1. An information processing system which processes data including graphic characters, which are the elements of character text, in one or more items, wherein one or more operators have security levels for said data, using cryptography, comprising: (a) a memory means connected to a display means and peripheral devices; (b) an ordinary information processor connected to said memory means for at least one of processing, generating, receiving/transmitting, and loading/saving said data and for displaying said data on a screen of said display means; (c) a partial data selector connected to said memory means for selecting optional portions of said data consisting of said graphic characters within each of said items of said displayed data on said display means, by using a range-designating method, and for memorizing the positions of said selected portions, so as to allow one or more programs/one or more said operators to specify said selected portions to be ciphered; (d) a security level setter connected to said memory means for setting n (.gtoreq.0, n max .gtoreq.1) said security levels to said selected portions, wherein said portions having said security level zero are not enciphered; (e) an encryptor means connected to said memory means for copying said selected portions to memory buffers and enciphering said selected portions in said memory buffers by using encipher keys determined in accordance with said security levels of said selected portions; (f) a converter means connected to said memory means for converting said enciphered portions in said memory buffers from a binary mode to a displayable mode which is displayed on said display means; (g) a data-type keeping and a data storing means connected to said memory means for executing at least one of replacing said selected portions with predetermined displayable symbols and further storing said converted enciphered portions into each of the same said items, and replacing said selected portions with said converted enciphered portions in said displayable mode; (h) a deconverter means connected to said memory means for copying said converted enciphered portions to said memory buffers and deconverting said converted enciphered portions in said memory buffers from said displayable mode to said binary mode; and (i) a decrypter means connected to said memory means for deciphering said deconverted enciphered portions by using decipher keys determined in accordance with said security levels of said deconverted enciphered portions and returning each of said decrypted portions and deleting said converted enciphered portions.