CIPHERING DEVICE AND CIPHERING METHOD - 株式会社日立製作所

Title:

CIPHERING DEVICE AND CIPHERING METHOD

Document Type and Number:

Japanese Patent JP3901909

Kind Code:

B2

Abstract:

PROBLEM TO BE SOLVED: To combine the advantages of block cipher and stream cipher by making the number of bits in a key stream block larger than the number of bits in a plaintext block.
SOLUTION: A key stream generator KS generates an intermediate key in the system of a pseudo-random number sequence S in accordance with a cryptographic key K. The KS is a pseudo-random number generator used for stream cipher like WAKE, SEAL or RC4, for example. The KS can be the block cipher of a counter mode or a hash function with a counter. The intermediate key S is inputted to a mix function MX. The mix function MX receives a plain sentence message P, connects it with the pseudo-random number sequence S and generates a cipher text C. The number of bits in a key stream block is larger than the number of bits in the plaintext block.

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Inventors:

Soichi Furuya
Michael law

Application Number:

JP2000108334A

Publication Date:

April 04, 2007

Filing Date:

April 10, 2000

Export Citation:

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Assignee:

株式会社日立製作所

International Classes:

G06F12/14; H04L9/20; G06F21/60; G06F21/62; G09C1/00; H04L9/06; H04L9/18; H04L9/26; (IPC1-7): H04L9/26; G06F12/14; G09C1/00

Domestic Patent References:

JP9160490A

Other References:

暗号理論の基礎,共立出版株式会社,1996年11月 1日,p.8-13
暗号コンピュータ・データ保護の新展開,自然社,1986年 2月10日,p.55-96

Attorney, Agent or Firm:

Sanshin Iwao

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