[0024] Hereinafter, embodiments of the decoding key recording method and reproduction method of a compressed audio file according to the present invention will be described in detail with reference to the accompanying drawings.
[0025] See figure 2 , figure 2 What is shown is a structural diagram of an MP3 audio file in which the decryption key is distributed and recorded in an embodiment of the present invention.
[0026] By reference figure 1 As stated, the MP3 audio file includes at least one or more of a fixed-length header header with 4 bytes and an arbitrarily "variable length" frame recorded, including those recorded in the MP3 audio file. 128 bytes of tag information.
[0027] According to the decryption key method of the present invention, the encrypted compressed audio data is recorded in the above-mentioned frame domain, and the decrypted decryption key will be distributed and recorded in the several header records recorded in the front area of the MP3 audio file, in particular, each Recorded in the header information of the centralized management, allowing the user to arbitrarily designate the use of the defined "1" bit-long private bit. figure 2 When the decryption key is "0101", the private bits of the 4 centralized header information (Header 1, 2, 3, 4) record "0", "1", "0", and "1" respectively. In the frame corresponding to the header information of the first header, the reference information related to the decryption key is selected and recorded as non-encrypted data to shorten the full length of the MP3 audio file.
[0028] See image 3 , image 3 Shown is the structure diagram of the MP3 audio file in which the decryption key is distributed and recorded in another embodiment of the present invention. When the decryption key is "0101", the private bits of the 4 header information (Header 1, 2, 3, 4) recorded in the front area of the MP3 audio file are recorded with "0", "1", and " 0", "1", and in the frame corresponding to the fourth header information, the reference information about the decryption key is selectively recorded as non-encrypted data to shorten the total length of the MP3 audio file.
[0029] Figure 4 It is a structural diagram of the compressed audio file reproduction method according to the present invention applicable to an MP3 player. The MP3 player includes: a memory 10 in which several MP3 audio files are recorded and stored; according to the user's application and readout, they are recorded in the memory 10 MP3 audio file, the microprocessor 20 that detects and combines the decryption key; using the decryption key detected and combined by the microprocessor 20 to perform the decryption operation, the compressed audio data that has been decrypted is converted to the original audio data A memory 40 for decoding and decoding programs for decoding; an audio signal processor 30 for processing the above-mentioned decrypted and decoded audio data and reproducing audio signals; a liquid crystal display 50 for displaying a series of information for the above operations, etc. of. In addition, the decryption and decoding program memory 40 can be integrally included in the microprocessor.
[0030] Figure 5 Shown is the operation flowchart of the method for reproducing compressed audio files by the microprocessor 20 (see also Figure 4 ).
[0031] S10. When the user receives an application for reproduction of an MP3 audio file, he searches for any one of the MP3 audio files recorded and stored in the memory 10, retrieves, stores, and records the tail mark information of the MP3 audio file in the application for reproduction, including the information recorded in The file information of the mark information, such as the collection title, album cover, production date and genre of MP3 audio files;
[0032] S11: On the one hand, the screen is displayed on the liquid crystal display 50, and on the other hand, it detects and confirms the mark information of the MP3 audio file, and whether the information of the decryption key is scattered and recorded in several places.
[0033] S12. Search for the recording interval of the MP3 audio file requested for reproduction, and record the header information of the header in the previous area, for example, figure 2 and image 3 As shown, when the decryption key is scattered and recorded in the header information of 4 headers, the header information of the first to fourth headers is detected;
[0034] S13, in the microprocessor 20, firstly, search to confirm that the copyright bit of the copyright protection is displayed, and whether the bit value "1" of the copyright protection is recorded in the copyright bit of the header information of the first to fourth headers;
[0035] S14: Determine the result of the above confirmation, that is, determine whether the copyright bit="1", if not="1", enter the following S18 process;
[0036] S15, if the copyright bit is "1", the microprocessor 20 retrieves and stores the decrypted values of the private bits of the header information scattered in the first to fourth centralized management;
[0037] S16: Combine the retrieved and stored decryption values and complete the decryption key "0101";
[0038] S17, using the decryption key combined through the same process as the above, to decode and store the decryption program in the decoding program memory 40, to decode the respective audio data encrypted and recorded in the frame area;
[0039] S18, using the decoding program stored in the memory 40 of the above-mentioned decryption and decoding program, restore the compressed audio data that has been decrypted to the original audio data and output it to the audio signal processor 30.
[0040] S19 In the audio signal processor 30, the decrypted and restored audio data is subjected to signal processing as a reproduced audio signal, and a normal reproduction signal processing operation of reproduction output is performed.
[0041] As a result of the above confirmation, when "0" is recorded in the above copyright bit, it can be recognized that the copyright protection of the MP3 audio file has not been set, and the same decryption key detection process and decryption process as above are omitted, and the above The decoding program restores the compressed audio data to the original audio data, and performs an operation to output it to the audio signal processing unit 30.
[0042] Then, like the above, the decryption key is restricted from the header information of the centralized management to a player like an MP3 player equipped with the algorithm of detection and combination, and the encrypted MP3 audio file is reproduced as normal high-quality audio data. (Play) output.
[0043] The above-mentioned embodiments of the present invention are created for the purpose of prediction. The above-mentioned encryption and decryption process is completed by a variety of encryption methods like the read solo method. As an operator, you can understand this truth. Therefore, the relevant description is omitted here, and the present invention can be expanded to be applied to another compressed audio file other than the MP3 audio file.
[0044] Of course, those of ordinary skill in the art should realize that the above embodiments are only used to illustrate the present invention, but not to limit the present invention. As long as the above-mentioned implementation is within the essential spirit of the present invention, The changes and modifications of the examples will fall within the scope of the claims of the present invention.
