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Security precautions

Learning Intentions

  • Describe the role of a firewall

  • Describe the use of encryption in electronic communication

Success Criteria

  • I can describe how a firewall operates and how it can help improve security of a system
  • I can describe how encryption is used to protect data and content in a electronic communicaiton

Firewalls

  • A firewall is a special type of software that is designed to prevent unauthorised access to and from a network.
  • A firewall is composed of rules that manage who can access what.
  • In reality, these rules affect which ports of applications can be used to access what.

Firewalls

  • A firewall is a special type of software that is designed to prevent unauthorised access to and from a network.
  • A firewall is composed of rules that manage who can access what.
  • In reality, these rules affect which ports of applications can be used to access what.

Filtering messages

  • A firewall can also be used to check the content of data being passed through a network.
  • There are two types of firewalls, hardware firewalls and software firewalls.

Hardware firewalls

  • A hardware firewall runs on a router on the network (since a router is a network type used to connect multiple networks together, in this case a LAN and the Internet)
  • A standard router firewall often only certain allows ports to go out and not come in, for example port 80/443 are the ports used for browsing the web and so the router would be configured to only allow those ports in and out but not port 2031 for Minecraft.
  • A hardware firewall is also more difficult for malware to affect (although not impossible)

Software firewalls

  • A software firewall runs on the local system and decides what programs should be allowed to access what.
  • For example, you may get a warning on Windows about running Minecraft over a network you'll occasionally get a Windows Firewall popup

Proxy servers

  • A proxy server, or web proxy is a computer often used along with a firewall
  • A proxy server is a special server that is designed to access webpages requested by other computers on the network.
  • The school has a proxy server that makes all requests automatically for you when you request a webpage.

Proxy servers

  • The server can then filter all of the content
    • This leads to safer browsing but also more controlled browsing
  • The proxy server can also have a set of rules that determine what can and cannot be viewed. This is called content filtering.

Encryption

the process of converting messages in ordinary language, or other information into a secret coded form that cannot be interpreted without knowing the secret method for interpretation, called the key.

Encryption

  • Encryption means transforming a piece of data (the source data) into code (the encrypted data) to prevent unauthorised users viewing it.
  • One common use of encryption is when sending emails securely over the internet.
  • An encryption algorithm such as AES is used to encrypt the data using a key and then the software is used again to decrypt the data.

Brute force attacks

  • A brute force attack is a when a fast and powerful computer system is used to attempt many different combinations of, say passwords, to eventually figure out something about the encryption or the correct password
  • A program to decrypt something doesn't actually take a lot of time to write either
  • With advancements in technology happening every day, it's possible we'll need to move to even stronger encryption very soon
$p = "Pass"
function letters()
  $str = ""
  for($i = 0 to 26)
    $l = integer_to_character($i + 65)
    $str = $str & $l
  end for
  return $str
end function
function main()
$str = ""
for ($i = 1 to 5)
  $str = $str & letters()
  print($str)
end for
end function

Brute force attacks

  • This program will decrypt the word Pass after just a few attempts
$p = "Pass"
function letters()
  $str = ""
  for($i = 0 to 26)
    $l = integer_to_character($i + 65)
    $str = $str & $l
  end for
  return $str
end function
function main()
$str = ""
for ($i = 1 to 5)
  $str = $str & letters()
  print($str)
end for
end function

Brute force attacks

  • This program will decrypt the word Pass after just a few attempts
$p = "Pass"
function letters()
  $str = ""
  for($i = 0 to 26)
    $l = integer_to_character($i + 65)
    $str = $str & $l
  end for
  return $str
end function
function main()
$str = ""
for ($i = 1 to 5)
  $str = $str & letters()
  print($str)
end for
end function

This program does have a few drawbacks.

Firstly this program assumes you cannot be locked out after incorrectly entering a password.

Secondly, it only checks letters and not numbers or symbols

Answer the following questions:

  1. What is the difference between software and hardware firewalls?
  2. How does a firewall keep a network or system safe?
  3. How does a proxy server keep a network safe?
  4. Explain how encryption works and how it can keep data secure
  5. Explain the term brute force attack.

Review questions

Plenary

Pick 4 key words and provide a description for them.

 

 

 

 

 

 

 

 

 

 

  • source data
  • encryption
  • brute force
  • rule
  • proxy server
  • encryption key
  • software firewall
  • hardware firewall
Presentation Overview
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JB
Security Precautions
© 2020 - 2024 J Balfour
10:40 | 29-04-2024
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