Zte Blade S6 User Manual page 22

If you interrupt the encryption process, you will lose data.
3. Touch Encrypt phone.
4. Enter your lock screen PIN or password and touch Next.
5. Touch Encrypt phone again.
The encryption process starts and displays its progress.
Encryption can take an hour or more, during which time your
phone may restart several times.
When encryption is completed, you're prompted to enter your
PIN or password.
Subsequently you must enter your PIN or password each time
you power on your phone in order to decrypt it.
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