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Compression & Encryption (Encryption (Encryption is the process of…

- - - - The fineness of detail that can be seen in an image - the higher the resolution of an image, the more detail it holds
        
        resolution is measured in dots per inch (dpi).
    - - The number of bits available to store an audio sample.
  - - - A form of compression that encodes digital files without losing detail.Files can also be restored to their uncompressed quality
    - - A form of compression that reduces digital file sizes by removing data.
    - - SUPERCHANNEL
        
        A form of compression where special data is selected for a special reason. This data is separated from the rest, and the rest is thrown out.
      - RLE
        
        simple form of data compressin which runs off data that sequences in which the same data value occurs consecutive times.
        
        Run Length Encoding
        
        Example
        
        [3,3][4,5][1,6][2,7],[4,9]
        
        333, 5555, 6, 77, 9999
        
        before
        
        after
  - - - compresses images to a maximum 8-bit colour depth, making it unsuitable for high-quality photographs. GIF is often used where transparency is needed on the graphic. GIF can also be used to store simple animated images.
    - - is a lossless compression type. It is often used where the graphic might be changed by another person or where the image contains layers of graphics that need to be kept separate from each other. It is high quality.
    - - often used for digital camera images because it has a fairly small file size for the quality that it displays. JPEG is a lossy format that offers a higher compression rate than PNG in the trade-off for quality.
- - - - The data or message is encrypted using an encryption algorithm.
        
        The opposite of encryption is decryption.
    - - 1
        
        Encrypting data stored on a laptop hard disk. This is important as a laptop might contain sensitive information and could be easily stolen.
        
        If the hard disk is encrypted, the information will be unreadable unless the thief also has the key
        
        2
        
        When sending sensitive information, such as passwords or credit card details, over the internet.
        
        When a website uses the HTTPS protocol the information being transferred is encrypted. This means that if the connection is intercepted, the information will be unreadable.
        
        3
        
        Encrypting a document, such as a spreadsheet, using software tools, before sending it to a colleague via the internet, for security purposes.
        
        4
        
        Encrypting satellite TV transmissions to prevent users who do not subscribe from watching TV shows.
  - - - EXAMPLE
        
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        Shift Key of +1
        
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