Drawing a black box over a section of a GIF, JPG, or PNG image destroys the previous contents. I'd emphasize the distinction between layered and un-layered data formats. (This attack isn't a problem if the image never went through JPEG compression before your redaction.)ĭitto Ben N, but let me add a couple of points that are too long to fit as comments. It never hurts to overwrite more information than necessary when you're concerned about secrecy. One possible thing to be wary of is JPEG compression artifacts around the secret data, which could be used to get clues about the shape of the text. Of course, Paint doesn't have any special effects, so you should be fine. Some effects can be undone almost perfectly, so make sure the one you use involves a lot of randomness or actual data destruction (e.g. If you use a blur rather than a plain opaque rectangle/brush, a determined attacker could try lots of different possibilities in the image to see what text(s) get close to your image when blurred. Any spaces in the blanked region provide information about the relative lengths of the data's parts/words (mentioned in David Schwartz's comment).The height of the region could tell attackers whether the text representation of the data has ascenders or descenders (like in the letters b and p).The width of the blanked region places an upper bound on the length of the secret data.(Paint doesn't.) There are some things to watch out for, though: The layer or layers are active for the current page.As mentioned in the answers to a very similar question, scribbling over part of an image will destroy the original pixels, assuming that your editor doesn't store any layers or undo history in the saved image.

In the Layer Properties dialog box, select the check box in the Active column for each layer you want to make active. On the Home tab, in the Editing group, click Layers, and select Layer Properties. Shapes you add to the page are automatically assigned to all of the active layers. You can designate more than one active layer. When you are ready to add windows, you can designate the wall layer as the active layer. All the shapes you add from then on are assigned to the electrical layer. If a shape is not already assigned to a layer, the shape is automatically assigned to the active layer when you add it.įor example, if you are ready to add electrical wiring shapes to a drawing of an office layout, you can make the electrical layer active. Making a layer active is a fast way to assign shapes to the layer as you add them to the page. Note: To assign a shape to more than one layer, press CTRL and click each layer.

Work in layers in ms paint