Types of Passwords
There are three main types of passwords.
Strings of Characters
At the most basic level, passwords are stings of characters, numbers
and symbols. Access to a keyboard or keypad allows entry of these
types of passwords. These passwords range from the simplest – such as
the three digit codes used on some garage door openers – to the more
complicated combinations of characters, numbers and symbols that are
recommended for protecting highly confidential information.
Strings of Characters plus a token
The next level in passwords is to require a string of characters,
numbers and symbols plus a token of some type. An example of this is
the ATM, which requires a card - the token - plus a personal
identification number or PIN. This is considered more secure, because
if you lack either item, you are denied access.
The third level in passwords is the biometric password. This is the
use of non-reproducible biological features, such as fingerprints or
facial features to allow access. An example of this is the retinal
scan, in which the retina – which is the interior surface of the back
of the eye is photographed.
The retina contains a unique pattern of blood vessels that are easily
seen and this pattern is compared to a reference. Biometric passwords
are the most sophisticated and are considered 'safer' but in reality a
password that you 'carry' in your finger or eye is no safer than a
strong password that you carry in your head, provided that the
software that uses the
password is correctly configured.