I. Passwords are an important security measure that require complexity to prevent unauthorized access. Standards recommend passwords be at least 8 characters including 3 of 4 character types and not based on dictionary words.
II. Passwords should be complex, unique, and not related to the user. Common substitutions like 0 for o don't strengthen passwords.
III. Passwords must be kept secret, changed if compromised, and different for different accounts and levels of access. Secure transmission is also important.