Key mangement system and multicast delivery system using the same
AssigneeNEC Corporation
InventorsKazuya Suzuki, Masahiro Jibiki, Hideyuki Magoshi
Life of this patent
Estimating the term…
Abstract
In a multicast delivery system, A delivery server enciphers delivery data by using a current use cipher key to generate enciphered data and transmits a multicast packet containing the enciphered data and a current use key identifier indicative of a pair of the current use cipher key and a current use decipher key as current use keys. A key management server holds as a current use key data, a set of the current use decipher key and the current use key identifier, and transmits a set of the current use decipher key and the current use key identifier as a current use decipherment key data in response to a current use key data request.
Claims59
A multicast delivery system comprising:
- a delivery server which enciphers delivery data by using a current use cipher key to generate enciphered data and transmits a multicast packet containing said enciphered data and a current use key identifier indicative of a pair of said current use cipher key and a current use decipher key as current use keys;
- a key management server which is connected with said delivery server through a network, holds as a current use key data, a set of said current use decipher key and said current use key identifier, and transmits a set of said current use decipher key and said current use key identifier as a current use decipherment key data in response to a current use key data request;
- and
- a client terminal which is connected with said delivery server and said key management server through said network, receives said multicast packet from said deliver server, issues said current use key data request to said key management server to receive said current use decipherment key data from said key management server, holds said set of said current use decipher key and said current use key identifier, and deciphers said enciphered data contained in said multicast packet by using said current use decipher key when said current use key identifier contained in said multicast packet is coincident with said current use key identifier held in said client terminal.
A delivery server in a multicast delivery system, comprising:
- a key data management table which holds a current use cipher key and a current use key identifier for said current use cipher key;
- and
- an enciphering section which refers to said key data management table to acquires said current use cipher key, enciphers delivery data by using said current use cipher key to generate enciphered data and transmits a multicast packet containing said enciphered data and said current use key identifier indicative of a pair of said current use cipher key and a current use decipher key as current use keys.
A key management server in a multicast delivery system, comprising:
- a key data management table which holds a current use decipher key and a current use key identifier for said current use decipher key;
- and
- a key managing section which reads out said current use decipher key and said current use key identifier in response to a key data request to transmit to a request issuing client.
A client terminal in a multicast delivery system, comprising:
- a key data management table which holds a current use decipher key and a current use key identifier for said current use decipher key;
- and
- a key managing section which issues a current use key data request to acquire a current use key data of said current use decipher key and said current use key identifier, stores said current use key data in said key data management table, determines whether a transmission key identifier contained in a multicast packet with an enciphered data is present in said key data management table, deciphers said enciphered data by using said decipher key stored in said key data management, when it is determined that said transmission key identifier is present, issues a next use key data request to acquire a next use key data of a next use decipher key and a next use key identifier, when it is determined that said transmission key identifier is not present, and stores said next use key data in said key data management table.
A software product executable by a computer and storing a program executing functions of:
- referring to a key data management table to acquire a current use cipher key;
- enciphering delivery data by using said current use cipher key to generate enciphered data;
- and
- transmitting a multicast packet containing said enciphered data and said current use key identifier indicative of a pair of said current use cipher key and a current use decipher key as current use keys.
A software product executable by a computer and storing a program executing functions of:
- storing a current use decipher key and a current use key identifier for said current use decipher key in a key data management table;
- and
- reading out said current use decipher key and said current use key identifier in response to a key data request to transmit to a request issuing client.
A software product executable by a computer and storing a program executing the functions of:
- storing a current use decipher key and a current use key identifier for said current use decipher key in a key data management table;
- and
- issuing a current use key data request to acquire a current use key data of said current use decipher key and said current use key identifier, stores said current use key data in said key data management table;
- determining whether a transmission key identifier contained in a multicast packet with an enciphered data is present in said key data management table;
- deciphering said enciphered data by using said decipher key stored in said key data management, when it is determined that said transmission key identifier is present;
- issuing a next use key data request to acquire a next use key data of a next use decipher key and a next use key identifier, when it is determined that said transmission key identifier is not present;
- and
- storing said next use key data in said key data management table.
Dependencies are inferred from the claim text.