Security Chapter 8 Objectives Societal impact of information and information technology –Explain the meaning of terms related to computer security and crime and determine ways to protect both a business and yourself –Identify areas of computer security vulnerability and ways to protect against them –Recall the definition of encryption and apply the XOR encryption technique –Recognize good and bad passwords based on password guidelines

Security Resources you can use Protecting your computer sound byte: on_1/0,8697, ,00.html Norton AntiVirus Response Center Web Page Test the vulnerability of your computer: –Gibson Research Corporation ( –Qualys (

Computer security vulnerability points Hardware – Software – People –

Backup Data and Files are vulnerable Primary defense against data loss Selective, incremental & full

Software Perform regular updates for Windowshttp://update.microsoft.com Microsoft update: Windows, Office, more Automatic updates Check with vendors for updates Verify notices independently

Hackers Def: Types of hackers: –White-hat –Black-hat –Script kiddies

What Hackers Do Steal information from computers: –Credit card numbers –Bank account numbers Internet packet sniffing Commit identity theft Create widespread computer attacks: –Backdoor programs (Trojan horse) Denial of service attacks

How Hackers Gain Access Direct access: –Hacking software Indirect access: –Internet connection

Firewall Def: Types of firewalls: –Norton Personal Firewall –McAfee Firewall –Zone Alarm –BlackICE PC Protection –Network routers

Computer Viruses What puts you at risk for viruses?

How to "Catch" a Virus attachments. Do not open attachments before checking –Is this from someone I know? –Is the message a sensible follow-up to the last message from the sender? –Is the content of the message something the sender would say to me? –Is there a reason for the sender to include an attachment? When in doubt, be cautious

Antivirus Software Def: –Scan files looking for virus signatures (unique code) –Provide options for deleting or fixing infected files Need to be updated frequently Examples: McAfee, Norton, and Sophos, Inc.

What Viruses Do Replicate themselves: –Slow down networks Display annoying messages Delete files Change computer settings Love Letter – Fastest spreading virus Melissa – Caused $80 million damage Nimda – Affected more than 1 million computers

Logical security Def: What are ways to protect your password?

Biometric identification systems –Fingerprint –Palm print –Iris scan –Face recognition technology

Encryption Def: Encrypted data can be safely stored or transmitted Why is this needed?

Encryption example Using Exclusive OR, XOR,  If bits are the same, result is 0; if different 1 Apply a key to the plain or clear text

Encryption example 0101 Cleartext (The hex digit 5)  1001 Key

Encryption example If the cleartext is the hex digit D and the XOR key is 1001, what is the encrypted text?

Encryption example Encrypt the word NO with the key

Assignment Using XOR and the key , determine the encrypted results for the ASCII text: PASSWORD Complete HTML3