Abstract: The authentication system has a signing station and a certifying station. The signing station divides the data to be transmitted into a plurality of data, a hash unit creates a plurality of authenticators by applying a different one-way function to each of the data. In the certifying station, a separating unit divides the data into a plurality of data, a hash unit creates a plurality of authenticators by applying a different one-way function to each data, and a comparing unit compares the authenticators prepared anew with the authenticators separated from the received data and checks the authentication of the data from the comparison.

Abstract: A decryption processing unit decrypts encrypted content data using a license key Kc. When an elapsed time after reception of the license key (Kc) does not exceed a hold time at a time of the license key (Kc) included in reproduction control information (ACp), reproduction of encrypted content data continues. When the elapsed time exceeds the hold time at a time, the license key (Kc) is discarded, and a reproduction control unit again obtains a license key (Kc) from a memory card. Discarding and reobtaining license key (Kc) continues until an allowable output count of license key (Kc) from the memory card becomes zero. As a result, a reproduction time of encrypted content data can be controlled safely.

Abstract: A memory card includes a user ID hold unit holding user ID data provided to identify the user of the memory card, a first protection information memory unit holding first protection information restricting access to memory card, and a second protection information memory unit holding second protection information restricting access for each content data. Memory card refers to the user ID data to identify the user of the reproduction apparatus of interest and prohibits any unauthorized user from changing first and second protection information.

Abstract: A memory card (110) conducts an authentication process with a server based on data stored in an authentication data hold unit (1400). The memory card (110) extracts a first session key (Ks1) from a server by a decryption process and a transaction ID from the data applied on a data bus (BS3). The memory card (110) generates a second session key (Ks2) through a session key generation unit (1418), and transmits to the server, as the keys to encrypt content data in receiving decryption of content data, the second session key (Ks2) and a key (KPm(1)) unique to the memory card (110) in an encrypted state with the first session key (Ks1). The transaction ID and the second session key (Ks2) stored in the log memory (1460) are used in the redistribution process.

Abstract: An information management method restoring electronic data using backup information upon the loss of electronic data stored on a recording medium. Information stored in a predetermined area of the recording medium having medium-specific information is encrypted using medium-specific information or a key generated therefrom and is derived outside the predetermined area.

Abstract: An advertisement management device generates and manages advertisement information and an advertisement identifier, a tag management unit generates a tag identifier and tag information unique to the tag identifier, and manages the tag identifier, the tag information, and the advertisement identifier generated by the advertisement management device in associated manner. The tag management unit sends the tag identifier and the advertisement identifier to the radio tag. A reader reads the tag identifier and the advertisement identifier from the radio tag, sends the tag identifier to the tag management unit, and sends the advertisement identifier to the advertisement management unit. The tag management unit sends tag information corresponding to the tag identifier received from the reading unit to a display unit, and the advertisement management unit sends advertisement information corresponding to the advertisement identifier received from the reading unit to the display unit.

Abstract: Before accepting a setting request from a predetermined manager in a plurality of date-and-time managers capable of issuing a date-and-time setting request, a setting request from any manager can be accepted. After accepting a setting request from a predetermined manager, only the setting request from the predetermined manager can be accepted. A date and time can be set in response to an accepted date-and-time setting request.

Abstract: A storing unit stores a plurality of pieces of tag information to be stored in a single radio-frequency-identification tag. A responding unit transmits, in response to a request from a reader/writer, part of the stored tag information to the reader/writer.

Abstract: A license server (10) includes a CRL database (306) holding a revocation list recording therein classes predetermined corresponding respectively to a memory device, such as a memory card, and a content reproduction circuit, such as a cellular phone, that are subjected to revocation of distributing, reproducing and transferring content data. A distribution control unit (315) suspends an operation distributing content data if the distribution is addressed to a class listed on the revocation list. The revocation list is also held in the memory card and distribution control unit (315) in distributing content also transmits information for updating the revocation list in the memory card.

Abstract: A cellular phone has distributed encrypted content data and an encrypted content key stored in a memory. The encrypted content key data read out from the memory is decrypted by a decryption processing unit using key data Kp stored in a Kp hold unit, and then applied to a audio reproduction module. A decryption processing unit decrypts encrypted content data read out from the memory using a content key Kc extracted by the decryption processing unit to reproduce content data Dc.

Abstract: An LA (License Agent) (or a license chip having the same function as the LA) is disposed in a PC (Personal Computer), a content distribution server, and a medium attached to a PD (Private Device or Portable Device) that use a license for electronic data. A content and electronic data are encrypted corresponding to a license. The encrypted content and electronic data are distributed among them. However, the license is distributed between the LAs as safe communication means. Thus, the license can be correctly managed and transferred.

Abstract: A memory card performs decryption processing to extract a session key from data applied from a server to a data bus over a cellular phone network. An encryption processing unit encrypts a public encryption key of memory card based on a session key, and applies the same to the server via data bus. A register receives and stores data such as a decrypted license ID and a user ID from the server, and a memory receives and stores encrypted content data applied from a data bus and encrypted with a license key.

Abstract: A memory card (110) decodes data delivered to a data bus (BS3) and extracts a session key (Ks1) sent from a server from the data. Based on the session key (Ks1), an encrypting section (1406) encrypts a public encryption key (KPm (1)) of the memory card (110) and delivers it to a server through the data bus (BS3). The memory card (110) receives data including a license key (Kc) and a license (ID) encrypted with the public encryption key (KPm (1)) different with memory card to memory card, decrypts the data, encrypted it again with uniquely given secret key (K(1)), and stores it in a memory (1415).

Abstract: A personal identification terminal includes a plurality of identification means or a plurality of identification levels that are selectable for use, and means for selecting one of the plural identification means or one of the identification levels in accordance with identification means/level setting information that is received from a server every time when receiving a request for identification from the server. The personal identification terminal sends used means/level information that indicates one of the identification means or one of the identification levels that was used for the real identification back to the server in a format that enables detection of an alteration thereof together with a result of the identification.

Abstract: A radio tag system including at least one radio tag that includes a plurality of data areas and a key storage area that stores key information corresponding to at least one data area; and a managing unit that manages access to the radio tag, and that includes a request receiving unit that receives from a user, a request to issue key information that allows access to one of the data areas, and an issuing unit that issues the key information in response to the request received.

Abstract: A program execution control device adapted to authorize execution of a program specified in advance comprises an expected value table storage section that stores at least a set of an expected value obtained by applying a predetermined function to the program specified in advance and the identifier of the specified program, an input interface that allows at least a set of an input program and the identifier of the input program to be input externally, a function operating section that acquires a computed value by applying a predetermined function to the input program, a comparing section that compares the expected value corresponding to the identifier of the input program out of the expected values in the expected value table and the computed value and an output interface that externally outputs the input program in response to agreement of the compared two values.

Abstract: A memory card 110 extracts a session key Ks from the data applied onto a data bus BS3 by carrying out a decryption process. An encryption processing unit 1406 encrypts a public encryption key KPcard(1) of memory card 110 based on session key Ks, and applies the encrypted key to a server via data bus BS3. A memory 1412 receives from a server data such as license key Kc, license ID data License-ID and user ID data User-ID encrypted with a public encryption key KPcard(1) differing for each memory card for storage, and receives encrypted content data [Dc]Kc encrypted with license key Kc from data bus BS3 for storage.

Abstract: A file processing unit comprises a first signature information producing unit that produces first signature information in accordance with a predetermined rule utilizing the data of a file designated by a file close request issued in an application used in a computer system, and a signature information storage control unit that stores the first signature information, correlated with the file designated by the file close request, in a storage unit.

Abstract: A cryptographic communication method is provided in which a cryptographic communication is performed by an easy operation even if both enciphered data and unenciphered data are mixed to be handled. In the transmission side, a communication key is used for enciphering data to be transmitted, and in the reception side the same communication key as in the transmission side is used for decoding received data. In the transmission side, an individual key that is different from the communication key is used for enciphering the data to be transmitted, the enciphered data are decoded by using the individual key first, and then the decoded data are enciphered by using the communication key so that the enciphered file can be transmitted.

Abstract: A storage medium stores encrypted electronic data, a medium personal number which is unique for each storage medium and encrypted permission information. At least the medium personal number is written onto the storage medium in an un-rewritable form which a user computer cannot rewrite.