You can encrypt all the data on your phone: Google Accounts, application data, music and other media, downloaded information, and so on. If you do, you must enter a numeric PIN or password each time you turn on your phone. Note that this is the same PIN or password that you use to unlock your phone without encryption, and cannot be set independently.
Encryption provides additional protection in case your phone is stolen, and may be required or recommended in some organizations. Consult your system administrator before turning it on. In many cases the PIN or password you set for encryption is controlled by the system administrator.
Before turning on encryption, prepare as follows:
When you're ready to turn on encryption:
The Encrypt phone button is dimmed if your battery's not charged or your phone's not plugged in. If you change your mind about encrypting your phone, touch the Back button. If you interrupt the encryption process, you will lose data.
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 complete, you're prompted to enter your PIN or password.
Subsequently, you must enter your PIN or password each time you power on your phone, to decrypt it.