Your library or organization should consider adopting the following rules for network passwords:Passwords may not be blankPasswords must be seven or more characters longPasswords must use a mixture of letters (upper and lower case), numbers and charactersPasswords must be changed on a regular basisPasswords must be successively unique (in other words, users shouldn't use the same password repeatedly)Passwords must never be written down or posted in an insecure location (such as on a monitor)In addition, consider adding these prohibitions:Passwords cannot be the user's name, the name of someone in their family, or their birth datePasswords must not be constructed by adding a numeral or character to the beginning or end of a regular word; this is too easily guessed (e.g."chair1")