continued from part 1 - Controller General of Patents, Designs, and ...

(12) PATENT APPLICATION PUBLICATION (21) Application No.6809/DELNP/2008 A
(19) INDIA
(22) Date of filing of Application :07/08/2008 (43) Publication Date : 24/10/2008
(54) Title of the invention : "ROBUST CIPHER DESIGN"
(51) International classification :G06F 21/24 (71)Name of Applicant :
(31) Priority Document No :174784
1)NDS LIMITED
(32) Priority Date :04/04/2006
Address of Applicant :ONE HEATHROW BOULEVARD,
(33) Name of priority country :Israel
286 BATH ROAD, WEST DRAYTON MIDDLESEX UB7 0DQ
(86) International Application No :PCT/IL2007/000364 U.K U.K.
Filing Date
:20/03/2007 (72)Name of Inventor :
(87) International Publication No :WO 2007/113796 1)MANTIN ITSIK
(61) Patent of Addition to Application
Number
Filing Date
:NA
:NA
2)GRABOVSKY AHARON
(62) Divisional to Application Number :NA
Filing Date
:NA
(57) Abstract :
In an iterated block cipher, a method for round key encryption and key generation, the method including providing a first function Fi
and a second function Fj, providing a round key generation function, the round key generation function being operative to utilize, in
any given round, exactly one of the first function Fi, and the second function Fj, providing a round mixing function, the round mixing
function being operative to utilize, in any given round, exactly one of the first function Fi, and the second function Fj, utilizing the
round key generation function in at least a first round to generate a second round key for use in a second round, and utilizing the round
mixing function in at least the first round to mix a first round key with a cipher state, wherein one of the following is performed in the
first round the round key generation function utilizes the first function Fi to generate the second round key for use in the second round,
substantially simultaneously with the round key mixing function utilizing the second function Fj to mix the first round key with the
cipher state, and the round key generation function utilizes the second function Fj to generate the second round key for use in the
second round, substantially simultaneously with the round key mixing function utilizing the first function Fi to mix the first round key
with the cipher state. Related apparatus and methods are also described.
No. of Pages : 36 No. of Claims : 47
The Patent Office Journal 24/10/2008 26267