It's not just petty criminals after your iPhone, it might one day also be the feds. And they won't go to Apple, they'll come straight to you.
Since the introduction of iOS 8 almost a year ago, Apple has included device encryption, which secures device data from hackers, thieves, and government agencies.
After the company was accused of cooperating with US government surveillance programs, Apple wanted to ensure that it couldn't be forced to hand over data stored on its customers' devices. In doing so, it gave its customers the encryption keys to their device's data.
How? A simple lock-screen passcode.
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Turning on device encryption is easy and takes just one minute. Here's how you do it.
1. Go to the Settings on your iPhone.
2. Go to Touch ID & Passcode.
3. Select the Turn Passcode On option if it's not already. From there, you will be able to set either a strong six-digit or longer numerical passcode, or alphanumeric password.
4. Set a strong passcode. Entering a codes like "123456" will warn you that it's easy to guess.
At this screen, selecting Passcode options will let you set a longer numerical passcode by choosing Custom Numeric Code. This offers the benefit of only giving you numbers to press on the lock screen.
You can also set a Custom Alphanumeric Code, which significantly improves your device's security. According to Apple, setting a six-digit alphanumeric passcode with lower-case letters and numbers would take about five years to break if every combination was tried.
5. Once your passcode is set, you will return back to the Settings menu. Scroll down to the bottom of the page, you should see: "Data protection is enabled." That means your device is now encrypted, and nobody except you can access the data on that device.
HOW TO SECURE YOUR IPHONE