Data alteration checking apparatus and method and recording medium

• US 7,076,662 B2
• Filed: 06/22/2005
• Issued: 07/11/2006
• Est. Priority Date: 09/01/2000
• Status: Expired due to Fees

• Current Assignee: Sony Corporation (Sony Group Corp.)
• Original Assignee: Sony Corporation (Sony Group Corp.)
• Inventors: Ishizaka, Toshihiro
• Primary Examiner(s): Zand, Kambiz
• Application Number:
  US11/158,837
• Publication Number:
  US 20050246392A1
• Time in Patent Office: 384 Days
• Field of Search: 713/181
• US Class Current: 713/181
• CPC Class Codes: G06F 21/6209 to a single file or object, e.g. in a secure envelope, encrypted and accessed using a key, or with access control rules appended to the object itself
• CPC Class Codes: G06F 21/64 Protecting data integrity, e.g. using checksums, certificates or signatures
• CPC Class Codes: G06F 21/80 in storage media based on magnetic or optical technology, e.g. disks with sectors preventing unauthorised reproduction or copying of disc-type recordable media G11B20/00
• CPC Class Codes: G06F 2221/2145 Inheriting rights or properties, e.g., propagation of permissions or restrictions within a hierarchy
• CPC Class Codes: G11B 20/00086 Circuits for prevention of unauthorised reproduction or copying, e.g. piracy indicating unauthorised use of record carriers in general G11B23/28; scrambling for television signal recording H04N5/913; network architectures or network protocols for network security H04L63/00; cryptographic mechanisms or cryptographic arrangements for secret or secure communication H04L9/00
• CPC Class Codes: G11B 20/00123 the record carrier being identified by recognising some of its unique characteristics, e.g. a unique defect pattern serving as a physical signature of the record carrier
• CPC Class Codes: G11B 20/12 Formatting, e.g. arrangement of data block or words on the record carriers within interface between computers and data recorders G06F3/06
• CPC Class Codes: G11B 20/1217 on discs
• CPC Class Codes: G11B 20/1816 Testing
• CPC Class Codes: G11B 2220/2537 Optical discs
• CPC Class Codes: G11B 2220/2562 DVDs [digital versatile discs]; Digital video discs; MMCDs; HDCDs

Abstract

MAC values formed with respect to each file belonging to a directory 122A and ICVs (D-ICVc) formed on the basis of the MAC values of all files belonging to the directory 122A are stored into a sequence page 121A. Sequence pages 121A, 121B, . . . formed respectively with respect to all of directories 122A, 122B, . . . on a disk and the ICVs formed on the basis of the D-ICVs stored in all of the sequence pages 121A, 121B, . . . are stored into a sequence block 114. Since the MAC values are closed and managed every directory by the sequence pages 121A, 121B, . . . , a data alteration check can be executed every directory. An alteration check of data recorded on a recording medium can be efficiently performed.

Claims

1. Data reproducing apparatus for reproducing data recorded as files in at least one directory on a recording medium, comprising:

first arithmetic operating means for performing a first predetermined arithmetic operation on each file read from said recording medium, using inputted information serving as a key peculiar to that file, to form a first arithmetic operation value for that file;

second arithmetic operating means for performing a second predetermined arithmetic operation on each directory in which at least one of said files is bound, using the first arithmetic operation values of all of the files included in that directory, to form a second arithmetic operation value for that directory;

reading means for reading from said recording medium a file and a third arithmetic operation value corresponding to said second arithmetic operation value, said third arithmetic operation value being recorded in a predetermined area of said recording medium; and

comparing means for comparing said third arithmetic operation value and said second arithmetic operation value to detect data alteration.

2. The apparatus of claim 1, wherein said comparing means determines that a file has been altered if said second and third arithmetic operation values do not coincide.

3. The apparatus of claim 1, wherein said files are bound in a directory dependent upon file type.

4. The apparatus of claim 1, wherein said third arithmetic operation value is recorded in an area on said recording medium not accessed by a file system.

5. Data recording apparatus for recording data files in at least one directory on a recording medium, comprising:

first arithmetic operating means for performing a first predetermined arithmetic operation on each file to be recorded on said recording medium, using inputted information serving as a key peculiar to that file, to form a first arithmetic operation value;

second arithmetic operating means for performing a second predetermined arithmetic operation on each directory in which at least one of said files is bound, using the first arithmetic operation values of all of the files included in that directory, to form a second arithmetic operation value for that directory; and

recording means for recording said first and second arithmetic operation values on said recording medium.

6. The apparatus of claim 5, wherein said files are bound in a directory dependent upon file type.

7. The apparatus of claim 5, wherein said third arithmetic operation value is recorded in an area on said recording medium not accessed by a file system.

8. A data alteration checking method to discriminate whether or not data recorded as files in at least one directory on a recording medium has been altered, comprising the steps of:

performing a first predetermined arithmetic operation on each file read from said recording medium, using inputted information serving as a key peculiar to that file, to form a first arithmetic operation value for that file;

performing a second predetermined arithmetic operation on each directory in which at least one of said files is bound, using the first arithmetic operation values of all of the files included in that directory, to form a second arithmetic operation value for that directory;

comparing a third arithmetic operation value, recorded in a predetermined area of said recording medium and corresponding to said second arithmetic operation value, to said second arithmetic operation value to detect data alteration; and

determining that said file has been altered if said second and third arithmetic operation values do not coincide.

9. Data alteration checking apparatus to discriminate whether or not data recorded as files in at least one directory on a recording medium has been altered, comprising:

first arithmetic operating means for performing a first predetermined arithmetic operation on each file read from said recording medium, using inputted information serving as a key peculiar to that file, to form a first arithmetic operation value for that file;

second arithmetic operating means for performing a second predetermined arithmetic operation on each directory in which at least one of said files is bound, using the first arithmetic operation values of all of the files included in that directory, to form a second arithmetic operation value for that directory;

comparing means for comparing a third arithmetic operation value, recorded in a predetermined area of said recording medium and corresponding to said second arithmetic operation value, to said second arithmetic operation value to detect data alteration; and

means for determining that said file has been altered if said second and third arithmetic operation values do not coincide.

10. A data alteration checking system, comprising:

first arithmetic operating means for performing a first predetermined arithmetic operation on each file to be recorded on said recording medium, using inputted information serving as a key peculiar to that file, to form a first arithmetic operation value;

second arithmetic operating means for performing a second predetermined arithmetic operation on each directory in which at least one of said files is bound, using the first arithmetic operation values of all of the files included in that directory, to form a second arithmetic operation value for that directory;

recording means for recording said first and second arithmetic operation values on said recording medium;

reading means for reading said files and a third arithmetic operation value corresponding to said second arithmetic operation value from said recording medium; and

comparing means for comparing said second and third arithmetic operation values, whereby file alteration is determined when said second and third arithmetic operation values do not coincide.