Reformatting a camera SD card or USB flash drive after its use so as to permanently delete files contained on it does not work. Almost any quality data recovery tool can reconstruct files on a reformatted camera memory card or flash drive. If you have been using these devices to transfer data of a sensitive personal nature and in operating under the assumption that a reformatting of said device will protect you, you are completely wrong. The only way to completely protect yourself from the possibility of someone taking any digital media recently used and reconstructing files stored on that media is to scramble the data completely by using a file eraser program.
These drive wipe programs work in a similar fashion to traditional paper shredders. They tear the information in the file into tiny pieces over and over again. By doing this in a random pattern it becomes a mathematical impossibility for anyone to reconstruct your private data. The processes used to shred file data are so effective as to be approved for permanent erasing of top secret information by the U.S. Department of Defense. Once you use a file shredder program to permanently delete files from your computer’s internal hard drive or any other type of digital media you need never worry again about someone seeing your private information.