Encryption (OCR GCSE Computer Science)

Encryption

What is encryption?

• Encryption is a method of scrambling data before being transmitted across a network in order to protect the contents from unauthorised access

• While encryption is important on both wired and wireless networks, it's even more critical on wireless networks due to the data being transmitted over radio waves, making it easy to intercept

How is wireless data encrypted?

• Wireless networks are identified by a 'Service Set Identifier' (SSID) which along with a password is used to create a 'master key'

• When devices connect to the same wireless network using the SSID and password they are given a copy of the master key

• The master key is used to encrypt data into 'cipher text', before being transmitted

• The receiver uses the same master key to decrypt the cipher text back to 'plain text' 

• To guarantee the security of data, the master key is never transmitted. Without it, any intercepted data is rendered useless

• Wireless networks use dedicated protocols like WPA2 specifically designed for Wi-Fi security

How is wired data encrypted?

• Wired networks are encrypted in a very similar way to a wireless network, using a master key to encrypt data and the same key to decrypt data

• Encryption on a wired network differs slightly as it is often left to individual applications to decide how encryption is used, for example HTTPS