Compression, Encryption and Hashing A Level Resources

​A Level Computer Science: ​​Compression, Encryption and Hashing

This module contains:

  • An editable PowerPoint lesson presentation
  • Editable revision handouts
  • A glossary which covers the key terminologies of the module
  • Topic mindmaps for visualising the key concepts
  • Printable flashcards to help students engage active recall
  • A quiz with answer key to test knowledge and understanding of the module
Compatible with the following examination boards
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​​Compression, Encryption and Hashing

​File handling is one of the primary functions of a computer system. Based on the type of data that needs to be stored, several types of file formats are available. Each file format occupies certain storage space.
An image file with good quality occupies around 1 MB and a video file needs to store 25 frames per second occupying a large storage space. Thus, compression methods are used to reduce the size of the files. Compression is also helpful in reducing the download time of image, audio and videos from the internet. In this chapter, different types of files formats and compression methods are explained.

This ​A Level Computer Science module introduces ​​Compression, Encryption and Hashing to your students, explaining:

  • ​Why compressing files is important
  • How are text, image, audio and video files compressed
  • Effects of compressing a file
  • What are the various file formats
  • Compression algorithms: Run-length encoding and Huffman coding
  • Encryption: Symmetric and Asymmetric
  • Hashing, digital certificates and digital signatures

More ​​Exchanging data Modules

​​​Compression, Encryption and Hashing is one lesson in our ​Exchanging data module. ​The other theory lessons can be found below: