Burger King just posted the biggest sales gain in 2 years. Reuters Fast-food chain Burger King has launched its own "cryptocurrency" in Russia called "WhopperCoin".

Burger King customers in Russia can earn one WhopperCoin for every rouble (0.01p) they spend on the Whopper sandwich, according to a press release issued last Friday by partner organisation Waves.

Russian customers can then redeem a Whopper burger when they have collected 1,700 WhopperCoins. Like other blockchain tokens, WhopperCoin can also be freely transferred and traded online.

WhopperCoin was described as being little more than a glorified loyalty points program by The Financial Times on Tuesday.

Burger King Russia plans to release iOS and Android apps in the next month that will allow customers to sell their WhopperCoins and send them to friends.

Ivan Shestov, head of external communications at Burger King Russia, said in a statement: "Eating Whoppers now is a strategy for financial prosperity tomorrow."

Shestov added: "Now Whopper is not only [a] burger that people in 90 different countries love — it's an investment tool as well. According to the forecasts, cryptocurrency will increase exponentially in value."

Burger King Russia is using a digital currency platform built by Waves for the WhopperCoin.

"We are glad that Burger King Russia has chosen Waves as a platform for its loyalty program launch and WhopperCoin distribution," said Max Pertsovskiy, chief business development officer of Waves Platform, in a statement. "We are sure that this decision will promote blockchain technology in Russia and will enable the promotion of its benefits and possibilities for a wide audience."