What is confidentiality
The term confidentiality is used in information security to indicate whether someone has unauthorised access to information. Someone watching you type in your pincode at an ATM, is compromising the confidentiality of that pincode.
If you leave your PC while you are still logged on, and someone starts browsing through your files in your absence, that would be an attack on the confidentiality of your information. If that person changes a file, that would be an attack on integrity and deleting that file would be an attack on availability.
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