Unauthorized Access

• Internal controls, like a transaction log (audit trail).
• identification/authentication
• firewalls for the internet. All communication with the internet goes over the firewall computer.
• printout waste is a weak link!

Authentication

How to convince a computer who you are:

Passwords or identification numbers

If the login to some system depends on a password, it may not be too safe. There are only 26^6=308,915,776 possible 6-character passwords if you use only characters, no numbers or special symbols. That's possible to crack for a computer. Therefore passwords are safer if the system realizes when several unsuccessful attempts are made and responds accordingly. For credit card pin numbers, AT machines have this property.

Possessed objects

• Credit Card
• Authentication via encryption, to be more precise, via public key encryption, is also possible and works very well. It is sometimes called a digital signature.

Biometric devices

like fingerprints.

Callback Systems

you dial in, then the system calls you back.

go to the Encryption page

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Erich Prisner, April 2005