Matsushita Electric Industrial Co., Ltd.

Takeshi Saijo

Takatoshi Ono

Makoto Tatebayashi

Syunji Harada

Yasuo Okumura

In a cryptography system, plaintext storage unit stores a plaintext. Encryption unit encrypts the plaintext to generate a ciphertext. First verification data generating unit generates first verification data, and second verification data generating unit generates second verification data. Decryption unit decrypts the ciphertext to generate a decrypted plaintext. First verification unit performs verification using the decrypted plaintext and the first verification data. Second verification unit performs verification using the first verification data, the ciphertext, and the second verification data. Display unit displays the results of the verifications.

ENCRYPTION DEVICE, DECRYPTION DEVICE, ENCRYPTION METHOD, DECRYPTION METHOD, CRYPTOGRAPHY SYSTEM, COMPUTER-READABLE RECORDING MEDIUM STORING ENCRYPTION PROGRAM, AND COMPUTER-READABLE RECORDING MEDIUM STORING DECRYPTION PROGRAM WHICH PERFORM ERROR DIAGNOSIS

The output data storage unit allocates a memory area and stores cipher text and plain text; the input data size calculation unit calculates the sizes of cipher text and plain text; the type storage unit stores a cryptographic processing type and an algorithm type; the type providing unit outputs the cryptographic processing type and the algorithm type to the type information storage unit ; the type information storage unit stores an output size table, cryptographic processing type information, and algorithm type information; the output data size judgement unit calculates an output data size according to an input data size, the cryptographic processing type, and the algorithm type.

Cryptographic processing apparatus cryptographic processing method and recording medium for recording a cryptographic processing program

A message receiving apparatus for receiving messages from a message transmitting apparatus generates first data for producing a display which urges a user of the message transmitting apparatus to input a message, and generates second data within the first data for specifying a conversion type for secret communication of the message. The message receiving apparatus sends the first data including the second data to the message transmitting apparatus and subsequently receives the message from the message transmitting apparatus. The message transmitting apparatus for transmitting messages to the message receiving apparatus receives the first data for producing the display and the accompanying second data for specifying the conversion type and produces the display according to the first data. On receiving the message inputted by the user in response to the display, the message transmitting apparatus converts the input message according to the second data and transmits the converted message to the message receiving apparatus.

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Obu, Japan

Takeshi Saijo