How Does a “Collision” in Hashing Relate to the Security of the PoW Process?

A hash collision occurs when two different inputs (in this case, two different block headers/nonces) produce the exact same hash output. If a collision were found in the SHA-256 algorithm, it would severely compromise the security of Bitcoin.

An attacker could create a malicious block with the same hash as a legitimate one, undermining the immutability of the chain. The security of PoW relies on the extreme improbability of finding a collision.