Is it a good security measure to change the file extension name? For example, a file with .jpg extension changed to .pdf or any other extension name relatively safe from prying eyes?
It will protect you from general users, and prevent most applications from opening the file, but there is still a header or footer in the file that determines it’s association, so it’s still reversible, if you look at the file, generally in a hex editor, so no if your worried about people that have some mid-high level computing experience.
Steganography, is interesting, it’s a bit more advanced, but it’s the embedding data within a filetype’s extra data positions, occasionally using two filetypes one that is read from a header and the other read from a footer. More:http://en.wikipedia.org/wiki/Steganography
