TRANSMITTING/RECEIVING SYSTEM AND METHOD, TRANSMITTING APPARATUS AND METHOD, RECEIVING APPARATUS AND METHOD, AND PROGRAM USED THEREWITH

• US 20070033399A1
• Filed: 07/31/2006
• Published: 02/08/2007
• Est. Priority Date: 08/02/2005
• Status: Active Grant

• Current Assignee: Sony Corporation (Sony Group Corp.)
• Original Assignee: Sony Corporation (Sony Group Corp.)
• Inventors: TAKEDA, Takayuki
• Granted Patent: US 8,108,674 B2
• Time in Patent Office: Days
• US Class Current: 713/168
• CPC Class Codes: H04L 2209/20 Manipulating the length of blocks of bits, e.g. padding or block truncation
• CPC Class Codes: H04L 9/065 Encryption by serially and continuously modifying data stream elements, e.g. stream cipher systems, RC4, SEAL or A5/3
• CPC Class Codes: H04L 9/16 the keys or algorithms being changed during operation

Abstract

A transmitting/receiving system includes a transmitting apparatus that transmits, to another apparatus, first encrypted data obtained by encrypting stream data including consecutive unit data items in accordance with a first encryption technique prescribing that, when the stream data is encrypted for each item, keys used for encrypting the items are updated, and a receiving apparatus that receives and decrypts the first data from the transmitting apparatus in accordance with a first decryption technique. The transmitting apparatus includes an encryptor that outputs second encrypted data obtained by generating data including a predetermined number of keys, and encrypting the data in accordance with a second encryption technique, a transmitter that transmits the second data from the encryptor to the receiving apparatus. The receiving apparatus includes a key receiver that receives the second data from the transmitter, and a key decryptor that decrypts the second data in accordance with a second decryption technique.

Claims

1. A transmitting/receiving system comprising:

a transmitting apparatus configured to transmit first encrypted data obtained by encrypting stream data including a plurality of consecutive unit data items in accordance with a first encryption technique prescribing that, when the stream data is sequentially encrypted for each unit data item, a plurality of keys used for encrypting the unit data items are updated on the basis of predetermined rules; and

a receiving apparatus configured to receive and decrypt the first encrypted data transmitted from the transmitting apparatus in accordance with a first decryption technique corresponding to the first encryption technique by using a plurality of keys used for generating the first encrypted data,

wherein

the transmitting apparatus includes

a key encryptor configured to output second encrypted data obtained by generating data including keys whose number is represented by an integer value equal to one or greater among the plurality of keys used for generating the first encrypted data, and encrypting the generated data in accordance with a second encryption technique, and

a key transmitter configured to transmit the second encrypted data output from the key encryptor to the receiving apparatus, and

the receiving apparatus includes

a key receiver configured to receive the second encrypted data transmitted from the key transmitter of the transmitting apparatus, and

a key decryptor configured to decrypt the second encrypted data received by the key receiver in accordance with a second decryption technique corresponding to the second encryption technique.

2. A transmitting/receiving method for a transmitting/receiving system including a transmitting apparatus configured to transmit, to a different apparatus, first encrypted data obtained by encrypting stream data including a plurality of consecutive unit data items in accordance with a first encryption technique prescribing that, when the stream data is sequentially encrypted for each unit data item, a plurality of keys used for encrypting the unit data items are updated on the basis of predetermined rules, and a receiving apparatus, as the different apparatus, configured to receive and decrypt the first encrypted data transmitted from the transmitting apparatus in accordance with a first decryption technique corresponding to the first encryption technique by using a plurality of keys used for generating the first encrypted data, the transmitting/receiving method comprising the steps of:

by the transmitting apparatus,

performing generation of data including keys whose number is represented by an integer value equal to one or greater among the plurality of keys used for generating the first encrypted data, and encryption of the generated data in accordance with a second encryption technique to generate second encrypted data; and

transmitting the second encrypted data to the receiving apparatus; and

by the receiving apparatus,

receiving the second encrypted data transmitted from the transmitting apparatus; and

decrypting the received second encrypted data in accordance with a second decryption technique corresponding to the second encryption technique.

3. A transmitting apparatus for transmitting, to a different apparatus, first encrypted data obtained by encrypting stream data including a plurality of consecutive unit data items in accordance with a first encryption technique prescribing that, when the stream data is sequentially encrypted for each unit data item, a plurality of keys used for encrypting the unit data items are updated on the basis of predetermined rules, the transmitting apparatus comprising:

a key encryptor configured to output second encrypted data obtained by generating data including i keys, where i represents an integer value equal to one or greater, among the plurality of keys used for generating the first encrypted data, and encrypting the generated data in accordance with a second encryption technique; and

a key transmitter configured to transmit the second encrypted data output from the key encryptor to the receiving apparatus.

4. The transmitting apparatus according to claim 3, wherein:

the second encryption technique uses the RSA encryption using 2048-bit data; and

the key encryptor generates data having a total of 2048 bits as data to be encrypted in accordance with the RSA encryption by generating i N-bit information-data items respectively including at least the i keys, where N represents an integer value equal to 2048 or less, and i represents an integer value satisfying the expression i×

N≦

2048, arranging the i N-bit information-data items in predetermined order, and, following the i N-bit information-data items, arranging padding data having (2048-i×

N) bits.

5. The transmitting apparatus according to claim 4, further comprising:

an Advanced-Encryption-Standard-key generator configured to generate Advanced-Encryption-Standard keys as the plurality of keys in accordance with the predetermined rules concerning key updating;

an Advanced-Encryption-Standard-input generator configured to generate an Advanced-Encryption-Standard input including link-encryption-attribute data; and

a stream encryptor configured to output the first encrypted data generated such that the stream data is encrypted by using the Advanced-Encryption-Standard keys generated by the Advanced-Encryption-Standard-key generator and the Advanced-Encryption-Standard input generated by the Advanced-Encryption-Standard-input generator, wherein

the first encryption technique uses the Advanced Encryption Standard, and

the key encryptor generates, as one information-data item, data including one Advanced-Encryption-Standard key generated by the Advanced-Encryption-Standard-key generator and the link-encryption-attribute data included in the Advanced-Encryption-Standard input generated by the Advanced-Encryption-Standard-input generator.

6. The transmitting apparatus according to claim 5, wherein:

each information-data item is formed as a 304-bit link-encryption-key payload; and

the key encryptor generates, as data to be encrypted in accordance with the RSA encryption, data having a total of 2048 bits by generating and arranging six link-encryption-key payloads in predetermined order, where six is equal to i, and, following the six link-encryption-key payloads, arranging 224-bit padding data.

7. The transmitting apparatus according to claim 5, wherein the key transmitter transmits the second encrypted data to the different apparatus by transmitting data obtained by superimposing the second encrypted data output from the key encryptor on the first encrypted data output from the stream encryptor.

8. A transmitting method for a transmitting apparatus for transmitting, to a different apparatus, first encrypted data obtained by encrypting stream data including a plurality of consecutive unit data items in accordance with a first encryption technique prescribing that, when the stream data is sequentially encrypted for each unit data item, a plurality of keys used for encrypting the unit data items are updated on the basis of predetermined rules, the transmitting method comprising the steps of:

generating data including keys whose number is represented by an integer value equal to one or greater among the plurality of keys used for generating the first encrypted data, and encrypting the generated data in accordance with a second encryption technique to generate second encrypted data; and

transmitting the generated second encrypted data to the different apparatus.

9. A program to be executed by a computer for controlling processing for transmitting, to a different apparatus, first encrypted data obtained by encrypting stream data including a plurality of consecutive unit data items in accordance with a first encryption technique prescribing that, when the stream data is sequentially encrypted for each unit data item, a plurality of keys used for encrypting the unit data items are updated on the basis of predetermined rules,

the program comprising the step of outputting second encrypted data obtained by generating data including keys whose number is represented by an integer value equal to one or greater among the plurality of keys used for generating the first encrypted data, and encrypting the generated data in accordance with a second encryption technique.

10. A receiving apparatus for receiving first encrypted data when the first encrypted data is transmitted from a transmitting apparatus after being obtained by encrypting stream data including a plurality of consecutive unit data items in accordance with a first encryption technique prescribing that, when the stream data is sequentially encrypted for each unit data item, a plurality of keys used for encrypting the unit data items are updated on the basis of predetermined rules, and decrypting the first encrypted data in accordance with a first decryption technique corresponding to the first encryption technique by using the plurality of keys used for generating the first encrypted data, the receiving apparatus comprising:

a key receiver configured to receive second encrypted data when the second encrypted data is transmitted from the transmitting apparatus after being obtained by generating data including i keys, where i represents an integer value equal to one or greater, among the plurality of keys used for generating the first encrypted data, and encrypting the generated data in accordance with a second encryption technique; and

a key decryptor configured to decrypt the second encrypted data received by the key receiver in accordance with a second decryption technique corresponding to the second encryption technique.

11. The receiving apparatus according to claim 10, wherein:

the second encryption technique uses the RSA encryption using 2048-bit data;

the transmitting apparatus generates, as data to be encrypted in accordance with the RSA encryption, data having a total of 2048 bits by generating i N-bit information-data items respectively including at least the i keys, where N represents an integer value equal to 2048 or less, and i represents an integer value satisfying the expression i×

N≦

2048, arranging the i N-bit information-data items in predetermined order, and, following the i N-bit information-data items, arranging padding data having (2048-i×

N) bits; and

the key decryptor restores the i information-data items by executing decryption in accordance with the second decryption technique, and extracts the keys respectively included in the i information-data items.

12. The receiving apparatus according to claim 11, wherein:

the first encryption technique uses the Advanced Encryption Standard;

the transmitting apparatus performs

generating Advanced-Encryption-Standard keys as the plurality of keys in accordance with the predetermined rules concerning key updating,

generating an Advanced-Encryption-Standard input including link-encryption-attribute data, outputting the first encrypted data generated such that the stream data is encrypted by using the generated Advanced-Encryption-Standard keys and the generated Advanced-Encryption-Standard input, and

generating, as one information-data item, data including one Advanced-Encryption-Standard key and the link-encryption-attribute data included in one Advanced-Encryption-Standard input;

the key decryptor restores the i information-data items by executing decryption in accordance with the second decryption technique, and extracts the Advanced-Encryption-Standard key and link-encryption-attribute data included in each of the i information-data items; and

the receiving apparatus further includes

an Advanced-Encryption-Standard-input generator configured to generate an Advanced-Encryption-Standard input corresponding to the Advanced-Encryption-Standard key extracted from a predetermined information-data item by the key decryptor by using the link-encryption-attribute data extracted from the predetermined information-data item by the key decryptor; and

a stream decryptor configured to decrypt a portion encrypted by using the Advanced-Encryption-Standard key and included in the first encrypted data by using the Advanced-Encryption-Standard key extracted from the predetermined information-data item by the key decryptor and the Advanced-Encryption-Standard input generated correspondingly to the Advanced-Encryption-Standard key by the Advanced-Encryption-Standard input generator.

13. The receiving apparatus according to claim 12, wherein:

each information-data item is formed as a 304-bit link-encryption-key payload; and

the transmitting apparatus generates, as data to be encrypted in accordance with the RSA encryption, data having a total of 2048 bits by generating and arranging six link-encryption-key payloads, where six is equal to i, in predetermined order, and, following the six link-encryption-key payloads, arranging 224-bit padding data.

14. The receiving apparatus according to claim 12, wherein, when data obtained by superimposing the second encrypted data on the first encrypted data is transmitted to the receiving apparatus, after the key receiver receives and separates the data into the first encrypted data and the second encrypted data, the key receiver provides the first encrypted data to the stream decryptor and provides the second encrypted data to the key decryptor.

15. A receiving method for a receiving apparatus for receiving first encrypted data when the first encrypted data is transmitted from a transmitting apparatus after being obtained by encrypting stream data including a plurality of consecutive unit data items in accordance with a first encryption technique prescribing that, when the stream data is sequentially encrypted for each unit data item, a plurality of keys used for encrypting the unit data items are updated on the basis of predetermined rules, and for decrypting the first encrypted data in accordance with a first decryption technique corresponding to the first encryption technique by using the plurality of keys used for generating the first encrypted data, the receiving method comprising the steps of:

receiving second encrypted data when the second encrypted data is transmitted from the transmitting apparatus after being obtained by generating data including keys whose number is represented by an integer value equal to one or greater among the plurality of keys used for generating the first encrypted data, and encrypting the generated data in accordance with a second encryption technique; and

decrypting the received second encrypted data in accordance with a second decryption technique corresponding to the second encryption technique.

16. A program to be executed by a computer for controlling:

processing for receiving first encrypted data when the first encrypted data is transmitted from a predetermined apparatus after being obtained by encrypting stream data including a plurality of consecutive unit data items in accordance with a first encryption technique prescribing that, when the stream data is sequentially encrypted for each unit data item, a plurality of keys used for encrypting the unit data items are updated on the basis of predetermined rules, and decrypting the first encrypted data in accordance with a first decryption technique corresponding to the first encryption technique by using the plurality of keys used for generating the first encrypted data; and

processing for receiving second encrypted data when the second encrypted data is transmitted from the predetermined apparatus after being obtained by generating data including keys whose number is represented by an integer value equal to one or greater among the plurality of keys used for generating the first encrypted data, and encrypting the generated data in accordance with a second encryption technique,

the program comprising the step of decrypting the received second encrypted data in accordance with a second decryption technique corresponding to the second encryption technique.