EP0166541B1
Expired / Lapsed
EP
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Communications network using an enciphering and deciphering device
Assignee: Toshiba Corp
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Filing: 1985-05-30
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Granted: 1991-03-20
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Expires: 2005-05-30
Abstract
No abstract record available.
Inventors
- 👤 Hiroyuki C/O Patent Division Mizatani
- 👤 Takashi C/O Patent Division Kamitake
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-27 04:15
CPC Classifications
H; H03; H03M; H03M7/00; G; G07; G07F; G07F7/00; G07F7/08; G07F7/10; G07F7/1008; G06; G06Q; G06Q20/00; G06Q20/08; G06Q20/085; G06Q20/30; G06Q20/34; G06Q20/341; G06Q20/36; G06Q20/367; G06Q20/3674; G06Q20/38; G06Q20/40; G06Q20/409; G06Q20/4097; G06Q20/40975; G07F7/1016; H04; H04L; H04L9/00; H04L9/32; H04L9/3234; H04L9/3247; H04L2209/00; H04L2209/56
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
328 words
A communications network system in which a plurality of transmitting terminals and one receiving terminal are connected by communication lines, characterized in that each transmitting terminal (11...11n) comprises an enciphering device (14...14 0 ) for enciphering a communication message (M) to be transmitted by a sender to said receiving terminal, and transmitting means (23) for transmitting an output signal of said enciphering device to said receiving terminal via a communication line; said receiving terminal (12) comprises receiving means (25) for receiving the enciphered message (M') from said transmitting terminal and a deciphering device (15) for deciphering the received enciphered message; said enciphering device comprises key memory means (32, 33, 34, 53) for storing key data (R, I, S) which can specify the sender and the communication sent by the sender to said receiving terminal, and enciphering means (31, 35, 36, 51, 52, 54) for enciphering, according to a prescribed enciphering algorithm using the key data stored in said key memory means, the message (M) input from the outside to be transmitted to said receiving terminal, and for outputting the enciphered message (M') and the key data (I) which can specify the sender, said key memory . means and enciphering means being sealed inside said enciphering device such that the stored key data and enciphering algorithm cannot be accessed from the outside; and said deciphering device comprises key memory means (42, 43, 44, 53) for storing key data which can specify the sender and the communication sent by the sender to said receiving terminal, and deciphering means (41, 45, 46, 51, 52, 54) for deciphering, according to a prescribed deciphering algorithm different from the enciphering algorithm using the key data stored in said key memory means, the message (M') transmitted from said transmitting terminal, and for outputting the deciphered message (M), said key memory means and deciphering means being sealed inside said deciphering device such that the stored key data and enciphering algorithm cannot be accessed from the outside.
Claim 2
Dependent Claim
328 words
A communications network system in which a plurality of transmitting terminals and one receiving terminal are connected by communication lines, characterized in that each transmitting terminal (11...11n) comprises an enciphering device (14...14 0 ) for enciphering a communication message (M) to be transmitted by a sender to said receiving terminal, and transmitting means (23) for transmitting an output signal of said enciphering device to said receiving terminal via a communication line; said receiving terminal (12) comprises receiving means (25) for receiving the enciphered message (M') from said transmitting terminal and a deciphering device (15) for deciphering the received enciphered message; said enciphering device comprises key memory means (32, 33, 34, 53) for storing key data (R, I, S) which can specify the sender and the communication sent by the sender to said receiving terminal, and enciphering means (31, 35, 36, 51, 52, 54) for enciphering, according to a prescribed enciphering algorithm using the key data stored in said key memory means, the message (M) input from the outside to be transmitted to said receiving terminal, and for outputting the enciphered message (M') and the key data (I) which can specify the sender, said key memory . means and enciphering means being sealed inside said enciphering device such that the stored key data and enciphering algorithm cannot be accessed from the outside; and said deciphering device comprises key memory means (42, 43, 44, 53) for storing key data which can specify the sender and the communication sent by the sender to said receiving terminal, and deciphering means (41, 45, 46, 51, 52, 54) for deciphering, according to a prescribed deciphering algorithm different from the enciphering algorithm using the key data stored in said key memory means, the message (M') transmitted from said transmitting terminal, and for outputting the deciphered message (M), said key memory means and deciphering means being sealed inside said deciphering device such that the stored key data and enciphering algorithm cannot be accessed from the outside.
Claim 3
Dependent Claim
25 words
The network system according to claim 1, characterized in that said enciphering device and deciphering device are each a portable card containing a semiconductor circuit.
Claim 4
Dependent Claim
179 words
The network system according to claim 1, characterized in that said receiving terminal is arranged to send a key word (R), which can specify the communication, to a transmitting terminal in response to a request from the transmitting terminal, the key word being stored in said key memory means of said deciphering device; the key data stored in said key memory means of said enciphering device and used to encipher a message as well as to specify the sender and the communication includes a key word (I) which is peculiar to the sender, a common word (S) shared by the network, and a key word (R) which specifies the communication sent from said receiving terminal; and the key data stored in said key memory means of said deciphering device and used to decipher a message as well as to specify the sender and the message includes the key word (I) which is peculiar to the sender, the common key word (S) shared by the network, and the key word (R) which specifies the communication generated by the receiving terminal.
Claim 5
Dependent Claim
37 words
The network system according to claim 3, characterized in that the key word (R) which can specify the communication generated by said receiving terminal is a random number generated in compliance with a request from the sender.
Claim 6
Dependent Claim
24 words
The network system according to claim 1, characterized in that the DES (Data Encription Standard) system is used as the enciphering and deciphering algorithms.
Claim 7
Dependent Claim
66 words
The network system according to claim 3, characterized in that the key word (I) peculiar to the sender and the key word (S) common to the network are stored in said key memory means in an unrewritable form in said enciphering device, and the key word (S) common to the network is stored in said key memory means in an unrewritable form in said deciphering device.
Claim 8
Dependent Claim
28 words
The network system according to claim 3, characterized in that the key word (S) common to the network cannot be read out from said enciphering and deciphering devices.
Claim 9
Dependent Claim
35 words
A two-way network system using said network system defined in claim 1, characterized in that said receiving terminal can be used as a transmitting terminal, and said transmitting terminals can be used as receiving terminals.
Claim 10
Dependent Claim
43 words
The two-way network system according to claim 7, characterized in that a message sent from one transmitting terminal to said receiving terminals is enciphered using the deciphering algorithm, and the enciphered message is deciphered at said receiving terminals according to the enciphering algorithm.
References Cited (Backward Citations)
No citation records indexed.
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