Communication apparatus, communication system, transmission method, and computer program product
First Claim
1. A communication apparatus that transmits a plurality of pieces as a part of a content, comprising:
- a first storage unit that stores a plurality of encrypted pieces obtained by encrypting each of the pieces by an encryption key, and that stores a plurality of encrypted pieces obtained by encrypting at least one of first pieces among the pieces by a plurality of different encryption keys;
a second storage unit that stores number of transmission times of each of the encrypted pieces stored in the first storage unit;
a selecting unit that selects as priority pieces the encrypted pieces corresponding to at least one of the first pieces, based on number of untransmitted encrypted pieces of which number of transmission times is zero among the encrypted pieces of which the first piece is encrypted;
a storage control unit that controls the second storage unit so that the second storage unit additionally stores priority piece information specifying a selected priority piece, in the second storage unit;
a receiving unit that receives a piece request requesting an encrypted piece, from other communication apparatus;
a first determining unit that determines as transmission candidates the encrypted pieces specified as the priority pieces by the priority piece information, when the piece request is received;
a second determining unit that determines at least one of the untransmitted encrypted pieces as an encrypted piece to be transmitted, among the encrypted pieces determined as transmission candidates;
a transmitting unit that transmits the encrypted piece determined to be transmitted, to the other communication apparatus;
a first updating unit that updates number of transmission times of each of the encrypted pieces stored in the second storage unit, in accordance with the encrypted piece transmitted by the transmitting unit;
a second updating unit that updates the priority piece information stored in the second storage unit, in the second storage unit, so that the priority piece becomes in an initial state not specified by the priority piece information, when the untransmitted encrypted piece is not present any more among the encrypted pieces specified as priority pieces by the priority piece information; and
a processor configured to execute at least the selecting unit.
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Accused Products
Abstract
A communication apparatus stores encrypted pieces having plural pieces as a part of a content encrypted, and number of transmission times. At least one first piece is encrypted by plural different encryption keys. The communication apparatus selects as priority pieces plural encrypted pieces corresponding to at least one first piece among the first pieces, based on number of untransmitted encrypted pieces of which number of transmission times is zero among plural encrypted pieces of which first piece is encrypted, and stores priority piece information specifying the priority piece. When a piece request is received from other communication apparatus, the communication apparatus determines an encrypted piece to be transmitted, based on priority piece information, and transmits the encrypted piece to the other communication apparatus.
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Citations
25 Claims
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1. A communication apparatus that transmits a plurality of pieces as a part of a content, comprising:
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a first storage unit that stores a plurality of encrypted pieces obtained by encrypting each of the pieces by an encryption key, and that stores a plurality of encrypted pieces obtained by encrypting at least one of first pieces among the pieces by a plurality of different encryption keys; a second storage unit that stores number of transmission times of each of the encrypted pieces stored in the first storage unit; a selecting unit that selects as priority pieces the encrypted pieces corresponding to at least one of the first pieces, based on number of untransmitted encrypted pieces of which number of transmission times is zero among the encrypted pieces of which the first piece is encrypted; a storage control unit that controls the second storage unit so that the second storage unit additionally stores priority piece information specifying a selected priority piece, in the second storage unit; a receiving unit that receives a piece request requesting an encrypted piece, from other communication apparatus; a first determining unit that determines as transmission candidates the encrypted pieces specified as the priority pieces by the priority piece information, when the piece request is received; a second determining unit that determines at least one of the untransmitted encrypted pieces as an encrypted piece to be transmitted, among the encrypted pieces determined as transmission candidates; a transmitting unit that transmits the encrypted piece determined to be transmitted, to the other communication apparatus; a first updating unit that updates number of transmission times of each of the encrypted pieces stored in the second storage unit, in accordance with the encrypted piece transmitted by the transmitting unit; a second updating unit that updates the priority piece information stored in the second storage unit, in the second storage unit, so that the priority piece becomes in an initial state not specified by the priority piece information, when the untransmitted encrypted piece is not present any more among the encrypted pieces specified as priority pieces by the priority piece information; and a processor configured to execute at least the selecting unit. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21)
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22. A communication system comprising:
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a first communication apparatus performing transmission and reception of a plurality of pieces as a part of a content; and a second communication apparatus performing transmission and reception of a plurality of pieces as a part of a content, the a first communication apparatus and the second communication apparatus being connected via a network, wherein each of the first communication apparatus and the second communication apparatus includes a first storage unit that stores a plurality of encrypted pieces obtained by encrypting each of the pieces by an encryption key, and that stores a plurality of encrypted pieces obtained by encrypting at least one of first pieces among the pieces by a plurality of different encryption keys, a second storage unit that stores number of transmission times of each of the encrypted pieces stored in the first storage unit, a selecting unit that selects as priority pieces the plurality of encrypted pieces corresponding to at least one of the first pieces, based on number of untransmitted encrypted pieces of which number of transmission times is zero among the encrypted pieces of which the first piece is encrypted, a storage control unit that controls the second storage unit so that the second storage unit additionally stores priority piece information specifying a selected priority piece, a receiving unit that receives a piece request requesting an encrypted piece, from other communication apparatus, a first determining unit that determines as transmission candidates the encrypted pieces specified as the priority pieces by the priority piece information, when the piece request is received, a second determining unit that determines at least one of the untransmitted encrypted pieces as an encrypted piece to be transmitted, among the encrypted pieces determined as transmission candidates, a transmitting unit that transmits the encrypted piece determined to be transmitted, to the other communication apparatus, a first updating unit that updates number of transmission times of each of the encrypted pieces stored in the second storage unit, following the encrypted piece transmitted by the transmitting unit, a second updating unit that updates the priority piece information in the second storage unit, so that the priority piece becomes in an initial state not specified by the priority piece information, when the untransmitted encrypted piece is not present any more among the encrypted pieces specified as priority pieces by the priority piece information, a piece receiving unit that receives the encrypted piece from other communication apparatus, a piece-storage control unit that controls the first storage unit so that the first storage unit additionally stores the received encrypted piece, and a processor configured to execute at least the selecting unit, and wherein the transmitting unit included in the first communication apparatus transmits the encrypted piece determined to be transmitted, to the second communication apparatus, and the piece receiving unit included in the second communication apparatus receives the encrypted piece transmitted from the transmitting unit included in the first communication apparatus. - View Dependent Claims (23)
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24. A transmitting method implemented in a communication apparatus that transmits a plurality of pieces as a part of a content, and includes a first storage unit that is a storage unit storing a plurality of encrypted pieces obtained by encrypting each of the pieces by an encryption key, and that stores a plurality of encrypted pieces obtained by encrypting at least one of first pieces among the pieces by a plurality of different encryption keys, and a second storage unit that stores number of transmission times of each of the encrypted pieces stored in the first storage unit, the method comprising:
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selecting as priority pieces the encrypted pieces corresponding to at least one of the first pieces, based on number of untransmitted encrypted pieces of which number of transmission times is zero among the encrypted pieces of which the first piece is encrypted; controlling the second storage unit so that the second storage unit additionally stores priority piece information specifying a selected priority piece; receiving a piece request requesting an encrypted piece from other communication apparatus; determining as transmission candidates the encrypted pieces specified as the priority pieces by the priority piece information, when the piece request is received; determining at least one of the untransmitted encrypted pieces as an encrypted piece to be transmitted, among the encrypted pieces determined as transmission candidates; transmitting the encrypted piece determined to be transmitted, to the other communication apparatus; updating number of transmission times of each of the encrypted pieces stored in the second storage unit, in accordance with the transmitted encrypted piece; and updating the priority piece information stored in the second storage unit, in the second storage unit, so that the priority piece becomes in an initial state not specified by the priority piece information, when the untransmitted encrypted piece is not present any more among the encrypted pieces specified as priority pieces by the priority piece information.
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25. A computer program product having including a non-transitory computer readable medium including programmed instructions, when executed by a computer provided in a communication apparatus that transmits a plurality of pieces as a part of a content, and includes a first storage unit that is a storage unit storing a plurality of encrypted pieces obtained by encrypting each of the pieces by an encryption key, and that stores a plurality of encrypted pieces obtained by encrypting at least one of first pieces among the pieces by a plurality of different encryption keys, and a second storage unit that stores number of transmission times of each of the encrypted pieces stored in the first storage unit, wherein the instructions, cause the computer to perform:
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selecting as priority pieces the encrypted pieces corresponding to at least one of the first pieces, based on number of untransmitted encrypted pieces of which number of transmission times is zero among the encrypted pieces of which the first piece is encrypted; controlling the second storage unit so that the second storage unit additionally stores priority piece information specifying a selected priority piece in the second storage unit; receiving a piece request requesting an encrypted piece from other communication apparatus; determining as transmission candidates the encrypted pieces specified as the priority pieces by the priority piece information, when the piece request is received; determining at least one of the untransmitted encrypted pieces as an encrypted piece to be transmitted, among the encrypted pieces determined as transmission candidates; transmitting the encrypted piece determined to be transmitted, to the other communication apparatus; updating number of transmission times of each of the encrypted pieces stored in the second storage unit, in accordance with the transmitted encrypted piece; and updating the priority piece information stored in the second storage unit, in the second storage unit, so that the priority piece becomes in an initial state not specified by the priority piece information, when the untransmitted encrypted piece is not present any more among the encrypted pieces specified as priority pieces by the priority piece information.
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Specification