It has been explained to me, albeit, in layman's terms, that one of the reasons our modern cryptography works so well on classical computers is that they rely on prime factorization which classical computers don't do so well. This has been key to maintaining our computers and networks secured. One of the things Quantum computers do better than classical computers is prime factorization. How will the advent of Quantum computing impact cryptography? Will technologies like blockchains and bitcoin be affected?
For a long time people have speculated about what this will mean for bitcoin, many have made predictions where quantum computers destroy bitcoin, but we need to be honest the cryptography used in bitcoin is used all over the world in the banking industry and to protect confidential information so bitcoin will not be the only one affected, however there are already quantum resistant algorithms, so whenever it seems that the technology is getting close to break the cryptography of bitcoin the developers could update the code of bitcoin to avoid this fate.