Cryptography – Video cryptography – Video electric signal modification
Reexamination Certificate
2003-09-03
2010-06-29
Kim, Jung (Department: 2432)
Cryptography
Video cryptography
Video electric signal modification
C380S239000, C713S160000
Reexamination Certificate
active
07747016
ABSTRACT:
A data transmitting and receiving method for improving transmission and reception efficiency can be obtained by improving the security through update of a control key and reduction of the frequency of the authentication and key exchange process. An STB1transmits encrypted digital data Kw (D) obtained by encrypting digital data D using a work key Kw, and an encrypted work key Kc (Kw) obtained by encrypting the Kw using a control key Kc. The Kc is periodically or non-periodically updated, and an identifier L identifying the Kc is assigned to each Kc. A VTR device2decrypts the received Kc (Kw) using the Kc obtained by performing the authentication and key exchange process with the STB1, decrypts the Kw (D) received using the Kw to obtain the D. It is determined whether or not the Kc has been updated while the reception process is suspended by referring to the transmitted L when the reception process is suspended and then resumed. If it is determined that the Kc has been updated, then the authentication and key exchange process is performed again to obtain the updated Kc.
REFERENCES:
patent: 4613901 (1986-09-01), Gilhousen et al.
patent: 5247576 (1993-09-01), Bright
patent: 5381481 (1995-01-01), Gammie et al.
patent: 5412722 (1995-05-01), Sherly et al.
patent: 5742680 (1998-04-01), Wilson
patent: 59-134949 (1984-08-01), None
patent: 61-177046 (1986-08-01), None
patent: 63-15136 (1988-06-01), None
patent: 64-062043 (1989-03-01), None
patent: 04-297157 (1992-10-01), None
patent: 07-336328 (1995-12-01), None
patent: 08-331119 (1996-12-01), None
patent: 09-18468 (1997-01-01), None
patent: 09-18469 (1997-01-01), None
patent: 10-021645 (1998-01-01), None
patent: WO 97/01231 (1997-01-01), None
Office Action from Japanese Patent Office for Application No. JP 10-162667 dated Mar. 9, 2004, with partial English translation.
Office Action corresponding to application No. CN 99800678.5 dated Mar. 25, 2005.
Japanese language search report for International Application No. PCT/JP99/01606 dated Jul. 21, 1999.
Office Action from Japanese Patent Office for Application No. JP 10-089098 mailed Sep. 2, 2003.
Supplementary European Search Report for EP 99 91 0755, Apr. 19, 2009.
Gotoh Shoichi
Iitsuka Hiroyuki
Nishimura Takuya
Takechi Hideaki
Yamada Masazumi
Kim Jung
Okeke Izunna
Panasonic Corporation
RatnerPrestia
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