The four digit PIN is a common part of our everyday life. From
door codes to ATMs to cell phones, some of us use a four digit
PIN daily. Although it sounds a bit counter intuitive, using
only three unique numbers in your PIN instead of four different
numbers will your make your PIN more secure. In other words, a
PIN like 3963 is more secure than one like 1872. Most PINs tend
to be four digits and have options from ten characters (0-9).
The brute force strength of this is 10,000 different
combinations (104=10,000). This is probably sufficient to ward
off a manual brute force attack. The fact that most ATM card
skimmers include PIN loggers seems to bear this out. It’s pretty
common knowledge, however, that straight brute force is often
unnecessary. Residue and oils on your fingers will leave traces.
Just a tilt to the light will often tell the attacker exactly
what digits are used in your PIN and sometimes the PIN is used
so often that light is not even necessary. When an attacker
knows that there are only four