Title:
DEVICE AND METHOD FOR SCRAMBLING AND DESCRAMBLING MPEG STREAM DATA
Document Type and Number:
Japanese Patent JP3965722
Kind Code:
B2
Abstract:
PROBLEM TO BE SOLVED: To provide a device and a method capable of protecting MPEG stream data from unauthorized use without increasing the processing loads of a CPU for decoding the cipher of the MPEG stream data.
SOLUTION: At the time of judging that it is a ciphered stream in a step 30, a cipher decoding code stored in a RAM is read in the step 32, ciphered data are accessed in the steps 34-38 and the data are decoded by the cipher decoding code. In the step 38, the ciphered data of the total of 8 bytes that are the third byte of a packet start code, a stream ID, a PES(program elementary stream) packet length and a sequence header attached to packet data at the head of a GOP(group of pictures) are decoded. That is, since a data amount to be decoded is little, the processing loads of the CPU are reduced.
Inventors:
Hideaki Takahashi
Application Number:
JP15439697A
Publication Date:
August 29, 2007
Filing Date:
May 28, 1997
Export Citation:
Assignee:
Brother Industries, Ltd.
International Classes:
G06F21/10; H04L9/14; H04N7/167; H04N21/2347; H04N21/4405; (IPC1-7): H04N7/167
Domestic Patent References:
| JP8265725A | ||||
| JP10145773A | ||||
| JP6303609A | ||||
| JP6090451A |
Attorney, Agent or Firm:
Akito Tashita
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