1. A scanning apparatus configured to scan a document output by an image processing apparatus, the image processing apparatus including a feature value generating means for generating feature values of given pages of a document including N pages, N being an integer not less than 2; an embedding means for embedding the generated feature values of the given pages in other pages corresponding to respective given pages; and an output means for outputting the document in which the feature values of the given pages have been embedded in the corresponding other pages by the embedding means, wherein the embedding means embeds a feature value of a k-th page in a j-th page, k being a natural number satisfying 1<=k<=N and j being a natural number satisfying 1<=j<=N and j not=k, wherein j is k+1 when 1<=k<=N−1, wherein j is 1 when k is N, wherein the feature value generating means generates feature values of k-th page (k=N) before the feature value generating means generates feature values of k-th page (1<=k<=N−1), and wherein the embedding means embeds a feature value of a k-th page (k=N) in a jth page before the generating means generates a feature value of the j-th page, the scanning apparatus comprising: a scanning means for scanning the output document to generate images; a getting means for getting the feature values from the generated images; and a judging means for judging whether the scanned document is original or not on the basis of the feature values, wherein the judging means generate feature values of given pages of the scanned document, compare the generated feature values and the gotten feature values and judge whether the output document is original or not on the basis of the result of the comparison.