Bcrypt is a password-hashing scheme designed to store passwords safely instead of saving them in plaintext. It combines a unique salt with a configurable work factor, or cost, to make each hash slower and harder to compute. The salt helps prevent attackers from using precomputed tables, and the work factor increases the time and resources needed for each guess.
In cyber security, bcrypt matters because stolen password databases are often attacked offline. Once hashes are exposed, an attacker can test guesses locally without alerting the service. Bcrypt does not stop cracking, but it raises the cost, especially against large password lists. It is strongest when paired with long, unique passwords, a modern cost setting, and protections like multi-factor authentication and checks against known breached passwords. If users reuse weak passwords, even bcrypt-protected hashes can still be cracked and used in credential stuffing elsewhere.