As an example, imagine a system which only allows 4 digit PIN codes. This means that there are a maximum of 10,000 possible PIN combinations.
From the example above, PIN security could be increased by:
* Increasing the length of the PIN
* Allowing the PIN to contain characters other than numbers, such as * or #
* Imposing a 30 second delay between failed authentication attempts
* Locking the account after 'x' failed authentication attempts
Will try to implement the option #3 & #4 in OpnSuSe using SuSEfirewall
open your favorite editor and edit file: /etc/sysconfig/SuSEfirewall2:
# Add the following rule
# Now Restart firewall:
Now attacker will just have 3 attempts to break in.
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