Some passwords are stored using specialized encryption algorithms known as hashes. Why is this an appropriate method?

Hashing is not encryption and does not use a cryptographic key - it is a keyless one-way transformation, so there is no key whose theft would allow direct reversal of hashes.

Because hashing is irreversible by design, the original password cannot be retrieved from the stored hash, which is why forgotten passwords must be reset rather than recovered.

Performance speed is not the security rationale for hashing passwords; in fact, intentionally slow hash functions like bcrypt are preferred precisely because speed would aid brute-force attacks.

Cryptographic hash functions are designed to be computationally irreversible, meaning even an attacker who obtains the entire password database cannot reverse a hash back to the original plaintext. This non-reversibility ensures that even in the event of a data breach, user passwords remain protected as long as the hash function and any salting mechanism are sound.