A Boolean expression uses the logical terms AND, OR, and NOT (often along with parentheses and quotation marks) to come up with a "true" or "false" statement. Search for "sticks OR stones" and you'll match anything that has either term; search for "sticks AND stones" and you'll match only items that contain both. For the most part, it's that simple.
You can use Boolean expressions in Spotlight, Mail rules, Calendar searches, and many third-party apps. Unfortunately, Boolean logic isn't currently supported in Contacts, iTunes, or the App Store.
Create a secure password
A good password — one that will resist almost any attempt at cracking — should be long and unguessable, with a combination of uppercase and lowercase letters, digits, and punctuation. But when we're asked to create such passwords, many of us encounter a mental block.
You often hear mnemonic tips like "Make a long sentence, and then your password becomes the first letter of each word (and that can include capitalization and punctuation)." That wouldn't be terrible advice if you had only one or two passwords to remember. But you probably have dozens, or maybe even hundreds. (I have well over 700 unique passwords.) One of the worst security mistakes you can make is reusing the same password in multiple places — if one password were stolen, leaked, or cracked, an attacker could access all the accounts that use the same password. Keeping every password unique contains the damage.
The sane way to create and remember lots of long, random passwords is to use software that does all the work for you, syncs your passwords securely across all your devices, and automatically fills them in when needed. If you use Safari on OS X and iOS, iCloud Keychain can do all this for you. If you want to use multiple browsers or non-Apple operating systems, if you want longer and stronger passwords, or if you'd like additional features such as storing software licenses and other personal data, you might prefer a third-party app such as AgileBits' 1Password (5 mice, $50), Dashlane Premium ($39 per year), or LastPass (4.0 mice, free).
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