INFORMATION PROCESSING APPARATUS AND METHOD, AND COMPUTER PROGRAM

• US 20070033421A1
• Filed: 06/28/2006
• Published: 02/08/2007
• Est. Priority Date: 07/21/2005
• Status: Active Grant

• Current Assignee: Sony Corporation (Sony Group Corp.)
• Original Assignee: Sony Corporation (Sony Group Corp.)
• Inventors: Aoki, Yukihiko, Kawano, Shinichi, Izumi, Yuichi, Gomi, Hideho, Morita, Takao, Yukawa, Tatsuaki
• Granted Patent: US 7,886,160 B2
• Time in Patent Office: Days
• US Class Current: 713/193
• CPC Class Codes: H04L 2209/60 Digital content management, e.g. content distribution
• CPC Class Codes: H04L 63/0428 wherein the data content is protected, e.g. by encrypting or encapsulating the payload
• CPC Class Codes: H04L 63/068 using time-dependent keys, e.g. periodically changing keys cryptographic mechanisms or cryptographic arrangements for controlling usage of secret information H04L9/088
• CPC Class Codes: H04L 9/06 the encryption apparatus using shift registers or memories for block-wise or stream coding, e.g. DES systems or RC4; Hash functions; Pseudorandom sequence generators
• CPC Class Codes: H04L 9/0844 with user authentication or key authentication, e.g. ElGamal, MTI, MQV-Menezes-Qu-Vanstone protocol or Diffie-Hellman protocols using implicitly-certified keys
• CPC Class Codes: H04L 9/0891 Revocation or update of secret information, e.g. encryption key update or rekeying

Abstract

An information processing apparatus for processing encrypted data input as a byte stream with dynamically changing decryption keys includes the following elements. An encrypted data receiving section receives encrypted data input as a byte stream, identifies a range of data that is decrypted using an identical key as a unit of decryption, extracts information necessary for decryption from the byte stream, and outputs encrypted data sets in which the extracted information is added to segments of the encrypted data. An encrypted data decrypting section sequentially decrypts the encrypted data by queuing the encrypted data sets while distributing the encrypted data sets to generate plaintext data. A plaintext processing section processes the generated plaintext data.

Claims

1. An information processing apparatus for processing encrypted data input as a byte stream with dynamically changing decryption keys, the information processing apparatus comprising:

an encrypted data receiving section receiving encrypted data input as a byte stream, identifying a range of data that is decrypted using an identical key as a unit of decryption, extracting information necessary for decryption from the byte stream, and outputting encrypted data sets in which the extracted information is added to segments of the encrypted data;

an encrypted data decrypting section sequentially decrypting the encrypted data by queuing the encrypted data sets while distributing the encrypted data sets to generate plaintext data; and

a plaintext processing section processing the generated plaintext data.

2. The information processing apparatus according to claim 1, wherein the encrypted data receiving section generates the encrypted data sets by a length of the encrypted data that can be read, and segments the encrypted data sets at a key change point.

3. The information processing apparatus according to claim 1, wherein the encrypted data receiving section includes in each of the encrypted data sets the length of the original data, information indicating at which position of the encrypted data stream the segment of the encrypted data is located, and the length of the unit of decryption to which the encrypted data belongs.

4. The information processing apparatus according to claim 1, wherein the encrypted data receiving section sufficiently transfers the encrypted data sets irrespective of the progress of decryption performed by the encrypted data decrypting section.

5. An information processing method for processing encrypted data input as a byte stream with dynamically changing decryption keys, the information processing method comprising the steps of:

receiving encrypted data input as a byte stream, identifying a range of data that is decrypted using an identical key as a unit of decryption, extracting information necessary for decryption from the byte stream, and outputting encrypted data sets in which the extracted information is added to segments of the encrypted data;

sequentially decrypting the encrypted data by queuing the encrypted data sets while distributing the encrypted data sets to generate plaintext data; and

processing the generated plaintext data.

6. The information processing method according to claim 5, wherein in the step of receiving, the encrypted data sets are generated by a length of the encrypted data that can be read, and the encrypted data sets are segmented at a key change point.

7. The information processing method according to claim 5, wherein in the step of receiving, the length of original data, information indicating at which position of the encrypted data stream the segment of the encrypted data is located, and the length of the unit of decryption to which the encrypted data belongs are included in each of the encrypted data sets.

8. The information processing method according to claim 5, wherein in the step of receiving, the encrypted data sets are sufficiently transferred irrespective of the progress of decryption performed in the step of decrypting.

9. A computer-readable computer program for executing on a computer system a process for processing encrypted data input as a byte stream with dynamically changing decryption keys, the computer program causing the computer system to execute the steps of:

receiving encrypted data input as a byte stream, identifying a range of data that is decrypted using an identical key as a unit of decryption, extracting information necessary for decryption from the byte stream, and outputting encrypted data sets in which the extracted information is added to segments of the encrypted data;

sequentially decrypting the encrypted data by queuing the encrypted data sets while distributing the encrypted data sets to generate plaintext data; and

processing the generated plaintext data.