Information sending system and method for sending encrypted information

• US 6,381,331 B1
• Filed: 10/05/1998
• Issued: 04/30/2002
• Est. Priority Date: 10/06/1997
• Status: Expired due to Fees

• Current Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Original Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Inventors: Kato, Takehisa
• Primary Examiner(s): Peeso, Thomas R.
• Application Number:
  US09/166,285
• Time in Patent Office: 1,303 Days
• Field of Search: 380/28, 380/29, 380/259, 380/277, 380/37, 713/168, 713/200
• US Class Current: 380/37
• CPC Class Codes: H04L 2209/56 Financial cryptography, e.g. electronic payment or e-cash
• CPC Class Codes: H04L 2209/60 Digital content management, e.g. content distribution
• CPC Class Codes: H04L 63/0442 wherein the sending and receiving network entities apply asymmetric encryption, i.e. different keys for encryption and decryption cryptographic mechanisms or cryptographic arrangements for public-key encryption H04L9/30
• CPC Class Codes: H04L 9/0825 using asymmetric-key encryption or public key infrastructure [PKI], e.g. key signature or public key certificates

Abstract

This invention discloses an information sending system for sending encrypted information which can be decrypted in units of parts of information. This information sending system includes information segmentation means for segmenting information into a plurality of blocks, first encryption means for encrypting more than one blocks of the plurality of blocks using a first key, second encryption means for encrypting more than one blocks of the blocks other than those encrypted by the first encryption means using a second key, and information sending means for sending outgoing information including the blocks encrypted by the first encryption means and those encrypted by the second encryption means.

Claims

1. An information sending system comprising:

an information segmenter configured to segment information into a plurality of blocks;

a first encoder configured to encrypt more than one block of the plurality of blocks using a first key;

a second encoder configured to encrypt more than one block of the plurality of blocks other than the blocks encrypted by said first encoder using a second key; and

an information sender configured to send outgoing information including the blocks encrypted by said first encoder and the blocks encrypted by said second encoder to a first receiver, and to send outgoing information including the blocks encrypted by said first encoder to a second receiver, wherein the first receiver being able to decrypt the blocks of the plurality of blocks encrypted by the first key and the blocks of the plurality of blocks encrypted by the second key using the first and second keys in order to understand a meaning of the information, and a second receiver being able to decrypt the blocks of the plurality of blocks encrypted by the first key using the first key in order to check the blocks encrypted by the first key.

2. A system according to claim 1, further comprising:

an identification information appending means for appending, to the outgoing information, identification information indicating the blocks encrypted by said first encoder and the blocks encrypted by said second encoder of the blocks contained in the outgoing information.

3. A system according to claim 2, further comprising:

a key information appending means for appending, to the outgoing information, the encrypted first key, and the second key encrypted by an encryption key different from a key used for encrypting the first key.

4. A system according to claim 3, further comprising:

an outgoing information auditing means for auditing contents of outgoing information to be sent by said information sending means,

said outgoing information auditing means including;

a key decoder for decrypting the encrypted first key appended by said key information appending means;

a block decoder for decrypting the blocks encrypted by said first encoder on the basis of the first key decrypted by said key decoder, and the identification information; and

an output means for outputting the blocks decrypted by said block decoder.

5. A system according to claim 4, wherein said outgoing information auditing means further includes:

an identification information passing means for passing the identification information to said first and second encoder upon encrypting the information to be segmented by said information segmentation means.

6. A system according to claim 3, further comprising:

a contents database for storing a plurality of kinds of information to be segmented by said information segmentation means.

7. A system according to claim 6, further comprising:

a user database for the registering the presence/absence of authority that allows reception of information in said contents database as the outgoing information; and

an information selection means for selecting information to be segmented by said information segmentation means from said contents database in response to a request from a destination registered as an authorized user in said user database.

8. A system according to claim 7, further comprising:

a decryption key transmission means for transmitting a first key decryption for decrypting the encrypted first key to the destination registered as an authorized user in said user database.

9. A system according to claim 8, further comprising:

a second decryption key transmission means for transmitting a second key decryption key for decryption the encrypted second key to an authorized user when the authorized user who received the information selected by said information selection means as the outgoing information has paid a fee.

10. A system according to claim 3, further comprising:

a contents database for storing a plurality of kinds of contents data each of which contains blocks encrypted by said first encoder and blocks encrypted by said second encoder, and is to be included in the outgoing information; and

an information selection means for selecting contents data from said contents database and passing the selected data to said information sending means in response to a request from a destination.

11. An information sending method comprising:

segmenting information into a plurality of blocks;

encrypting more than one blocks of the plurality of blocks using a first key;

encrypting more than one block of blocks other than the blocks encrypted in the first encryption step using a second key; and

sending outgoing information including the blocks encrypted using the first key and the blocks encrypted using the second key to a first receiver, and sending outgoing information including blocks encrypted using the first key to a second receiver, wherein the first receiver being able to decrypt the blocks of the plurality of blocks encrypted by the first key and the blocks of the plurality of blocks encrypted by the second key using the first and second keys in order to understand meaning of the information, and a second receiver being able to decrypt the blocks of the plurality of blocks encrypted by the first key using the first key in order to check the blocks encrypted by the first key.

12. A method according to claim 11, further comprising:

appending, to the outgoing information, identification information indicating the blocks encrypted using the first key and the blocks encrypted using the second key contained in the outgoing information.

13. A method according to claim 12, further comprising:

appending, to the outgoing information, the encrypted first key, and the second key encrypted by an encryption key different from a key used for encrypting the first key.