North Korea was blamed by the United States for the WannaCry hack earlier this year which demanded money in bitcoin.
An expert has claimed that bitcoin, which has seen a huge recent surge in value, is the perfect currency for North Korea.
Speaking to CNBC, CrowdStrike CEO George Kurtz said he believed North Korea is appreciating the increase in bitcoin price.
He said: “This is significant because the US Government does not take these attribution cases lightly.
“We have been tracking this early on, we certainly agree with the US Government but I think it highlights the capabilities that North Korea has in cyber.
“What we have seen is that the increase in capabilities in the last three years and it is something that a lot of countries should be concerned about, particularly those companies that are dealing with bitcoin and cryptocurrencies.”
Mr Kurtz added that he believed the rogue state to be “building a cache of bitcoin”.
He said: “It’s an anonymous currency, it can easily bypass any sort of sanctions because there are none on bitcoin, and the value has increased dramatically.
“It is the perfect currency for North Korea to be hoarding.”
Bitcoin peaked at £14,251.01 ($19,026.21) on Monday, according to the CoinDesk exchange before slumping down to £13,221.59 ($17,651.85). On Sunday, Bitcoin hit a new record high price as the cryptocurrency board past $20,000.
Fears have been raised that the currency could “spiral out of control” after warnings from experts.
Oliver Isaacs, Cryptocurrency investor, believes the cash coin bubble will eventually burst with massive consequences for investors.
He said: “Personally I think Bitcoin will be the biggest bubble of our lifetime. Bitcoin has already reached over $10,000 a coin and it will not be long until bitcoin valuations and prices continue to rise and spiral out of control.”
The United States said North Korea was behind the WannaCry cyber attack and the White House’s Homeland Security advisor Thomas Bossert said: “The US today publicly attributes the massive ‘WannaCry’ cyberattack to North Korea.
“We do not make this allegation lightly. It is based on evidence. The attack spread indiscriminately across the world in May. It encrypted and rendered useless hundreds of thousands of computers in hospitals, schools, businesses and homes.
“While victims received ransom demands, paying did not unlock their computers. It was cowardly, costly and careless. The attack was widespread and cost billions, and North Korea is directly responsible.
“Other governments and private companies agree. The United Kingdom attributes the attack to North Korea, and Microsoft traced the attack to cyber affiliates of the North Korean government.”
The WannaCry cyber attack targeted 150 countries and sent many of the UK’s NHS hospitals into meltdown.
Wanna Decryptor, also known as WannaCry or wcry, was the ransomware programme used in the attack, used by hackers to block access to a computer system until a ransom is paid.