carried out in the cities of Winnipeg, Toronto, Montreal, Sherwood Park, Ottawa and Hamilton. The identity of the attackers is unknown, and the Calgary police appealed to the population to assist in their establishment.
Apparently, Bitcoin accepted transactions with zero confirmation, and the attackers used this to conduct attacks of double spending Bitcoins in exchange for cash. In total, in 10 days, the fraudsters managed to complete 112 transactions and earn about $ 200,000. The average transaction amount was about $ 1,800.
It is assumed that such transactions were made possible thanks to the replace-by-fee tool developed by Canadian Bitcoin Core programmer Peter Todd (Peter Todd). Although this tool was developed for a completely different purpose, it allows you to “free” transactions by paying an additional commission. The package contains the “double spending” tool, which Todd describes as follows:
“Sequentially creates two transactions. The first sends the indicated amount to the specified address. The second performs double waste of this transaction with a transaction with a higher commission. ”
In total, Calgary has 45 bitcoinates of two leading manufacturers - Genesis Coin (the most popular) and Lamassau. The ability to sell bitcoins provides only 21 terminals. These bitcoin machines belong to different companies, including Bitnational, Bitcoin Solutions and Bitcoiniacs. Presumably, the owners of the terminals themselves set up the conditions for the implementation of transactions. Some terminals have a daily sales limit of up to $ 9,000. Whether these companies allow transactions with zero confirmation is unknown.
Apparently, Bitcoin accepted transactions with zero confirmation, and the attackers used this to conduct attacks of double spending Bitcoins in exchange for cash. In total, in 10 days, the fraudsters managed to complete 112 transactions and earn about $ 200,000. The average transaction amount was about $ 1,800.
It is assumed that such transactions were made possible thanks to the replace-by-fee tool developed by Canadian Bitcoin Core programmer Peter Todd (Peter Todd). Although this tool was developed for a completely different purpose, it allows you to “free” transactions by paying an additional commission. The package contains the “double spending” tool, which Todd describes as follows:
“Sequentially creates two transactions. The first sends the indicated amount to the specified address. The second performs double waste of this transaction with a transaction with a higher commission. ”
In total, Calgary has 45 bitcoinates of two leading manufacturers - Genesis Coin (the most popular) and Lamassau. The ability to sell bitcoins provides only 21 terminals. These bitcoin machines belong to different companies, including Bitnational, Bitcoin Solutions and Bitcoiniacs. Presumably, the owners of the terminals themselves set up the conditions for the implementation of transactions. Some terminals have a daily sales limit of up to $ 9,000. Whether these companies allow transactions with zero confirmation is unknown.