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)

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:

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

Answer the following questions:

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

Review questions

Plenary

Pick up to 3 key words and provide a description for them.

source data

encryption

firewall

brute force

rule

proxy server

encryption key

software firewall

hardware firewall