We have all heard of quantum computing, and some know more than others what it is. In short, quantum computing uses quantum bits and quibits to encode information, as opposed to the basic 1 and 0 in regular computers. This allows them to be in both a 1, and 0 state at the same time. Basically, quantum computing can compute operations at much higher speeds than a normal computer. But, I am not here to talk about quantum computing, I am here to talk about its affect on cryptocurrencies, and main its affect on Bitcoin.

Bitcoin uses the combined power of the miners to secure the currency. Therefore, the only way to directly attack Bitcoin would either be to target the nodes or launch an attack on Bitcoin. An attack on bitcoin would most likely fail, as one would need more power than at least half of the miners(a majority) Currently, bitcoin has a large amount of miners and would be difficult to attack directly. A second way to attack bitcoin would be through targeting the nodes via viruses and such. There would really be no way that Quantum computing could help in this regard. Also, as any viruses you put in a bitcoin transaction will not go through a nodes computer, therefore not affecting them.

So, how will quantum computers affect bitcoin? To answer this we need to talk about how a public and private key are encrypted. The public key is used for encryption, but your private key is used for decryption. Essentially, a private key would give you access to a users bitcoin. This is where quantum computing comes in, as quantum computing can compute with extreme speeds, it can get the private key if it obtained a public key, with modern computers this would take the age of the universe. Thankfully, modern quantum computers can not do this yet, it will be another 20-40 years until a Quantum computer would have enough computational power to do this.

How would they get your public key first though? Well, your public key is similar to a signature, you sign it on every transaction, therefore, if they were able to gain access to your signature(public key), which is possible, a quantum computer could decrypt your private key.

Luckily, all of this could only happen a good amount in the future, but as we have learned in the past, it would be hard to change this in bitcoin without a hard fork. In the end, quantum computing has many advantages, but could pose some problems not just for crypto, but for all encryption methods.