The Risk of Data Interception & Theft
Data can be very valuable to criminals, so it needs to be kept secure. With our data passing through so many networks, or being stored in the cloud, there are lots of opportunities for hackers to access it.
Hackers may:
- Copy data for themselves, and then use it or sell it to other (such as someone's personal details or credit card information)
- Change data to give the recipient false or misleading information
- Delete data, to destroy information and cause harm to organisations
More information on data interception and theft is in topic 1.4 Network Security.
Wireless and Wired Security
Wireless networks are especially at risk of data interception. Wi-Fi uses radio waves to transmits data, but radio does not just travel between the sending and receiving devices — it travels outwards in all directions. Another device could "listen-in", even from a different room.
Data transferred via wired connections are more secure, but certainly not "hack-proof"
Encryption
Encryption involves converting the original message (plaintext) into a scrambled version (ciphertext) using a sequence of numbers (a key).
When the intended recipient received the ciphertext, they can convert it back (decrypt) it back to the original plaintext.
If the ciphertext is intercepted or stolen, the hacker cannot understand the message because they do not have the key required to decrypt it.
Encryption Example
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Alfie wants to send a message to Bev, but he wants to keep it private.
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Alfie uses a key, a complex number, to encrypt the plaintext into ciphertext.
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Bev receives the ciphertext.
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Bev has a key which will decrypt the ciphertext back to plaintext so she can understand the message.
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If the message is intercepted during transmission, it cannot be understood by the hacker because they do not have the key.
Shift Cipher
A very simple form of encryption is the shift cipher. This involves shifting characters by a set number, which is used as the key).
To decrypt the message, the ciphertext characters are shifted back by the key value.
Try it Yourself
Click here to try your own shift cipher.