Computer Science GCES OCR
-
Cpu Architecture Performance And Embedded Systems Ocr5 主题
-
Primary And Secondary Storage Ocr6 主题
-
Data Storage And Compression Ocr12 主题
-
Units Of Data Storage Ocr
-
Processing Binary Data Ocr
-
Data Capacity And Calculating Capacity Requirements Ocr
-
Converting Between Denary And Binary Ocr
-
Binary Addition Ocr
-
Converting Between Denary And Hexadecimal Ocr
-
Converting Between Binary And Hexadecimal Ocr
-
Binary Shifts Ocr
-
Representing Characters Ocr
-
Representing Images Ocr
-
Representing Sound Ocr
-
Compression Ocr
-
Units Of Data Storage Ocr
-
Networks And Topologies Ocr6 主题
-
Wired And Wireless Networks Protocols And Layers Ocr6 主题
-
Identifying And Preventing Threats To Computer Systems And Networks Ocr2 主题
-
Operating Systems And Utility Software Ocr2 主题
-
Ethical Legal Cultural And Environmental Impact Ocr2 主题
-
Computational Thinking Searching And Sorting Algorithms Ocr3 主题
-
Designing Creating And Refining Algorithms Ocr5 主题
-
Programming Fundamentals And Data Types Ocr5 主题
-
Additional Programming Techniques Ocr7 主题
-
Defensive Design And Testing Ocr6 主题
-
Boolean Logic Diagrams Ocr2 主题
-
Programming Languages And Integrated Development Environments Ides Ocr3 主题
-
The Exam Papers Ocr2 主题
-
Structuring Your Responses Ocr3 主题
Encryption Ocr
Exam code:J277
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 ‘ciphertext‘, before being transmitted
-
The receiver uses the same master key to decrypt the cipher text back to ‘plaintext‘
-
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
Worked Example
A bank does not use encryption when data is transmitted through the network.
Give two reasons why the bank should use encryption [2]
How to answer this question
-
Answer must be ‘why’ the bank should use encryption and NOT just what encryption is. Give examples in your answer
Answer
-
Customer data cannot be understood if intercepted // The data will be meaningless
-
So that only authorised users can access the confidential material // protect confidential/personal/user/bank data
-
To follow legislation/Data Protection Act
Responses