Passwords also help to determine accountability for all transactions and other changes made to system resources, including data. If you share your password with a colleague or friend, you may be giving an unauthorized individual access to the system. Authentication of individuals as valid users, via the input of a valid password is required to access any shared automated information system. Each user is accountable for the selection, confidentiality and changing of passwords required for authentication purposes. Since you are responsible for picking your own password, it is important to be able to tell the difference between a good password and a bad one.
Bad passwords jeopardize the information that they are supposed to protect.
Good ones do not. Following are some simple rules you should keep in mind about passwords. Passwords should be kept confidential and should never be shared. Passwords should not be written down. Never use the same password twice.