Authorities with high computer capacity able to destroy Bitcoin?

[maeusi]

Not enough that banks and governments have begun a fight against Bitcoin. Now I read a worrying analysis in a local business magazine (Handelsblatt.com).
Thus (I express strongly curtailed and simplified) intelligence agencies or other institutions could obtain the 51% majority of the blockchain and manipulate it with own version (?). That would be made possible by the merger of a hash power over 15,000,000,000 GH/s, which could be realized with $ 3 billion plus electricity costs. I am not a technician. So I'll ask here, if it's just nonsense or indeed the Archilles heel of Bitcoin and most other cryptocurrencies.
Source: Handelsblatt
https://www.google.de/amp/amp.handelsblatt.com/finanzen/rohstoffe-devisen/coin-und-co-die-krypto-kolumne-so-koennten-geheimdienste-den-bitcoin-zerstoeren/20922818.html

[BelieveInBitcoin]

I think it's missing the point. Yes spending $3b might get you control of one currency - so everyone moves their money to another one. There are thousands of them. That's kind of the point, no-one can ever dominate all crypto even if in theory it's possible to dominate one.

[maeusi]

I think it's missing the point. Yes spending $3b might get you control of one currency - so everyone moves their money to another one. There are thousands of them. That's kind of the point, no-one can ever dominate all crypto even if in theory it's possible to dominate one.

The question is: Is it technically possible, that the blockchain can be manipulated under certain circumstanes like discribed in first post? If yes, why isn't it done yet? 3$ b is not much for those institutions. If not, how is the blockchain protected against an attack on that dimension?

[Sumo]

Understand!) The fact is that this news, like many other negative news, is coming out now, when all the crypto-currency market is falling. Thus, such news contributes to the market movement, so that large and experienced investors come at more favorable prices. Do not believe everything that the media write.

[Cashew]

Any authority in the world could not get the hand on so much ASICs so easily. They would have to develop their own one, and at the end, it will be more profitable to sell it than to destroy Bitcoin with it. It is the corrupted policeman which at the end covers the drug market because it rewards better.

[swogerino]

I think it's missing the point. Yes spending $3b might get you control of one currency - so everyone moves their money to another one. There are thousands of them. That's kind of the point, no-one can ever dominate all crypto even if in theory it's possible to dominate one.

Yes it is possible although it does not make any sense as people can migrate to Ether. A 51% attack means that a group of people in this case governments can control more than 50% of the network and are able to make transactions not valid if they decide to. Of course transactions that are made after they have taken control of the network. Also when this group is in control it can double spend the coins from transactions that were made when they are in control. This remains only hypothetical so far and I doubt we will ever see this attack in action.

[maeusi]

I think it's missing the point. Yes spending $3b might get you control of one currency - so everyone moves their money to another one. There are thousands of them. That's kind of the point, no-one can ever dominate all crypto even if in theory it's possible to dominate one.

Yes it is possible although it does not make any sense as people can migrate to Ether. A 51% attack means that a group of people in this case governments can control more than 50% of the network and are able to make transactions not valid if they decide to. Of course transactions that are made after they have taken control of the network. Also when this group is in control it can double spend the coins from transactions that were made when they are in control. This remains only hypothetical so far and I doubt we will ever see this attack in action.

It would make no sense from an economic point of view, you're completely right. But it would have a huge psychological effect, that would affect all cryptocurrencies.

[Rotsor]

No authority can destroy bitcoin even if they have a very high computer capacity.