Encryption should be supported for Android OS 3.0 (Honeycomb) and later.
To encrypt your Android phone, touch the Settings icon from a Home or All Apps screen, then go to Personal > Security > Encryption > Encrypt phone. Select Encrypt phone, then enter your lock screen PIN or password and touch Continue. Select Encrypt phone again and the encryption process will start.
To encrypt your Android tablet, go to Settings > Personal > Security > Encryption > Encrypt table. Select Encrypt tablet, then enter your lock screen PIN or password and touch Continue. Select Encrypt tablet again and the encryption process will start.