Abstract: A scheme for message delivery which can guarantee an authenticity of a user, a reliability of message delivery, and an authenticity of the message deliver, while preventing an illegal act, and which can prove them at later time. In this scheme, when the user requests a delivery of a message to the information provider, the information provider carries out a user authentication of the user according to a zero knowledge interactive proof protocol using check bits E, transmits a ciphertext C in which a message M is enciphered according to a secret key cryptosystem by using a work key W, as a part of the check bits E, and delivers the message to the user in units of one bit or a plurality of bits. Then the information provider carries out a record management of a log data H for the zero knowledge interactive proof protocol.

Abstract: A storage control system for a print image data in a print control apparatus includes a unit for generating a print image expressed by a set of a plurality of dots as a digital data having a dot carrying a two-dimensional address corresponding to a bit, an address conversion unit for converting a digital data carrying a two-dimensional address into a digital data carrying a one-dimensional address, and a full-dot memory for storing a digital data carrying a one-dimensional address in a one-dimensional address structure.