McKinsey on blockchain treat: “potential security challenge arises from advances in quantum computing. Google said in 2016 its quantum prototype was 10 million times faster than any computer in its lab. That raises the possibility that quantum computers will be able to hack codes used to authorize cryptocurrency transactions” https://bit.ly/2FvvAC5

SEC and other government agencies (NSA plans using quantum computers to break hard targets) preparing to analyze publicly available blockchains and willing to attribute addresses with owners data. Check recent sources sought announcement on fbo.gov by SEC here https://www.fbo.gov/index?s=opportunity&mode=form&id=c18a03f93cf06df47dab8a1c1a7f87a9&tab=core&_cview=0

So all currencies (like Bitcoin, Monero, Grin etc) not using post-quantum cryptography are vulnerable and going to be cracked by governments in like 10 years - all current data going to be still in public blockchains and most of crypto-enthusiasts alive to face governments charges.

Once it becomes a reality, a general quantum computer with long coherence times will easily be able to defeat today’s encryption schemes, for example. That’s not what today’s announcement is about, but it is surely something that all of the world’s governments are thinking about.

How UK government wants to track your crypto transactions https://www.theblockcrypto.com/post/53473/uks-tax-authority-wants-to-deploy-a-blockchain-analytics-tool-to-catch-crypto-cybercriminals

The world’s first commercially available 5-qubit QPU.