Dai Nippon Printing Co., Ltd.

Tetsuo Shinriki

Kazuyoshi Irisawa

Naoto Shibata

When in order to enable the use of a plurality of applications (APto AP) simultaneously, preparation commands, having identifiers attached, are provided according to the respective applications and working areas for the respective applications are secured inside a RAM (). By providing a verification command having a specific identifier, a verification process concerning a specific application is performed and a verification result is stored in the corresponding application working area. This verification result is used until the completion of a communication session. To make a specific application execute a desired process, a process executing command that designates an identifier attached to the corresponding application is provided. Adequate security can be ensured and yet a series of linked processes can be performed smoothly while switching among a plurality of application programs in the same communication session.

Portable information recording medium

Switching between a requiring mode and a non-requiring mode of password code checking is enabled by an IC card with a CPU for accessing an EEPROM. The general data in the EEPROM are stored upon attachment of error check codes. The memory area of EEPROM is partitioned into unit areas of 2-byte length and writing is performed according to unit areas. The MSB of a specific unit area Ux is used as a checking requirement flag with '1' being defined as checking 'required' and &#x201c;0&#x201d; being defined as checking &#x201c;not required&#x201d;. In rewriting the checking requirement flag, an erasure process sets all bits in the unit area Ux to &#x201c;1&#x201d; and thereafter the desired flag is set in the MSB.

Portable information processor having password code checking function

Authentification data (R) comprising random numbers generated by a reader/writer () is given to an IC card (), encrypted by utilizing a secret key (a), and returned as encryption data (C). This encryption data (C) is decoded by utilizing an open key (&#x3b2;) to authentify the IC card. A set of past given authentification data (R) is stored in an authentification data storage section (): if another set of given authentification data (R) is the same as the set of past data, an encryption operating section () is prevented from executing an illegal statistical analysis technique by repeatedly giving encrypting operation the same set of authentiification data (R).

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Tokyo, Japan

Tetsuo Shinriki