Cryptography – Communication system using cryptography – Symmetric key cryptography
Reexamination Certificate
2006-10-17
2006-10-17
Hua, Ly V. (Department: 2135)
Cryptography
Communication system using cryptography
Symmetric key cryptography
C380S269000
Reexamination Certificate
active
07123720
ABSTRACT:
A key scheduler for an encryption apparatus using a DES encryption algorithm is disclosed. The key scheduler includes: a first permutation choice unit for permuting a 56-bit block; a first register for storing left 28 bits among the 56-bit block from the first permutation choice unit in accordance with a clock signal; a second register for storing right 28 bits among the 56-bit block from the first permutation choices unit in accordance with the clock signal; a first and a second shift units for shifting the 28-bit blocks stored in the first and the second registers to the left by a first predetermined number of bits and outputting shifted 28-bit blocks to the first and the second registers respectively; a second permutation choice unit for permuting the 28 bits stored in the first and the second registers, thereby generating a first subkey; a third and a fourth shift units, each for shifting the 28 bits stored in the first and the second registers to left by a second predetermined number of bits; and a third permutation choice unit for permuting the 28 hits stored in the third and the fourth shifters, thereby generating a second subkey.
REFERENCES:
patent: 4947428 (1990-08-01), Guillou et al.
patent: 5675653 (1997-10-01), Nelson, Jr.
patent: 5835599 (1998-11-01), Buer
patent: 6108421 (2000-08-01), Kurdziel et al.
patent: 6272221 (2001-08-01), Tsunoo
patent: 6278783 (2001-08-01), Kocher et al.
patent: 6304658 (2001-10-01), Kocher et al.
patent: 6357009 (2002-03-01), Giles et al.
patent: 6381699 (2002-04-01), Kocher et al.
patent: 6400824 (2002-06-01), Mansoorian et al.
patent: 6442525 (2002-08-01), Silverbrook et al.
patent: 6816968 (2004-11-01), Walmsley
patent: 0 403 456 (1990-12-01), None
Hua Ly V.
Hynix / Semiconductor Inc.
Pillsbury Winthrop Shaw & Pittman LLP
LandOfFree
Key scheduler for encryption apparatus using data encryption... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Key scheduler for encryption apparatus using data encryption..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Key scheduler for encryption apparatus using data encryption... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3710912