I have read a couple of very interesting articles about the technological advance of quantum computing and its threats to cryptography. This should be of interest to all people using or investing in cryptocurrencies.
Currently, the development of quantum computers is still in an early stage but large companies like Google and also government agencies like the CIA are heavily investing in the technology. Experts say that there is a 17% chance of the singularity of a quantum computer emerging in the next 10 years. On the other hand technological advance is non linear, so theoretically the emergance of a quantum computer strong enough to pose a threat to bitcoin could be closer than we think.
Why are cryptocurrencies threatened by quantum computers?
The technology behind quantum computers enables much faster calculations compared to what we know from our regular PCs or even existing supercomputers. The threat to Bitcoin is that quantum technology could make it possible to derive your private keys from your public keys when you make a transaction. Once your private key is exposed, anyone who has access to it has control over your bitcoins.
How can Bitcoin defend itself?
First of all, there are different views about Bitcoins current capability to handle attacks from quantum computers. While some scientists say that the emergence of the first quantum computer will doom bitcoin, others are more optimistic. While a quantum computer could derive your private key from your public key, it would still have a hard time decrypting your public key, because this one was run through a number of one way hash functions, resistant to quantum computing. However nobody knows for sure what would really happen when the first quantum computer strong enough was used to decrypt bitcoin. Therefore, security experts suggest to upgrade the bitcoin protocol from SHA-256 to SHA-384, since the latter is a more secure form of cryptography.
In the end, as quantum computers evolve, so does the possibility to use them for safer encryption. Let's just hope that in case of an immediate threat, the bitcoin community can come to a consensus over establishing the necessary update 😅
Sources / further read:
https://medium.com/the-quantum-resistant-ledger/be-prepared-for-quantum-computing-era-bb1a9ec6cd35
https://news.bitcoin.com/is-bitcoin-at-risk-as-google-and-ibm-aim-for-50-qubit-quantum-computers/