Title:
BLOCK ENCRYPTION DEVICE, BLOCK DECRYPTION DEVICE, BLOCK ENCRYPTION METHOD, BLOCK DECRYPTION METHOD AND PROGRAM
Document Type and Number:
WIPO Patent Application WO/2011/105367
Kind Code:
A1
Abstract:
Disclosed are a block encryption device and a block encryption method that enable tweakable block encryption with tweaks of an indeterminate length, which possesses theoretical resistance to a birthday attack. A block encryption device is provided with: a keyed hash unit which generates an n-bit mask value S and an m-bit intermediate value V (where m is a positive integer less than n/2) by means of a keyed hash function using a key K2, and a b-bit tweak key T is entered when a block cipher has an n-bit block and an n-bit key and the tweak length is set to b bits; a tweak-dependent key derivation unit which, after the intermediate value V has been padded by n bits, uses a key K1 to encrypt the intermediate value V with an n-bit block cipher to generate an n-bit tweak-dependent key L; and a masked block encryption unit which, after the mask value S has been added to n-bit unencrypted information M, generates encrypted information C by encrypting with an n-bit block cipher using the tweak-dependent key L as a key, and adding the mask value S to the result.
Inventors:
MINEMATSU KAZUHIKO (JP)
Application Number:
PCT/JP2011/053832
Publication Date:
September 01, 2011
Filing Date:
February 22, 2011
Export Citation:
Assignee:
NEC CORP (JP)
MINEMATSU KAZUHIKO (JP)
MINEMATSU KAZUHIKO (JP)
International Classes:
G09C1/00
Domestic Patent References:
| WO2008018303A1 | 2008-02-14 | |||
| WO2009128370A1 | 2009-10-22 | |||
| WO2010024004A1 | 2010-03-04 |
Other References:
MOHAMED ABO EL-FOTOUCH ET AL.: "A New Narrow Block Mode of Operations for Disk Encryption", ISIAS'08. FOURTH INTERNATIONAL CONFERENCE, September 2008 (2008-09-01), pages 126 - 131
KAZUHIRO MINEMATSU ET AL.: "Generalization and Extension of XEX Mode", PROCEEDINGS OF THE 31ST SYMPOSIUM ON INFORMATION THEORY AND ITS APPLICATIONS, October 2008 (2008-10-01), pages 526 - 531
KAZUHIRO MINEMATSU: "Beyond-Birthday-Bound Security Based on Tweakable Block Cipher", 16TH INTERNATIONAL WORKSHOP, FSE 2009, January 2009 (2009-01-01), pages 308 - 326
KAZUHIRO MIMEMATSU ET AL.: "Generalization and Extension of XEX* Mode, IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences, E92-A(2)", THE ENGINEERING SCIENCE SOCIETY, 1 February 2009 (2009-02-01), pages 517 - 524
KAZUHIRO MINEMATSU: "An Approach to Beyond- Birthday-Bound-Security, 2009 Nen Symposium on Cryptography and Information Security (SCIS2009) Yokoshu", 2009 NEN SYMPOSIUM ON CRYPTOGRAPHY AND INFORMATION SECURITY JIMUKYOKU, 20 January 2009 (2009-01-20), pages 3B1 - 1
KAZUHIRO MINEMATSU ET AL.: "Generalization and Extension of XEX Mode", PROCEEDINGS OF THE 31ST SYMPOSIUM ON INFORMATION THEORY AND ITS APPLICATIONS, October 2008 (2008-10-01), pages 526 - 531
KAZUHIRO MINEMATSU: "Beyond-Birthday-Bound Security Based on Tweakable Block Cipher", 16TH INTERNATIONAL WORKSHOP, FSE 2009, January 2009 (2009-01-01), pages 308 - 326
KAZUHIRO MIMEMATSU ET AL.: "Generalization and Extension of XEX* Mode, IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences, E92-A(2)", THE ENGINEERING SCIENCE SOCIETY, 1 February 2009 (2009-02-01), pages 517 - 524
KAZUHIRO MINEMATSU: "An Approach to Beyond- Birthday-Bound-Security, 2009 Nen Symposium on Cryptography and Information Security (SCIS2009) Yokoshu", 2009 NEN SYMPOSIUM ON CRYPTOGRAPHY AND INFORMATION SECURITY JIMUKYOKU, 20 January 2009 (2009-01-20), pages 3B1 - 1
Attorney, Agent or Firm:
KATO, Asamichi (JP)
Asamichi Kato (JP)
Asamichi Kato (JP)
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Claims: