Mitsubishi Denki Kabushiki Kaisha

Nippon Telegraph and Telephone Corporation

Mitsubishi Electric Corporation

Mitsuru Matsui

Toshio Tokita

Shiho Moriai

Junko Nakajima

Masayuki Kanda

Kazumaro Aoki

Daisuke Suzuki

Ken Onishi

Sadayuki Inoue

Tohru Inoue

Yusuke Naito

Yoichi Shibata

Tomomi Kasuya

Hirosato Tsuji

Tetsuya Ichikawa

An encryption device divides a message M into blocks of b bits, so as to generate data M[1], . . . , data M[m]. The encryption device sets data Sof n=b+c bits to a variable S, updates the variable S by calculating a block cipher E using as input the variable S, then updates the variable S by calculating an exclusive OR using as input the variable S that has been updated and data X[i] that is data M[i] to which a bit string of c bits is added, and generates data C[i] by extracting b bits from the variable S that has been updated, for each integer i=1, . . . , m in ascending order. The encryption device generates a ciphertext C of the message M by concatenating the respective pieces of the data C[i] for each integer i=1, . . . , m. The encryption device extracts t bits from the variable S as an authenticator T, where t is an integer of 1 or greater.

Encryption device, decryption device, encryption method, decryption method, and computer readable medium

The object is to enable cipher communication even when a cipher key in a one-time pad cipher (Vernam cipher) is running short. A one-time pad encrypting part encrypts communication data by the one-time pad cipher by sequentially using part of a one-time pad cipher key stored in a one-time pad cipher key storage part, to generate encrypted data. A block-encrypting part encrypts communication data by a block cipher by using a block-cipher key stored in a block-cipher key storage part, to generate encrypted data. An encryption control part controls whether the communication data is to be encrypted by the one-time pad encrypting part, or by the block-encrypting part, depending on a remaining bit count of the one-time pad cipher key stored in the one-time pad cipher key storage part.

Encryption device, encryption system, encryption method, and encryption program

A pseudo-random number generatorgenerates a pseudo-random number by the following operation. At C.2, S[B] is determined from Bset in a second internal memory, and S[B] is determined from B. Then, R[J] is generated from S[I], S[B], and S[B]. At C.3, S[I] is newly generated based on S[B] and S[B]. At C.4, Bis updated from S(I). In the above, the relationship between R[J] and S(I) is cut off, which makes difficult to estimate S(I) from R[J], and security is increased. Further, since S[I], S[B], S[B], etc. have 4 bytes, the processing speed is high.

Pseudo random number generator

It is desired to share one circuit by an encryption unitand a decryption unit. A normal data transformation unit (FL)and an inverse data transformation unit (FL)are located at point symmetry on a non-linear data transformation unit, and a normal data transformation unit (FL)and an inverse data transformation unit (FL)are located at point symmetry on the non-linear data transformation unit. Therefore, the encryption unitand the decryption unitcan be configured using the same circuits.

Block encryption device using auxiliary conversion

Block cipher apparatus using auxiliary transformation

Block cipher using auxiliary transformation

A sub converterprovided in a data conversion apparatus for data encryption/decryption includes a data conversion function and a data transfer function or key transfer function, the sub converter converts data and transfers data that is nonlinear converted in a main converteror a key that is outputted from a key KL registerby switching between the data conversion function and the data or key transfer function.

Data conversion device and data conversion method

In a data transformation apparatus for transforming two arbitrary pieces of data of A input data and B input data, a first nonlinear transformation of the A input data is performed using a first key parameter, a transformed result is output, an XOR operation of the transformed result and the B input data is performed to output an XORed result as B intermediate data, and the B intermediate data is input to a next sub-transformation unit as B input data. On the other hand, the B input data is input to a next sub-transformation unit as A input data. A second nonlinear transformation of the B input data is performed using a second key parameter, the transformed result is output, an XOR operation of the transformed result and the B intermediate data is performed to output an XORed result as B intermediate data, and the B intermediate data is input to a next sub-transformation unit as B input data. The above configurations is connected in a cascade and the last A intermediate data and B intermediate data are output as transformation result.

Data transformation apparatus and data transformation method

An integer Z is divided by an integer I to obtain a remainder R . The integer I includes a polynomial of power of a basic operational unit of a computer. In this way, the integer I for divisor is limited based on the basic operational unit of the computer, thus a shift operation, which is required for a conventional operation method, can be eliminated. The remainder can be calculated by only addition and subtraction. Accordingly, a code size becomes compact and the remainder of the integer can be calculated at a high speed.

Method and apparatus for arithmetic operation and recording medium of method of operation

The present invention can be applied to a cipher processing apparatus, which includes a function F having a configuration of repeating process and inside of the function F, a function f having a configuration of repeating process is included. According to the invention, the cipher processing apparatus is configured by registers through for temporarily holding data, selectors A through C, through and a function f operating circuit for transforming data. An output data from the function f operating circuit is held in the register C and the selector C selects either to repeat the data transformation by the function operating circuit or not. When a cipher processing apparatus includes a function F having a configuration of repeating process and inside of the function F, a function f having a configuration of repeating process is included, the cipher processing apparatus can be embodied efficiently, which enables to reduce the circuit scale and to save electric power.

Growing community of inventors

Tokyo, Japan

Mitsuru Matsui