An information processing device which embeds a number of partial information items produced from predetermined information in an image, comprising: an image dividing unit configured to divide an image into a number of division images in a lattice formation to generate the division images; an information assigning unit configured to assign the partial information items to the division images generated by the image dividing unit; an information embedding unit configured to embed the partial information items assigned by the information assigning unit, in the division images, wherein the information assigning unit assigns all the partial information items to a set of division images located in a predetermined direction; and an information dividing unit configured to divide the information to be embedded into a number of partial information items; characterized in that: the information embedding unit is further configured to measure a distribution of the intensity value of picture elements in the division images; wherein when the result of the measurement is smaller than a threshold value, the information embedding unit does not embed the assigned partial information item in the corresponding division image; and the information assigning unit is configured to calculate an integer x by the formula x = (ai + bj + m) mod N where a, b, and m are predetermined integers and N is the number of the partial information items, wherein x is an integer ranging from 0 to N-1, and assign an x-th one of the partial information items to one of the division images located at two-dimensional space coordinates (i, j) corresponding to the image when a first condition that the number N and the intergers a and b are relatively prime and a second condition (a 2 + b 2)(mod)N = 0 are satisfied, or when a first condition that the number N and the intergers a and b are relatively prime and a second condition that (a 2 + b 2) and N are relatively prime are satisfied; wherein the image is rotated by 90 degrees. an image dividing unit configured to divide an image into a number of division images in a lattice formation to generate the division images; an information assigning unit configured to assign the partial information items to the division images generated by the image dividing unit; an information embedding unit configured to embed the partial information items assigned by the information assigning unit, in the division images, wherein the information assigning unit assigns all the partial information items to a set of division images located in a predetermined direction; and an information dividing unit configured to divide the information to be embedded into a number of partial information items; the information embedding unit is further configured to measure a distribution of the intensity value of picture elements in the division images; wherein when the result of the measurement is smaller than a threshold value, the information embedding unit does not embed the assigned partial information item in the corresponding division image; and the information assigning unit is configured to calculate an integer x by the formula x = (ai + bj + m) mod N where a, b, and m are predetermined integers and N is the number of the partial information items, wherein x is an integer ranging from 0 to N-1, and assign an x-th one of the partial information items to one of the division images located at two-dimensional space coordinates (i, j) corresponding to the image when a first condition that the number N and the intergers a and b are relatively prime and a second condition (a 2 + b 2)(mod)N = 0 are satisfied, or when a first condition that the number N and the intergers a and b are relatively prime and a second condition that (a 2 + b 2) and N are relatively prime are satisfied; wherein the image is rotated by 90 degrees.