Classifications

• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04K—SECRET COMMUNICATION; JAMMING OF COMMUNICATION
  • H04K1/00—Secret communication
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
  • H04L9/00—Cryptographic mechanisms or cryptographic arrangements for secret or secure communications; Network security protocols
  • H04L9/08—Key distribution or management, e.g. generation, sharing or updating, of cryptographic keys or passwords
  • H04L9/0861—Generation of secret information including derivation or calculation of cryptographic keys or passwords
  • H04L9/0872—Generation of secret information including derivation or calculation of cryptographic keys or passwords using geo-location information, e.g. location data, time, relative position or proximity to other entities
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
  • H04N1/00—Scanning, transmission or reproduction of documents or the like, e.g. facsimile transmission; Details thereof
  • H04N1/44—Secrecy systems
  • H04N1/448—Rendering the image unintelligible, e.g. scrambling
  • H04N1/4486—Rendering the image unintelligible, e.g. scrambling using digital data encryption
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
  • H04N19/00—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals
  • H04N19/60—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using transform coding
  • H04N19/63—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using transform coding using sub-band based transform, e.g. wavelets
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
  • H04N21/00—Selective content distribution, e.g. interactive television or video on demand [VOD]
  • H04N21/20—Servers specifically adapted for the distribution of content, e.g. VOD servers; Operations thereof
  • H04N21/23—Processing of content or additional data; Elementary server operations; Server middleware
  • H04N21/234—Processing of video elementary streams, e.g. splicing of video streams or manipulating encoded video stream scene graphs
  • H04N21/2347—Processing of video elementary streams, e.g. splicing of video streams or manipulating encoded video stream scene graphs involving video stream encryption
  • H04N21/23476—Processing of video elementary streams, e.g. splicing of video streams or manipulating encoded video stream scene graphs involving video stream encryption by partially encrypting, e.g. encrypting the ending portion of a movie
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
  • H04N21/00—Selective content distribution, e.g. interactive television or video on demand [VOD]
  • H04N21/20—Servers specifically adapted for the distribution of content, e.g. VOD servers; Operations thereof
  • H04N21/25—Management operations performed by the server for facilitating the content distribution or administrating data related to end-users or client devices, e.g. end-user or client device authentication, learning user preferences for recommending movies
  • H04N21/266—Channel or content management, e.g. generation and management of keys and entitlement messages in a conditional access system, merging a VOD unicast channel into a multicast channel
  • H04N21/26613—Channel or content management, e.g. generation and management of keys and entitlement messages in a conditional access system, merging a VOD unicast channel into a multicast channel for generating or managing keys in general
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
  • H04N21/00—Selective content distribution, e.g. interactive television or video on demand [VOD]
  • H04N21/40—Client devices specifically adapted for the reception of or interaction with content, e.g. set-top-box [STB]; Operations thereof
  • H04N21/43—Processing of content or additional data, e.g. demultiplexing additional data from a digital video stream; Elementary client operations, e.g. monitoring of home network or synchronising decoder's clock; Client middleware
  • H04N21/44—Processing of video elementary streams, e.g. splicing a video clip retrieved from local storage with an incoming video stream or rendering scenes according to encoded video stream scene graphs
  • H04N21/4405—Processing of video elementary streams, e.g. splicing a video clip retrieved from local storage with an incoming video stream or rendering scenes according to encoded video stream scene graphs involving video stream decryption
  • H04N21/44055—Processing of video elementary streams, e.g. splicing a video clip retrieved from local storage with an incoming video stream or rendering scenes according to encoded video stream scene graphs involving video stream decryption by partially decrypting, e.g. decrypting a video stream that has been partially encrypted

Definitions

• Fig. 2 is a block diagram showing the functional arrangement of an image encoding unit 11;
• Fig. 5B is a schematic view showing the format of a code sequence
• Fig. 9 shows an example of keys and key IDs corresponding to respective tiles and respective resolution levels of each tile when an image is made up of four tiles, tile 01 is made up of three resolution levels, tile 02 is made up of two resolution levels, tile 03 is made up of three resolution levels, and tile 04 is made up of four resolution levels;
• Fig. 16 is a flow chart showing a process executed by a code sequence decryption unit 124 according to the third embodiment of the present invention.
• Fig. 23A shows an example of a code sequence
• Fig. 23B shows correspondence between respective subbands and the sizes of tiles to be displayed
• Figs. 5A, 5B, 5C, and 5D show the format of the code sequence which is generated and output in this way.
• Fig. 5A shows the overall format of the code sequence, in which MH is a main header; TH, a tile header; and BS, a bitstream.
• Bitstream key K_BS is generated from image key K_I using the encoding parameters P (step S72) .
• bitstream key K_BS is generated using:
• K_Ti H(K_BS I I i) (8)
• K__TiSj H(K_TiSj - 1) (9)
• the generated resolution key K_TiSj is saved together with a key ID which is also generated in step S76.
• Fig. 8 is a view for explaining an example of the key ID generation method. As shown in Fig. 8, the key ID of this embodiment is formed to have a tile index in the former half, and a resolution index in the latter half.
• image key K_IMG may have a key ID "0000”
• bitstream key K_BS may have a key ID "0001”
• respective tile keys may have key IDs "0100”, "0200”, “0300”,....
• each tile key is equal to a resolution key of the highest resolution in each tile (for example, in case of tile 1, K_T1 and K_T1S1) , the tile key or the resolution key of the highest resolution may be omitted.
• the keys and key IDs have been independently explained for the sake of simplicity. However, in practice, pairs of keys and key IDs in this embodiment can be handled as keys required for decryption.
• the code sequence encryption processing unit 13 receives the code sequence, keys generated by the previous key generation process, and ID reference table.
• the unit 13 executes an encryption process of the code sequence using the keys and ID reference table, and outputs an encrypted code sequence. More specifically, the location of a bitstream to be encrypted in the code sequence is specified using a key ID corresponding to that bitstream and the ID reference table, and the bitstream located at the specified location is encrypted. For example, a bitstream corresponding to resolution level 2 of tile 1 is encrypted using a key paired with a key ID "0102" . Note that the code sequence encryption processing unit 13 does not use image key K_IMG, bitstream key K_BS, and tile keys.
• the first key generation unit 121 need not always generate all the keys and key IDs unlike in the key generation process that has been explained using Fig. 6, and need only generate a key and key ID corresponding to a bitstream to be decrypted by the code sequence decryption unit 124 (to be described later) .
• key K_Si of resolution i is generated from bitstream key K_BS (step S144) .
• key K_Si is generated by:
• K_TjSi of tile j is generated from key K_Si of resolution i (step S146) .
• key K_TjSi is generated by:
• step S147 The generated tile key K_TjSi is saved together with a key ID which is also generated in step S146. It is then checked if variable j ⁇ parameter M_i (step S147) .
• parameter M i is the total number of tiles. That is, it is determined whether or not tile keys K_TjSi corresponding to all tiles of resolution i have been generated. If the checking result is true, the flow advances to step S148 to increment variable j by 1 (step S148), and the process in step S146 is executed. On the other hand, if the checking result in step S147 is false, the flow advances to step S149 to check if variable i ⁇ parameter N (step S149) . Note that parameter N is the number of resolution levels.
• the encryption process is executed using different keys for respective tiles or resolution levels of a code sequence.
• decryption control for each resolution level or each tile can be implemented.
• the present invention is not limited to such specific process, and predetermined bitstreams in a code sequence may be encrypted using only one encryption key.
• variable i is initialized to zero.
• a bitstream designated by variable i is encrypted (step S173) .
• a record of the bitstream designated by variable i in the encryption map is erased (step S174). However, if the decryption process is not normally terminated due to, e.g., use of a wrong key or the like, the record of this bitstream may be left unerased.
• the decryption process can be executed while preventing double decryption.
• reference numeral 181 denotes a part of a code sequence, and one rectangle indicates one packet. Also, hatched packets indicate encrypted ones.
• reference numeral 182 denotes an example of an encryption map corresponding to the code sequence 181. As shown in Figs. 17A and 17B, one rectangle in the map 182 corresponds to one packet, and a bit value is assigned to each packet. When a packet is encrypted, a bit value "1" is assigned; when a packet is not encrypted, "0" is assigned.
• the encryption map shown in Fig. 17B is generated in the encryption process as in that of the third embodiment.
• an already decrypted portion can be prevented from being decrypted again (double decryption) .
• double decryption often disturbs normal image decryption even when a correct key is used.
• the aforementioned double decryption prevention technique is effective in such case.
• an already encrypted portion can be prevented from being encrypted again (double encryption) .
• the decryption apparatus comprises the first key generation unit 191, second key generation unit 193, code sequence decryption unit 194, control unit 195, and image decoding unit 196.
• the first key generation unit 191, network unit 192, second key generation unit 193, code sequence decryption unit 194, and image decoding unit 196 in Fig. 18 make the same operations as those of the first key generation unit 121, network unit 122, second key generation unit 123, code sequence decryption unit 124, and image decoding unit 125, and a description thereof will be omitted.
• the control unit 195 will be described below.
• Fig. 19 is a block diagram showing the functional arrangement of the control unit 195 according to this embodiment. As shown in Fig.
• the control unit 195 comprises a determination unit 201 and output unit 202.
• the determination unit 201 receives the ID reference table or encryption map, speci ies encrypted bitstreams or packets using the ID reference table or encryption map, and outputs information associated with the determined bitstreams or packets. If the ID reference table or encryption map is encrypted, the determination unit 201 decrypts it. Alternatively, if the ID reference table or encryption map has undergone the signature process, the determination unit 201 executes a signature verification process. If a signature cannot be normally verified, the process ends.
• the present invention can facilitate management of keys used in encryption.

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• Engineering & Computer Science (AREA)
• Signal Processing (AREA)
• Multimedia (AREA)
• Computer Networks & Wireless Communication (AREA)
• Computer Security & Cryptography (AREA)
• Databases & Information Systems (AREA)
• Compression Of Band Width Or Redundancy In Fax (AREA)
• Compression Or Coding Systems Of Tv Signals (AREA)
• Facsimile Transmission Control (AREA)

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• 2002
  • 2002-06-28 JP JP2002191284A patent/JP4181802B2/ja not_active Expired - Fee Related
• 2003
  • 2003-06-24 AU AU2003243006A patent/AU2003243006A1/en not_active Abandoned
  • 2003-06-24 CN CNB03814879XA patent/CN100456668C/zh not_active Expired - Fee Related
  • 2003-06-24 EP EP20030761785 patent/EP1518348B1/en not_active Expired - Lifetime
  • 2003-06-24 WO PCT/JP2003/007976 patent/WO2004004198A1/en not_active Ceased
• 2004
  • 2004-10-18 US US10/965,874 patent/US7447314B2/en not_active Expired - Fee Related

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