This image was acquired from
flickr. It was marked as Public Domain or CC0 and is free to use. To verify, go to the source and check the information there.
Keywords from Image Description:
u.s. national archives usnationalarchives confederate spy confederatespy cipher code secret rose greenhow rosegreenhow spy mourning paper mourningpaper naraarcid rose o'neal greenhow roseonealgreenhow cryptography document From File Unit Letters from Mrs. Rose O'Neal Greenhow Also Notes etc. in Her Handwriting Record Group Created