Is a quantum computer dangerous for Bitcoin?
Many researches say that in less than 10 years сomputing machines using quantum principles will threaten blockchain technology which is a basis for cryptocurrencies.
Bitcoin and similar systems’ defense algorithm is based on a principle of asymmetric encryption with and open and private keys. Transaction is signed by a private key, and its truth is checked with a help of an open key.
Despite the fact that Bitcoin blockchain uses asymmetric encryption, the users don’t have to worry for the safety of their coins. The open key is not stored openly. Thus, the addresses for coins transferring are not open keys, but just the results of usage of hash-function SHA-256. The hashing function performs one-sided transformation and that’s why it’s stable against quantum computer attacks.
The public key is rendered to the network in the open way just until it receives a confirmation. If an attacker receives an open key during transaction, he will have around 10 minutes to get the private key with the help of a quantum computer and try to make his own transaction from the same address but specifying a larger commission.
By the way, bitcoin mining is also relevantly safe, as the equipment for mining cryptocurrencies in the near future will be more powerful that quantum computers.
It is worth to note, that quantum calculations threaten absolutely all systems of computer security which care based on cryptography with an open key, and not only blockchain. Internet connections to render your password in Internet banking uses a similar encryption technology, same as communication in chatrooms, social networks and lots of other routine actions.
All security systems, including blockchain systems, need to take into account postquantum encryption to ensure data safety. But the most simple and effective way can be changing traditional systems by such blockchain which implements quantum-resistant cryptography.
There are several different ways of encryption with open key resistant to quantum calculations: bases on matrix, on code, multidimensional quadratic functions, and hashing function. But let us not digress into detail math stories.
The main point is that if there is a serious threat to blockchain posed by quantum computer, developers can improve the protection. Moreover, successful research and developments in this regards are being done not for the first year.
What do you think, who will be the first in this race – bitcoin developers or quantum computer developers?