Android全设备加密

这里有大概的步骤和常见问题处理。

值得一提的是Orig filesystem overlaps crypto footer region.  Cannot encrypt in place这个问题。CM的JIRA上有人贴出了详细步骤：

Reboot into recovery (I’m using 4EXT Recovery, though CWM Recovery should work too)

Make sure /system, /sdcard, and /data are all mounted

From an adb shell, make a tar backup of /data (make sure you first have enough space on your SD card):

/system/xbin/tar -C / -cf /sdcard/data.tar data

Figure out device name of /data partition:

grep /data /proc/mounts

As an example, let’s say the previous step gave you /dev/block/mmcblk0p23

Figure out the partition’s size and the new size of the /data filesystem:

data_dev_size=$(cat /sys/class/block/mmcblk0p23/size)

new_fs_size=$(( ((data_dev_size/2)-16)*1024 ))

Reformat /data with correct size (continuing with the example of mmcblk0p23):

umount /data

/system/bin/make_ext4fs -a /data -l $new_fs_size /dev/block/mmcblk0p23

Remount /data

Restore the backup of /data:

/system/xbin/tar -C / -xf /sdcard/data.tar

Reboot

The “Encrypt phone” option in the Settings app now properly encrypts /data on the phone.

注意备份还原一定不要用Recovery内置的，一定要按原文走tar手动，因为Recovery的还原会自动format，才做好的特殊大小的分区就没了……