A backup and restore module allows for block level cloud-based back up and restore of a storage volume of a computer. Original content of a block of a disk volume that is being modified by a write operation is stored in a point-in-time snapshot in a cloud storage. The original content may be stored in a hidden volume in the computer prior to being stored in the cloud storage. The original content may be encrypted for storage. To roll back the computer by restoring the disk volume, the snapshot is retrieved from the cloud storage. The original content is copied from the snapshot back to the block to restore the disk volume. The hidden volume may be searched for other original contents yet to be included in the snapshot in the cloud storage, and the original contents may be copied back to corresponding blocks to restore the disk volume.