| Explain how a firewall works | Numbered doors called ports are opened so that only certain traffic is allowed to pass through |
| What is packet filtering | Acceptance or blocking of packets based on their port number |
| What is a proxy server | A server that sits between a public network and a private network |
| What is stateful inspection | Examining the contents of a packet before deciding whether to allow it through the firewall |
| Explain what symmetric encryption is | Symmetric encryption uses the same private key to encrypt and then decrypt the data being transferred |
| Explain what asymmetric encryption is | Use of two separate but related keys to encrypt and decrypt |
| What is the definition of a public key | A key that can be obtained by anyone |
| What is the definition of a private key | A key that only the one device knows/ has access to |
| What is a firewall | A firewall is either software or hardware that controls access to and from a network |
| Can a firewall be classed as a proxy server | Yes |
| How do proxy servers improve security? | Manage every packet that passes to them |
| How can a firewall create some sort of anonymity to devices on a network | When a device in a private network sends a packet through a firewall and into a public network, the packet’s “sender” address is that of the firewall, rather than the device’s private IP address. This provides some degree of anonymity to devices on private networks as their private address is never sent beyond the private network |
| What is the issues with symmetric encryption | The key has to be agreed upon first
More damage: Once someone has the key they can decrpyt everything |
| What methods allow a firewall to work | packet filtering
proxy server
stateful inspection |
| Describe what keys are used when Craig encrypts using asymmetric encryption to Frank | Craig enecpytes the message with Franks public key
Frank decrypts the the message with his own private key |
| How can worms, trojans and viruses be addressed | improved code quality
monitoring
protection |
| What are worms | Malicious software that can self-replicate between computers |
| How can we pick up worms | Devices within a network
Users downloading and running a malicious file |
| What are trojans | malware that is disguised as a benign file |
| How can we pick up trojans | Email attachments
Downloaded from malicious websites |
| What are viruses | malware which require a host file in which to reside |
| How can we pick up viruses | Computers over a private network
Internet
Physical media: Hard drives, Flash drives, Optical disks |
| what are worms, trojans and viruses are all types of | malware |
| How does improved code quality protect devices from malware | Malware often exploit bugs in code that enable them to take hold of a computer system |
| State what moneriting is and does | Specialist pieces of software that scan the files on a computer and remove any suspicious files |
| How does protection protect devices from malware | Reduces the exposure and opportunity of malware |
| Give some examples of the 'protection' technique in stopping malware | Antivirus software
Modern operating systems |
| Give some examples of the 'monitoring' technique in stopping malware | Training
General caution |
