Bitcoin is virtual cash that can be used among friends or between customers and merchants – anywhere ordinary money is spent or exchanged. It exists as digital information rather than physical money: Each bitcoin is a string of mathematically generated numbers. This sequence can be printed on a piece of paper or embedded in a coin, as a physical reminder, but it is the number, not the object (as in other currency), that has value.

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Bitcoin tokens are gathered in Sandy, Utah, in April.