Electrical computers: arithmetic processing and calculating – Electrical digital calculating computer – Particular function performed
Reexamination Certificate
2008-06-24
2008-06-24
Mai, Tan V. (Department: 2193)
Electrical computers: arithmetic processing and calculating
Electrical digital calculating computer
Particular function performed
Reexamination Certificate
active
07392272
ABSTRACT:
An arithmetic unit and an arithmetic method that output no information necessary for decryption or encryption to the outside and can perform a self-protecting function when an illegal attack is made. A command monitoring part (44) monitors input command sequences. In a first sequence, a process key in a first stage is calculated from a hardware key (Khd) and is then written to a key storing part (47). In each of the following sequences, a process key in a next stage is calculated from a process key stored in the key storing part (47). When commands of predetermined contents are inputted in predetermined order, a content key is calculated and then written to the key storing part (47). Encrypted data is decrypted with the content key, and the result is outputted from data output means (63). When an illegal attack is made, initialization is performed by selecting fixed value data (Kf) as key data (Ksl) and selecting fixed value data (Df) as input data (Ein).
REFERENCES:
patent: 4937574 (1990-06-01), Wright
patent: 5784462 (1998-07-01), Tomida et al.
patent: 2004/0090391 (2004-05-01), Kondo
patent: 2006/0265228 (2006-11-01), Ando
patent: 61-251255 (1986-11-01), None
patent: 64-500227 (1989-01-01), None
patent: 11-109853 (1999-04-01), None
patent: 11-505055 (1999-05-01), None
patent: 11-266240 (1999-09-01), None
patent: 11-513864 (1999-11-01), None
patent: 2001-016655 (2001-01-01), None
Abe Miki
Matsuda Hiromi
Morinaga Eiichiro
Tanaka Masao
Mai Tan V.
Oblon & Spivak, McClelland, Maier & Neustadt P.C.
Sony Corporation
LandOfFree
Calculation device and calculation method does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Calculation device and calculation method, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Calculation device and calculation method will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2799833