Methods and apparatus for encoding, decoding, encrypting and decrypting an audio signal, recording medium therefor, and method of transmitting an encoded encrypted audio signal
First Claim
1. A method of encoding an audio signal, comprising the steps of:
- splitting the audio signal into a first signal component for permitting only comprehension of its contents and a second signal component for high quality reproduction; and
encrypting and encoding only said second signal component.
1 Assignment
0 Petitions
Accused Products
Abstract
An information encoding method for encrypting and encoding information signals, such as PCM audio signals, in which the information signals can be reproduced with low quality even in the absence of the key information for encryption. For carrying out the information encoding method, the input PCM signals are converted by a transform unit into frequency signal components which are encoded by a signal component encoding unit. High frequency range side signal components are sent to an Ex-OR gate to take an Ex-OR of the high frequency range side signal components with a pseudo random bitstring from a pseudo random bitstring generating unit. A codestring generating unit 1606 generates a codestring having the low frequency range side components from a signal component encoding unit and the encrypted high frequency range side components from the Ex-OR gate.
89 Citations
30 Claims
-
1. A method of encoding an audio signal, comprising the steps of:
-
splitting the audio signal into a first signal component for permitting only comprehension of its contents and a second signal component for high quality reproduction; and encrypting and encoding only said second signal component. - View Dependent Claims (2, 3, 4, 5)
-
-
6. A recording medium having an encoded digital signal recorded thereon, the recording medium being prepared by the steps of:
-
splitting an audio signal into a first signal component for permitting only comprehension of the signal contents and a second signal component for high quality reproduction; encrypting and encoding only the second signal component; and recording the first signal component and the encrypted encoded second signal component on the recording medium. - View Dependent Claims (7, 8, 9, 10)
-
-
11. A decoding apparatus for decoding an encoded audio signal, comprising:
-
means for splitting the encoded audio signal into a first signal component of low quality permitting only comprehension of the signal contents and into a second signal component for high quality reproduction; and means for selecting whether or not the second signal component should be decoded depending upon a presence or absence of a key signal for encryption. - View Dependent Claims (12, 13, 14, 15)
-
-
16. An apparatus for encoding an audio signal, comprising:
-
means for splitting the audio signal into a first signal component for permitting only comprehension of its contents and a second signal component for high quality reproduction; and means for encrypting and encoding only said second signal component. - View Dependent Claims (17, 18, 19, 20)
-
-
21. A method of transmitting an audio signal, comprising the steps of:
-
splitting the audio signal into a first signal component for permitting only comprehension of the signal contents and a second signal component for high quality reproduction; encrypting and encoding only the second signal component; and transmitting the first signal component and the encrypted encoded second signal component. - View Dependent Claims (22, 23, 24, 25)
-
-
26. A method of decoding an encoded audio signal, comprising the steps of:
-
splitting the encoded audio signal into a first signal component of low quality permitting only comprehension of the signal contents and into a second signal component for high quality reproduction; and selecting whether or not the second signal component should be decoded depending upon a presence or absence of a key signal for encryption. - View Dependent Claims (27, 28, 29, 30)
-
Specification