Network Security Flashcards
All 14 cards in this deck
Why should an organisation use several network security methods together rather than just one?
No single method stops every threat, so combining them gives a greater level of security.
e.g. MAC address filtering keeps unknown devices off the network, but encryption is still needed in case data is intercepted.What is encryption?
Scrambling data using a key, turning plaintext into ciphertext, so that it cannot be understood by unauthorised users.
What name is given to a message before it has been encrypted?
Plaintext — an unencrypted message that is readable to anyone.
What name is given to a message after it has been encrypted?
Ciphertext — an altered message that is unreadable to unauthorised parties.
What is needed to encrypt and decrypt a message?
A key — a secret value used with the encryption algorithm to disguise and recover the message.
Why is data encrypted before it is transmitted across a network, especially a wireless one?
So that if it is intercepted by an unauthorised person it cannot be understood without the key.
True or false? Encryption stops data being intercepted while it is transmitted.
False. It does not prevent interception; it makes the intercepted data unreadable without the key.
What is a firewall?
Hardware or software that monitors incoming and outgoing network traffic and decides whether to allow or block specific traffic, based on a defined set of security rules.
What is a MAC address?
A unique physical address embedded in a device's network adapter (NIC) by the manufacturer. It identifies that device on a network.
Why is network security important to an organisation?
Any two of: its network holds personal and confidential data that only authorised people should see; stolen data could be used for fraud or identity theft; it could face legal action and lose customers' trust; an attack could change or delete data, or stop the network working.
Why does connecting computers in a network increase security risks?
More devices and users give an attacker more ways in, and once malware or an attacker is on one computer it can reach the others and any shared data.
How does authentication help to keep a network secure?
Users must prove who they are, e.g. with a username and password, before they can access the network. Only authorised people get access to its data and resources.
What is MAC address filtering?
A network security method that allows or blocks devices based on the physical (MAC) address embedded in their network adapter. A device's MAC address is checked against a list when it tries to connect.
When is MAC address filtering useful?
On a network used by a known, fairly fixed set of devices, e.g. a small office's wireless network. Only the approved devices are listed, so unknown devices such as visitors' phones cannot join.