Norwegians should ensure they have a variety of payment options—including cash—so they are prepared for the possibility of a cyberattack, says Norges Bank.

A report recently published by Norway’s Central Bank on financial infrastructure and payment systems warns the nation’s payments need to be made more resistant to outages, with a focus on deliberate attacks aiming to destabilise the country.

Recognising the resilience of cash—which can be used without electricity or an internet connection—the report highlights the importance of keeping a store of banknotes on hand. The exact amount needed, it says, will ‘depend on the size of the household, and its particular necessities’. Citizens are also advised to hold several payment cards and split their money between different banks.