Security

• In what sense are files not actually deleted even if you empty the recycle bin on Windows or empty the trash on macOS?

• Technically speaking, what is a cookie in the context of HTTP? And how, using cookies, does a web server actually remember that you’re logged in?

• If a mobile phone is protected with a 4-symbol passcode, whereby each symbol is a decimal number (0 through 9), how long might it take to guess that passcode if each guess takes 1 second to check?

• If a mobile phone is protected with a 6-symbol passcode, whereby each symbol is a decimal number (0 through 9), an uppercase letter (A through Z), or a lowercase letter (a through z), how long might it take to guess that passcode if each guess takes 1 second to check?

• While you might think it’s more secure (and clever!) to use numbers that resemble letters instead of the letters themselves in your password, it isn’t really. Why not?

• Suppose you’ve forgotten your password to some website. Even though you can likely reset your password via a link on the website, odds are no one at the company can actually tell you your forgotten password. Why not?

• What does it mean if a website requires two-factor authentication? What might those two factors be?

• What does it mean if a website requires two-factor authentication? What might those two factors be?

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