Archives: Theory

Asymmetric Encryption

Asymmetric encryption (sometimes called public key encryption) is a form of encryption where a pair of keys are responsible for encrypting and decrypting data. This is different to symmetric encryption where the same key is used to…

Symmetric Encryption

What is encryption? Encryption is the conversion of data (plain text) into a form that is unreadable (ciphertext). Encryption allows us to protect data during transmission and make it useless if hacked from a server. The…

Copyright and Plagiarism

When looking at intellectual property rights we need to consider two key areas, copyright and plagiarism. Plagiarism Plagiarism occurs when a person takes another person’s ideas/work and claims it as their own. Although in itself…

High and Low Level Languages

A computer program is a list of instructions that enable a computer to perform a specific task. Computer programs can be written in high and low level languages, depending on the task and the hardware being…

Error Detection

There is always the chance that data has been corrupted (changed in some way) during transmission. This is true regardless of the distance of transmission. To avoid having corrupted data it is really important that computers check…

Data Compression

Compression is used to reduce file sizes – something which is essential in an era of online video streaming and media sharing. Without compression, we would: Fit less music, videos or photos onto your smart…

Selection

Selection statements  (sometimes called conditional statements) can be defined as code (statements) that is executed only when a certain condition is satisfied. Selection is a powerful tool to control when and which code statements will run. Think…

Iteration

Iteration is the term given to the repetition of a block of statements (code) within a computer program. Basically, think loops! There are 3 types of iteration that you need to learn for GCSE: FOR .. TO…

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