Bitcoin's security is built on a one-way mathematical relationship, making it computationally impossible for modern computers to break elliptic curve cryptography. However, a future quantum computer could change this by deriving private keys from public keys and draining funds.
There are two ways a quantum machine could attack Bitcoin: the long-exposure attack and the short-exposure attack. The long-exposure attack targets coins sitting idle onchain or in transactions waiting in the memory pool, while the short-exposure attack targets coins in motion.
Developers are considering various upgrades to prevent this threat, including removing public keys with BIP 360. This proposal removes the public key permanently embedded on-chain and visible to everyone by introducing a new output type called Pay-to-Merkle-Root (P2MR).