Blacklist (computing)
Password blacklists are very similar to username blacklists but contain more entries than username blacklists. Password blacklists are used to stop users from choosing passwords that are easily guessed or are well known and could lead to unauthorized access by malicious parties. Password blacklists are used as a layer of security, which sets the requirements of the password length and/or character complexity. This is because there are a lot of number password combinations that fulfill many password policies but are still easily guessed (i.e., Password123, Qwerty123).