ClassID:

198709

G11B20/00492 - CPC Classification

Classification description:

Signal processing not specific to the method of recording or reproducing; Circuits therefor; Circuits for prevention of unauthorised reproduction or copying, e.g. piracy involving encryption or decryption of contents recorded on or reproduced from a record carrier characterised by a specific kind of data which is encrypted and recorded on and/or reproduced from the record carrier wherein content or user data is encrypted

Sub-classes:
Recent Application in this class:
#1
20200013431
2020-01-09

INFORMATION PROCESSING APPARATUS, INFORMATION RECORDING MEDIUM, INFORMATION PROCESSING METHOD, AND PROGRAM

#2
20180239879
2018-08-23

Information processing device and information processing method

#3
20180069696
2018-03-08

ENCRYPTED DATA MANAGEMENT METHOD AND DEVICE

#4
20160155466
2016-06-02

Information processing device, information recording medium, information processing method, and program

#5
20160155465
2016-06-02

Video masking processing method and apparatus

#6
20160125917
2016-05-05

System, method, and apparatus for embedding personal video recording functions at picture level

#7
20150381359
2015-12-31

Enciphering apparatus and method, deciphering apparatus and method as well as information processing apparatus and method

#8
20150287432
2015-10-08

Server device, playback device and content distribution system

#9
20150071610
2015-03-12

Systems and methods for content playback and recording

#10
20140149661
2014-05-29

Information carrier comprising access information

#11
20140075195
2014-03-13

Protection of content based on encryption

#12
20140040634
2014-02-06

Recording device, and content-data playback system

#13
20130236009
2013-09-12

Enciphering apparatus and method, deciphering apparatus and method as well as information processing apparatus and method

#14
20130067241
2013-03-14

CONTENTS DATA UTILIZATION SYSTEM AND METHOD, AND MOBILE COMMUNICATION TERMINAL USED FOR THE SAME

#15
20130039492
2013-02-14

Content receiving terminal, content exporting and reproducing method, and recording medium

#16
20130039485
2013-02-14

INFORMATION PROCESSING SYSTEM, REPRODUCING DEVICE, INFORMATION PROCESSING DEVICE, INFORMATION PROCESSING METHOD, AND PROGRAM

#17
20130013624
2013-01-10

Reducing errors in sending file attachments

#18
20120257744
2012-10-11

Enciphering apparatus and method, deciphering apparatus and method as well as information processing apparatus and method

#19
20120224696
2012-09-06

Interoperable digital rights management

#20
20120210140
2012-08-16

Information processing apparatus, information recording medium manufacturing apparatus, and information recording medium

#21
20120189279
2012-07-26

METHOD FOR CONTROLLING CONTENT REPRODUCING APPARATUS AND NON-TRANSITORY COMPUTER READABLE MEDIUM STORING PROGRAM FOR CAUSING COMPUTER TO IMPLEMENT METHOD

#22
20120173799
2012-07-05

Data storage apparatus, information processing apparatus, information processing method, and program

#23
20120141093
2012-06-07

Content transmission/reception system

#24
20120134249
2012-05-31

Method for copy protection

#25
20120113788
2012-05-10

Information carrier comprising access information

#26
20120106932
2012-05-03

Reconciling digital content at a digital media device

#27
20120102102
2012-04-26

Content providing device, data processing method, and computer program

#28
20120079610
2012-03-29

Content management program, method and device

#29
20120056001
2012-03-08

Optical disc

#30
20120054488
2012-03-01

Content processing apparatus and encryption processing method

#31
20120020474
2012-01-26

RECORDING DEVICE, CONTROLLER, CONTROL METHOD OF RECORDING DEVICE

#32
20110286315
2011-11-24

Optical disk, an optical disk barcode forming method, an optical disk reproduction apparatus, a marking forming apparatus, a method of forming a laser marking on an optical disk, and a method of manufacturing an optical disk

#33
20110276809
2011-11-10

Method of storing data in a memory device and a processing device for processing such data

#34
20110145599
2011-06-16

Data stream filters and plug-ins for storage managers

#35
20110126279
2011-05-26

Information processing apparatus, software installing method, and recording medium

#36
20110113350
2011-05-12

METHOD, SYSTEM AND PROGRAM PRODUCT FOR BUILDING COLLABORATION APPLICATIONS USING MULTIPLE-PEER USER INTERFACE LIBRARIES

#37
20110110517
2011-05-12

Content playback device

#38
20110107111
2011-05-05

Information carrier comprising access information and dummy information

#39
20110035423
2011-02-10

Reproducing apparatus, reproducing method, program, program storage medium, data delivery system, data structure, and manufacturing method of recording medium

#40
20110026713
2011-02-03

Efficient rebinding of partitioned content encrypted using broadcast encryption

#41
20110016181
2011-01-20

Reducing errors in sending file attachments

#42
20100313034
2010-12-09

INFORMATION PROCESSING APPARATUS, DATA RECORDING SYSTEM, INFORMATION PROCESSING METHOD, AND PROGRAM

#43
20100310075
2010-12-09

Method and system for content replication control

#44
20100290619
2010-11-18

Enciphering apparatus and method, deciphering apparatus and method as well as information processing apparatus and method

#45
20100268953
2010-10-21

Recording device, and content-data playback system

#46
20100241863
2010-09-23

DEVICE FOR REPRODUCING DIGITAL CONTENT, SECURE ELECTRONIC ENTITY, SYSTEM COMPRISING SAID ELEMENTS AND METHOD FOR REPRODUCING DIGITAL CONTENT

#47
20100235633
2010-09-16

Authentication and encryption utilizing command identifiers

#48
20100223477
2010-09-02

CONTENT REPRODUCING DEVICE, CONTENT REPRODUCING METHOD, RECORDING MEDIUM, AND INTEGRATED CIRCUIT

#49
20100202277
2010-08-12

Information recording method and apparatus, information recording medium, and information recording medium manufacturing method and apparatus

#50
20100199103
2010-08-05

Secure storage

#51
20100195973
2010-08-05

Video data reproducing apparatus and method utilizing acquired data structure including video data and related reproduction information, non-transitory recording medium containing the data structure and non-transitory recording medium storing control program for causing computer to operate as reproducing apparatus

#52
20100195971
2010-08-05

Reproducing apparatus, method for operating reproducing apparatus and non-transitory computer-readable recording medium storing control program

#53
20100189424
2010-07-29

Apparatus and method for processing and reading a file having a media data container and a metadata container

#54
20100189414
2010-07-29

Reproducing apparatus, method for controlling reproducing apparatus, content recording medium, and non-transitory recording medium storing control program

#55
20100189407
2010-07-29

Method and apparatus for reproducing content data, non-transitory computer-readable medium for causing the apparatus to carry out the method, and non-transitory content recording medium for causing the apparatus to carry out the method

#56
20100189406
2010-07-29

Video data reproducing apparatus and method utilizing acquired data structure including video data and related reproduction information, and non-transitory recording medium storing control program for causing computer to operate as reproducing apparatus

#57
20100189256
2010-07-29

Apparatus and method for storing and reading a file having a media data container and metadata container

#58
20100174917
2010-07-08

INFORMATION RECORDING MEDIUM, REPRODUCING APPARATUS AND CUMPUTER PROGRAM

#59
20100153743
2010-06-17

ELECTRONIC DEVICE AND METHOD TO CONTROL OUTPUT THEREOF

#60
20100131767
2010-05-27

Methods for audio watermarking and decoding

#61
20100031061
2010-02-04

Data storage device and management method of cryptographic key thereof

#62
20100027797
2010-02-04

Playing Apparatus and Management Method

#63
20100021125
2010-01-28

METHODS AND APPARATUS FOR CREATION, DISTRIBUTION AND PRESENTATION OF POLYMORPHIC MEDIA

#64
20100005301
2010-01-07

Authentication and encryption utilizing command identifiers

#65
20100005109
2010-01-07

Memory controller, nonvolatile storage device, and nonvolatile storage device system

#66
20090319807
2009-12-24

Systems and methods for content playback and recording

#67
20090316888
2009-12-24

Playing method and device of digital right managing multimedia

#68
20090290710
2009-11-26

UNLOCKING A PROTECTED PORTABLE STORAGE MEDIUM

#69
20090274026
2009-11-05

Optical storage medium, information recording apparatus, and information reproducing apparatus

#70
20090271319
2009-10-29

Embedded Licenses for Content

#71
20090268598
2009-10-29

Optical storage medium, information recording apparatus, and information reproducing apparatus

#72
20090268590
2009-10-29

OPTICAL STORAGE MEDIUM, INFORMATION RECORDING APPARATUS, AND INFORMATION REPRODUCING APPARATUS

#73
20090240957
2009-09-24

COPY PROTECTION METHOD, CONTENT PLAYBACK APPARATUS, AND IC CHIP

#74
20090238362
2009-09-24

Disc manufacturing method, data recording apparatus, information recording medium, information processing apparatus and method, and computer program

#75
20090232312
2009-09-17

ENCRYPTED CONTENT REPRODUCTION DEVICE, ENCRYPTED CONTENT REPRODUCTION METHOD, PROGRAM, AND RECORDING MEDIUM FOR STORING THE PROGRAM

#76
20090231967
2009-09-17

RENDERING PRE-RECORDED AND ADDITIONAL CONTENT

#77
20090214042
2009-08-27

Content playback apparatus, content playback method, computer program, key relay apparatus, and recording medium

#78
20090204825
2009-08-13

Information processing apparatus and method, information recording medium, and computer program

#79
20090168619
2009-07-02

Optical disk, an optical disk barcode forming method, an optical disk reproduction apparatus, a marking forming apparatus, a method of forming a laser marking on an optical disk, and a method of manufacturing an optical disk

#80
20090168110
2009-07-02

Content Transmitting Apparatus, Content Receiving Apparatus, and Content Transmitting Method

#81
20090150666
2009-06-11

Information processing apparatus and license distribution system

#82
20090138726
2009-05-28

Authentication-secured access to a data carrier comprising a mass storage device and chip

#83
20090136207
2009-05-28

AV DATA TRANSMITTING APPARATUS AND AV DATA RECEIVING APPARATUS

#84
20090119514
2009-05-07

CONTENT DATA STRUCTURE AND MEMORY CARD

#85
20090113556
2009-04-30

Disk protection system

#86
20090105859
2009-04-23

Playback program

#87
20090100273
2009-04-16

Prevent data storage device circuitry swap

#88
20090097644
2009-04-16

Playback apparatus and playback control method

#89
20090097372
2009-04-16

Content data recording/reproducing device

#90
20090094321
2009-04-09

Content providing device, data processing method, and computer program

#91
20090086614
2009-04-02

Optical disc on which information is written on a block-by-block basis

#92
20090086589
2009-04-02

Optical disk having wobble patterns representing control information

#93
20090080664
2009-03-26

Method of storing broadcast contents in mobile broadcast service terminal

#94
20090080296
2009-03-26

Optical disc

#95
20090070600
2009-03-12

Method for etching and secure distribution of digital data, access device and writer

#96
20090070584
2009-03-12

Method for Providing, Distributing and Engraving Digital Data and Associated Distribution Server

#97
20090059751
2009-03-05

OPTICAL DISC APPARATUS AND DATA RECORDING/REPRODUCING APPARATUS

#98
20090052670
2009-02-26

METHOD AND APPARATUS FOR STORING DIGITAL CONTENT IN STORAGE DEVICE

#99
20090052314
2009-02-26

Recording medium with optional information and apparatus and methods for forming, recording, reproducing and controlling reproduction of the recording medium

#100
20090052290
2009-02-26

Optical disk device and method for processing optical disk

#101
20090041248
2009-02-12

Recording medium, authoring device, and authoring method

#102
20090037748
2009-02-05

Method and apparatus for forbidding use of digital content against copy control information

#103
20090022320
2009-01-22

Content copying device and content copying method

#104
20090013195
2009-01-08

Data storing method, data playback method, data recording device, data playback device, and recording medium

#105
20090003608
2009-01-01

Block-level storage device with content security

#106
20090003143
2009-01-01

Recording Medium, Recording/Reproduction Apparatus and Replay Apparatus

#107
20080310638
2008-12-18

Storage Medium Processing Method, Storage Medium Processing Device, and Program

#108
20080310292
2008-12-18

OPTICAL DISK, OPTICAL DISK RECORDING AND REPRODUCING APPARATUS, METHOD FOR RECORDING, REPRODUCING AND DELETING DATA ON OPTICAL DISK, AND INFORMATION PROCESSING SYSTEM

#109
20080304401
2008-12-11

INFORMATION RECORDING MEDIUM, INFORMATION RECORDING METHOD, AND INFORMATION REPRODUCING METHOD

#110
20080294908
2008-11-27

Recording Device, Content Key Processing Device, Recording Medium, and Recording Method

#111
20080279532
2008-11-13

Recording and reproducing apparatus

#112
20080270796
2008-10-30

System and method for providing program information, and recording medium used therefor

#113
20080247548
2008-10-09

Content processing apparatus and encryption processing method

#114
20080244698
2008-10-02

Authorized content verification method, content transmission/reception system, transmitter, and receiver

#115
20080243979
2008-10-02

Data stream filters and plug-ins for storage managers

#116
20080226067
2008-09-18

Method and Circuit for Encrypting a Data Stream

#117
20080210747
2008-09-04

Information processing apparatus, information recording medium manufacturing apparatus, and information recording medium

#118
20080152317
2008-06-26

Information recording/reproduction device and information recording medium

#119
20080149700
2008-06-26

Speckle Pattern For Authenticating An Information Carrier

#120
20080141039
2008-06-12

SYSTEM FOR USING A VIRTUAL TAPE ENCRYPTION FORMAT

#121
20080133932
2008-06-05

Portable data support with watermark function

#122
20080130885
2008-06-05

Reproducing device, recording device, recording medium, data processing method, data processing program, data recording method, data recording program, and integrated circuit

#123
20080123481
2008-05-29

Method for Saving ther Keylockers on Optical Discs

#124
20080121701
2008-05-29

MULTIMEDIA GENERATION SYSTEM AND METHOD FOR BIOMETRIC EMBEDDED DIGITAL MULTIMEDIA DATA

#125
20080114992
2008-05-15

Interoperable digital rights management

#126
20080075284
2008-03-27

Public key media key block

#127
20080049936
2008-02-28

Optical Disc Signal Processing Circuit

#128
20080049933
2008-02-28

Information Recording Medium

#129
20080044017
2008-02-21

Copyright protection system, recording device, and reproduction device

#130
20080043607
2008-02-21

Recording medium with intermittent or alternate wobbled pits and apparatus and methods for forming, recording, and reproducing the recording medium

#131
20080016342
2008-01-17

Recording medium, content player, content player method, and computer program

#132
20080013723
2008-01-17

Enciphering apparatus and method, deciphering apparatus and method as well as information processing apparatus and method

#133
20070300078
2007-12-27

Recording medium, and device and method for recording information on recording medium

#134
20070276756
2007-11-29

Recording/Reproducing Device, Recording Medium Processing Device, Reproducing Device, Recording Medium, Contents Recording/Reproducing System, And Contents Recording/Reproducing Method

#135
20070260742
2007-11-08

Media Storage and distribution in a Local Area Network

#136
20070245402
2007-10-18

Method and apparatus of recording information on and reproducing information from a recording medium

#137
20070230309
2007-10-04

Information Recording Medium

#138
20070226399
2007-09-27

Recording medium, and information processing device and information processing method for the recording medium

#139
20070223705
2007-09-27

Storage Medium Processing Method, Storage Medium Processing Apparatus, and Program

#140
20070220194
2007-09-20

SYSTEM FOR COVERTLY STORING CONTROL INFORMATION

#141
20070211901
2007-09-13

APPARATUS, METHOD, AND COMPUTER PROGRAM PRODUCT FOR RECORDING CONTENTS

#142
20070201511
2007-08-30

RELAY DEVICE AND COMMUNICATION DEVICE REALIZING CONTENTS PROTECTION PROCEDURE OVER NETWORKS

#143
20070198424
2007-08-23

Content playback device

#144
20070194117
2007-08-23

Information processing apparatus, information recording medium, information processing method, and computer program

#145
20070189718
2007-08-16

Reproduction device and reproduction method, program and program storage medium, data distribution system, data structure, and method for manufacturing recording medium

#146
20070168838
2007-07-19

Reproduction apparatus and method for reproducing a unique medium identifier

#147
20070159329
2007-07-12

Information protection using a printed electronic circuit and laser impression

#148
20070140484
2007-06-21

Enciphering apparatus and method, deciphering apparatus and method as well as information processing apparatus and method

#149
20070136612
2007-06-14

Data processing apparatus and data processing method

#150
20070136282
2007-06-14

Information processing apparatus and method, information recording medium, and computer program

#151
20070124603
2007-05-31

Content reproduction system

#152
20070124250
2007-05-31

Content management program, method and device

#153
20070116280
2007-05-24

Information processing apparatus and method, information recording medium manufacturing apparatus and method, and information recording medium

#154
20070112685
2007-05-17

Contents distribution system, recording apparatus, signature apparatus, contents supply apparatus, and contents playback apparatus

#155
20070104054
2007-05-10

Information processing apparatus including a communication unit that communicates with an IC chip and associated methodology

#156
20070100767
2007-05-03

Method and system for providing DRM license

#157
20070100764
2007-05-03

Method and system for providing DRM license

#158
20070100763
2007-05-03

Method and system for providing DRM license

#159
20070094505
2007-04-26

Content recording/reproducing system, distribution device, reproducing device, and recording device

#160
20070094309
2007-04-26

Data transfer device

#161
20070092078
2007-04-26

RECORDING APPARATUS, REPRODUCTION APPARATUS, DATA PROCESSING APPARATUS, RECORDING AND REPRODUCTION APPARATUS AND DATA TRANSMISSION APPARATUS AND CORRESPONDING METHODS

#162
20070092077
2007-04-26

Recording apparatus, reproduction apparatus, data processing apparatus, recording and reproduction apparatus and data transmission apparatus and corresponding methods

#163
20070088961
2007-04-19

Data processing apparatus and data processing method

#164
20070083772
2007-04-12

Digital work protection system, record/playback device, recording medium device, and model change device

#165
20070081432
2007-04-12

Optical disk having wobble patterns representing control information

#166
20070053659
2007-03-08

Content reproducing apparatus, recording medium, content recording medium, and method for controlling content reproducing apparatus

#167
20070050821
2007-03-01

Image commercial transactions system and method, image transfer system and method, image distribution system and method,display device and method

#168
20060294013
2006-12-28

Image commercial transactions system and method, image transfer system and method, image distribution system and method, display device and method

#169
20060282898
2006-12-14

Copyright protection system, key generation apparatus, recording apparatus, reproduction apparatus, read-out apparatus, decryption apparatus, recording medium, recording method and program

#170
20060282696
2006-12-14

Storage and access control method for storage

#171
20060277415
2006-12-07

Content protection method and system

#172
20060257102
2006-11-16

Method and apparatus for managing contents

#173
20060254408
2006-11-16

Recording control method

#174
20060239462
2006-10-26

Record carrier comprising encryption indication information

#175
20060215996
2006-09-28

System, method, and apparatus for embedding personal video recording functions at picture level

#176
20060215295
2006-09-28

Recording media, recording and reproducing apparatus, and method for recording and reproducing

#177
20060204210
2006-09-14

Content data recording apparatus with encryption by media ID

#178
20060195908
2006-08-31

Data processing circuit, reproduction apparatus, data processing method, reproduction method, storage medium in which data processing program is stored, and storage medium in which reproduction program is stored

#179
20060178995
2006-08-10

Secure pre-recorded digital medium

#180
20060164944
2006-07-27

Recording medium with copy protection information formed in intermittent or alternate wobbled pits and apparatus and methods for forming, recording, and reproducing the recording medium

#181
20060156038
2006-07-13

Recording medium with copy protection indicating information and apparatus and methods for forming, recording, reproducing and restricting reproduction of the recording medium

#182
20060143481
2006-06-29

System, method, and apparatus for securely providing content viewable on a secure device

#183
20060143480
2006-06-29

Method of managing copy protection information of a recording medium, recording medium with copy protection information for contents recorded thereon, and reproducing method for the recording medium

#184
20060143478
2006-06-29

Controller to move contents and control method thereof

#185
20060140402
2006-06-29

Enciphering apparatus and method, deciphering apparatus and method as well as information processing apparatus and method

#186
20060133646
2006-06-22

Video steganography

#187
20060131407
2006-06-22

Optical disk, an optical disk barcode forming method, an optical disk reproduction apparatus, a marking forming apparatus, a method of forming a laser marking on an optical disk, and a method of manufacturing an optical disk

#188
20060129514
2006-06-15

Information terminal and content storage/playback method

#189
20060114787
2006-06-01

Simultaneous playback and persistent storage of digital media content

#190
20060112284
2006-05-25

Copyright management method, information recording/reproducing method and device, and information recording medium and method of manufacturing the medium

#191
20060109984
2006-05-25

Methods for audio watermarking and decoding

#192
20060104449
2006-05-18

Record carrier with distributed decryption information

#193
20060077812
2006-04-13

Player/recorder, contents playing back method and contents recording method

#194
20060071824
2006-04-06

Multi-streaming apparatus and multi-streaming method using temporary storage medium

#195
20060067529
2006-03-30

Content management method and recording medium

#196
20060064601
2006-03-23

Information carrier comprising access information and dummy information

#197
20060041510
2006-02-23

Method for a secure system of content distribution for DVD applications

#198
20060005257
2006-01-05

Encrypted contents recording medium and apparatus and method for reproducing encrypted contents

#199
20060004666
2006-01-05

Image commercial transactions system and method, image transfer system and method, image distribution system and method, display device and method

#200
20050287987
2005-12-29

Contents data utilization system and method, and mobile communication terminal used for the same

#201
20050286379
2005-12-29

System, method, and computer program for verifying data on information recording medium

#202
20050276576
2005-12-15

Content recording medium, method of obtaining playback-permission information, content playback method, and content playback apparatus

#203
20050246372
2005-11-03

Temporary accumulation management device

#204
20050244003
2005-11-03

Modulator, modulation method, and method of manufacturing an optical recordable medium with enhanced security for confidential information

#205
20050238324
2005-10-27

Recording medium and production method, playback method, and playback device thereof

#206
20050220303
2005-10-06

Recording data recording method, recording data reproduction method, recording device, reproduction device, and multi-layered optical recording medium

#207
20050210277
2005-09-22

Information recording medium, information processing apparatus, information processing method, and computer program

#208
20050209971
2005-09-22

Method of managing copy protection information of a recording medium, recording medium with copy protection information for contents recorded thereon, and reproducing method for the recording medium

#209
20050209968
2005-09-22

Method and apparatus for transmitting and receiving a decoding key encoded with specific information to decode encrypted information of a record medium

#210
20050198529
2005-09-08

Information processing apparatus, authentication processing method, and computer program

#211
20050192903
2005-09-01

Method and apparatus for transmitting and receiving a decoding key encoded with specific information to decode encrypted information of a record medium

#212
20050185547
2005-08-25

Optical disk, optical disk recording and reproducing apparatus, method for recording, reproducing and deleting data on optical disk, and information processing system

#213
20050180573
2005-08-18

Access control for digital content

#214
20050177259
2005-08-11

Method and apparatus for transmitting and receiving a decoding key encoded with specific information to decode encrypted information of a record medium

#215
20050177258
2005-08-11

Method and apparatus for transmitting and receiving a decoding key encoded with specific information to decode encrypted information of a record medium

#216
20050169118
2005-08-04

Method of recording and/or reproducing data under control of domain management system

#217
20050165702
2005-07-28

Method and apparatus for transmitting and receiving a decoding key encoded with specific information to decode encrypted information of a record medium

#218
20050165701
2005-07-28

Method and apparatus for transmitting and receiving a decoding key encoded with specific information to decode encrypted information of a record medium

#219
20050160053
2005-07-21

Semiconductor memory card that records contents for trial and purchase, and recording apparatus, recording and reproducing apparatus, and sales method for the same

#220
20050154682
2005-07-14

Secure transfer of content to writable media

#221
20050144478
2005-06-30

Content receiving/storing apparatus and content delivery system

#222
20050123136
2005-06-09

Motion picture file encryption method and digital rights management method using the same

#223
20050108560
2005-05-19

Method of copying and decrypting encrypted digital data and apparatus therefor

#224
20050102506
2005-05-12

Anti-piracy system

#225
20050091491
2005-04-28

Block-level storage device with content security

#226
20050084251
2005-04-21

Digital content reproducing apparatus and method for reproducing digital content

#227
20050078825
2005-04-14

Encryption apparatus, decryption apparatus, secret key generation apparatus, and copyright protection system

#228
20050031156
2005-02-10

Video steganography

#229
20050025316
2005-02-03

Access control for digital content

#230
20050018854
2005-01-27

Content playback apparatus, content playback method, and program

#231
20050005141
2005-01-06

Information recording medium, information processing apparatus, information processing method, and computer program