Password hashes are transformed password values created by a one-way hashing function. Instead of storing a plain text password, a system stores the hash and compares new login attempts by hashing the submitted password and checking whether the results match. This reduces the damage if a database is exposed, because the original passwords are not directly saved.
In cyber security, password hashes matter because they are often a target in breaches. Attackers who steal them may try offline cracking with dictionaries, brute force, or leaked password lists, especially if weak algorithms or missing salts are used. Defenders look for strong password hashing methods, unique salts, rate limits, and signs that stolen hashes could be reused in credential stuffing or account takeover. Even when passwords are hashed, their exposure can still create real risk.