The document discusses various methods for ensuring security in information systems and networks. It describes encryption techniques that scramble data during transmission and can only be unscrambled by authorized users with public and private keys. It also discusses firewalls that filter access to internal networks from the internet and intranets to deter hacking. Finally, it outlines other security measures like antivirus software, access controls, backup systems, and audits to evaluate security policies and ensure proper protections are in place.

1. Security Management
 The goal of security
management is the
accuracy, integrity,
and safety of all
information system
processes and
resources
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2. Internetworked Security Defenses
 Encryption
Data is transmitted in scrambled form
It is unscrambled by computer systems for
authorized users only
The most widely used method uses a pair of
public and private keys unique to each
individual
 Note: Each system has two keys public and private. Public is available to all. Suppose
computer 1 tries to communicate with computer 2 then it will encrypt message using public
key of computer 2. computer 2 will open it using its private key.
 Messages encrypted by public key will be opened by private key only and vice versa.
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3. Public/Private Key Encryption
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4. Internetworked Security Defenses
 Firewalls
A gatekeeper system that protects a
company’s intranets and other computer
networks from intrusion
Provides a filter and safe transfer point for
access to/from the Internet and other
networks
Important for individuals who connect to the
Internet with DSL or cable modems
Can deter hacking, but cannot prevent it
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5. Internet and Intranet Firewalls
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6. Denial of Service Attacks
 Denial of service attacks depend on three
layers of networked computer systems
The victim’s website
The victim’s Internet service provider
Zombie or slave computers that have been
commandeered by the cybercriminals. These
are mostly unguarded computers.
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7. Defending Against Denial of Service
 At Zombie Machines
Set and enforce security policies
Scan for vulnerabilities
 At the ISP
Monitor and block traffic spikes
Traffic spikes are peak on web sites and often
causes crash. Content delivery** network kind
of distributed systems help in controlling traffic
 At the Victim’s Website
Create backup servers and network
connections
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8.  A content delivery network (CDN) is a system of
distributed servers (network) that deliver
webpages and other Web content to a user
based on the geographic locations of the user.
The closer the CDN server is to the user
geographically, the faster the content will be
delivered to the user.
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9. Internetworked Security Defenses
 Email Monitoring
Use of content monitoring software that scans
for troublesome words that might compromise
corporate security
 Virus Defenses
Centralize the updating and distribution of
antivirus software
Use a security suite that integrates virus
protection with firewalls, Web security,
and content blocking features
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10. Other Security Measures
 Security Codes
 Multilevel password system
 Encrypted passwords
 Smart cards with microprocessors
 Backup Files
 Duplicate files of data or programs
 Security Monitors
 Monitor the use of computers and networks
 Protects them from unauthorized use, fraud, and destruction
 Biometrics
 Computer devices measure physical traits that make each
individual unique
 Voice recognition, fingerprints, retina scan
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11.  Computer Failure Controls
 Prevents computer failures or minimizes its effects
 Preventive maintenance
 Arrange backups with a disaster recovery organization
 Computer system fails because of electrical
supplies, telecommunication problems, virsuses,
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12. Other Security Measures
 In the event of a system failure, fault-tolerant systems have
redundant processors, peripherals, and software that provide
 Fail-over capability: shifts to back up components
 Fail-save capability: the system continues to operate at the
same level
 Fail-soft capability: the system continues to operate at a
reduced but acceptable level
 A disaster recovery plan contains formalized procedures to follow
in the event of a disaster
 Which employees will participate
 What their duties will be
 What hardware, software, and facilities will be used
 Priority of applications that will be processed
 Use of alternative facilities
 Offsite storage of databases
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13. Information System Controls
 Methods and
devices that
attempt to
ensure the
accuracy,
validity, and
propriety of
information
system
activities
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14.  Information system controls are methods and
devices that attempt to ensure the accuracy,
validity and propriety of information system
activities.
 Control total make total of all inputs OR outputs
 Checkpoints ensure that required information is
available for processing
 Hardware control is control of communication
between various parts of system. It is mostly job
of operating system.
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15. Auditing IT Security
 IT Security Audits
Performed by internal or external auditors
Review and evaluation of security measures
and management policies
Goal is to ensure that that proper and
adequate measures and policies are in place
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16. Protecting Yourself from
Cybercrime
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