Specific to the security of passwords: hashing, entropy, cracking, resets, lockouts, etc.
Passwords are a secret word or string used to protect a resource by preventing access except to those users who hold the password. Questions tagged [password] are likely to refer to the strength of passwords, entropy, protection schemes such as hashing, appropriateness of password length and complexity, lockout systems, password self-reset functionality etc
Hashes for passwords
You should never store passwords in the clear.
As discussed at How to securely hash passwords and Password security: past, present, future, the following key derivation function algorithms (and not fast or unsalted raw hash functions), are recommended for storing passwords for later verification: