03 / 18 / 21

Can quantum computing be dangerous for cryptocurrencies


In their respective fields, both quantum computing and cryptocurrencies are doing pretty good and achieving newer milestones every quarter. However, since quantum computers are known for cracking the most difficult mathematical problems in a matter of seconds, it is the right time to ask yourself whether these powerful computers pose a threat to the crypto industry or not. 

On the internet, we can see hundreds of articles about quantum computing, and the search volume has increased particularly after Google announced its quantum supremacy a while ago where it hinted to crumble the current sophistication of cryptography, particularly the one used in Bitcoin. The question is – is it really true and how could it happen? 

In order to answer this, it is important to understand the involvement of mathematics in cryptocurrencies. Basically, these digital assets operate on the principle of “one-way function”, implying that public keys for a wallet can be generated from a private key, but not vice versa. This limitation is only because going backward would require an unimaginable amount of computational power in a very short period, which cannot be achieved on normal computers. However, since quantum computers have astronomically huge computational efficiency, it is possible for them to execute such algorithms and derive the private keys from the public ones. 

Let’s take BTC as an example to understand the threat better. Currently, a transaction on the Bitcoin network takes about 10 minutes to be finalized and if there is network congestion, this time could increase as well. The quantum computers that we currently have, take roughly 8 hours to crack the public key and trace it back to a private one. Therefore, as of today, cryptocurrencies are secure as long as the users use unique addresses every time. But whenever the quantum computers become eligible to break the RSA key in less than 10 minutes (i.e. the time taken for the BTC network to mine a transaction), the entire network would practically be broken and literally ‘exposed’. 

Therefore, according to a report published by Deloitte, more than 25% of BTCs are exposed to being affected in case of a quantum attack. So, if you feel like you have an exposed public key and the dawn of quantum computing might increase in the future, you should consider transferring your assets from your current address to a p2pkh one after taking a backup. 

It is worth noticing that the pace of quantum advancement is quite high and even if everyone takes the measure mentioned above, a crypto network might be compromised. After considering all of the cons, the only practical (but difficult) solution would be to give up the current cryptography around the digital assets and pursue a more resilient, post-quantum cryptography, that typically deals with this issue and is almost “resistant” to quantum attacks. However, this area is still being researched upon by cryptographers as their efficiency and scalability must be tested to the limits before taking any direction. 


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