Security method, security software and security system for electronic communications

• US 6,742,116 B1
• Filed: 08/30/1999
• Issued: 05/25/2004
• Est. Priority Date: 09/30/1998
• Status: Expired due to Fees

• Current Assignee: Fujitsu Limited
• Original Assignee: Fujitsu Limited
• Inventors: Matsui, Kazuki, Matsumoto, Tatsuro
• Primary Examiner(s): Barron, Gilberto
• Assistant Examiner(s): NOBAHAR, ABDULHAKIM
• Application Number:
  US09/385,961
• Time in Patent Office: 1,730 Days
• Field of Search: 713/171, 713/163, 713/202, 380/277, 709/204, 709/205
• US Class Current: 713/171
• CPC Class Codes: H04L 12/1813 for computer conferences, e.g. chat rooms instant messaging H04L51/04; protocols for multimedia communication H04L65/1101; arrangements for multi-party communication H04L65/403; telephonic conference arrangements H04M3/56; television conference systems H04N7/15
• CPC Class Codes: H04L 2209/60 Digital content management, e.g. content distribution
• CPC Class Codes: H04L 63/0435 wherein the sending and receiving network entities apply symmetric encryption, i.e. same key used for encryption and decryption cryptographic mechanisms or cryptographic arrangements for symmetric key encryption H04L9/06
• CPC Class Codes: H04L 63/065 for group communications cryptographic mechanisms or cryptographic arrangements for key management involving conference or group key H04L9/0833
• CPC Class Codes: H04L 9/0833 involving conference or group key network architectures or network communication protocols for key management in group communication in a packet data network H04L63/065
• CPC Class Codes: H04L 9/0894 Escrow, recovery or storing of secret information, e.g. secret key escrow or cryptographic key storage

Abstract

A security program is installed on a plurality of user terminals that communicate with one another via an electronic conference room. A command interpreter (3) of the security program specifies a chat channel (CHi), a coordinated event (Ti), and an private key (Si), and then directs a common key generator (5) to generate a common key (CSi). The common key generator (5) generates a common key based on at least one of (CHi), (Ti), and (Si), and then stores the common key in a common key memorizer (6). The common key memorizer 6 stores the common key with reference to an index. An encrypter/decrypter (7) encrypts a conversation datum inputted with a newest common key, and transmits to other user terminals the encrypted conversation datum along with an index corresponding to the coordinated event used to generate the common key used to encrypt the conversation datum. The encrypter/decrypter (7) receives conversation datum generated by other user terminals, and decrypts the conversation datum using the common key. The common key to decrypt the conversation datum is retrieved from the common key memorizer (6) using the index received with the conversation datum.

Claims

1. A method of ensuring privacy and security in a communication system as an electronic conference room where a plurality of user terminals communicate with one other over a network, said method comprising:

detecting predetermined changes in the electronic conference room;

designating the detected changes as coordinated events;

generating a series common key at each of the user terminals, each of the common keys being generated based upon the coordinated events;

storing at each of the user terminals the generated common keys, each common key having a unique index identifying that common key;

encrypting at sending user terminals a communication using one of the stored common keys;

transmitting over the network from the sending user terminal the encrypted communication along with one of the indexes corresponding to the one specific common key used to encrypt the communication; and

receiving at receiving user terminals the encrypted communication along with an index that identifies the common key used for encrypting the encrypted communication; and

decrypting in the receiving user terminals the encrypted communication using the common key identified according to the index.

2. The method as set forth in claim 1, wherein each coordinated event is identifiable by all of the user terminals and the unique index identifying the common key is based upon the coordinated event based on which the common key is generated.

3. The method as set forth in claim 2, wherein the coordinated event is based upon predetermined time intervals.

4. The method as set forth in claim 2, wherein the coordinated event is based upon actions taken in the electronic conference room.

5. A communication system ensuring secure and private communications between a plurality of user terminals transmitting communications to each other over a communication network via a communication server, the system comprising:

a storage in each user terminal storing security information;

a computer processor in each user terminal and programmed to control the user terminal according to a process comprising;

commanding identification of an identifier corresponding to an electronic conference room administered by the communication server through which the plurality of user terminals communicate with one another,

generating a plurality of common keys based upon the identifier, each generated common key having a unique index identifying the common key,

detecting predetermined changes in the electronic conference room,

designating the detected changes as coordinated events,

generating a plurality of new common keys based upon the coordinate events, each new common key having as the unique index a coordinate event that triggered generation of the new common key,

storing the generated common keys in the storage such that each common key is identifiable by each unique index,

encrypting communications to be sent from one user terminal to other user terminals via the communication server, the encrypting using a newest of the common keys stored in the storage,

transmitting, via the communication server, the encrypted communications to the other user terminals along with one of the indexes corresponding to the encrypting communication key,

receiving transmitted encrypted communications from the other user terminals via the communication server, and

decrypting the encrypted transmitted communications from other user terminals by using a received unique index to identify an encrypting common key from the storage.

6. The communication system as set forth in claim 5, wherein said commanding further comprises designating each coordinated event according to a predetermined passage of time.

7. The communication system as set forth in claim 6, wherein:

the storage stores a plurality of private keys, the plurality of private keys indexed according to each coordinated event of the predetermined passage of time, and

the commanding identifies one of the private keys based on the indexing according to the coordinated event of the predetermined passage of time and generates the plurality of the new common keys based upon the coordinated events and the private keys identified based upon the coordinated events.

8. The communication system as set forth in claim 7, further comprising a private key generator generating the plurality of the private keys and the corresponding indices.

9. The communication system as set forth in claim 5, wherein said encrypting is selectively controlled in an encryption on mode where communications are encrypted prior to the transmitting, and an encryption off mode where communications are not encrypted prior to the transmitting.

10. The communication system as set forth in claim 9, wherein said transmitting transmits communications along with a flag designating one of said encryption on mode and said encryption off mode.

11. The system of claim 10, wherein the programmed computer processor further display a sign that visually indicates whether a received communication is encrypted.

12. The system of claim 5, wherein:

access to the electronic conference room of the communication server is restricted by usage of a password, and the communication server is configured to selectively create a new password and transmit the new password to each of the user terminals; and

said commanding detects the new password and designates creation of the new password as a coordinated event, and in response to the detection of the new password, generates another new common key having a unique index corresponding to the coordinated event.

13. The system of claim 5, wherein a date change a coordinated event.

14. The system of claim 5, wherein a change in a number of user terminals engaged in communication with the electronic conference room is a coordinated event.

15. The system of claim 5, wherein each of the user terminals is configured to process a request from a user at one of the user terminals for generation of a new common key, and the commanding designates the request as a coordinated event.

16. A communication system ensuring secure and private communications between a plurality of user terminals transmitting communications to each other over a communication network via a communication server, the system comprising:

storing means in each user terminal for, storing security information;

commanding means in each user terminal for controlling the user terminal according to a process comprising;

commanding identification of an identifier corresponding to an electronic conference room administered by the communication server through which the plurality of user terminals communicate with one another,

generating the plurality of common keys based on the identifier, each generated common key having a unique index identifying the common key,

storing the generated common keys in the storing means such that each common key is identifiable by the unique index,

defining a limit on a maximum number of common keys storable in said storing means, and

once the maximum number of the common keys has been stored in said storing means, deleting an oldest of the common keys to make room for a new common key;

encrypting means in each user terminal for encrypting communications to be sent from one user terminal to other user terminals via the communication server, the encrypting means using a newest of the common keys stored in the storing means,

transmitting means in each user terminal for transmitting, via the communication server, the encrypted communications to the other user terminals along with one of the indexes corresponding to the encrypting communication key;

receiving means in each user terminal for receiving transmitted encrypted communications from the other user terminals via the communication server; and

decryptng means in each user terminal for decrypting the encrypted transmitted communications from other user terminals using a received unique index to identify an encrypting common key from said storing means.

17. The system of claim 16, wherein a date change is a coordinating event that triggers the generating of one of said common keys and a corresponding unique index.

18. A computer-readable recording medium on which a security program is stored, the security program being adapted for use with a communication system which includes communication as an electronic conference room between a plurality of user terminals over a network, the security program being adapted to control a user terminal according to a process comprising:

storing at least one private key;

detecting predetermined changes in the electronic conference room;

designating the detected changes in the electronic conference room as coordinated events;

specifying an identifier corresponding to an electronic conference room on the network, a coordinated event and a private key;

generating separately in each user terminal at least one common key based on the specified electronic conference room identifier, the coordinated event, and the private key;

storing the generated common keys such that each common key is identifiable by an index that corresponds to the coordinated event based upon which the common key was generated;

processing a communication to be transmitted to the electronic conference room by encrypting content of the communication using a newest of the at least one stored generated common key;

sending the encrypted communication along with one of the indexes corresponding to the newest common key used to encrypt the contents of the communication;

receiving a communication message from the electronic conference room;

extracting an index from the received communication message;

identifying one of the stored generated common keys using the extracted index; and

decrypting the encrypted contents of the received communication message using the identified common key.

19. The computer-readable recording medium of claim 18, wherein the coordinated events are based upon passage of predetermined periods of time.

20. The computer-readable recording medium claim 18, wherein the coordinated events are based upon actions taken by at least one of the user terminals.

21. The computer-readable recording medium of claim 20, wherein the actions comprise at least one of a request for a new common key and a change in a number of user terminals engaged in a conversation in the electronic conference room.

22. A communication system comprising:

a plurality of user terminals that communicate with one another over a network; and

a server adapted to distribute communications between said plurality of user terminals;

each user terminal comprising;

commanding means for controlling the user terminal according to a process comprising;

commanding identification of an identifier corresponding to an electronic conference room administered by the communication server through which the plurality of user terminals communicate with one another,

generating a plurality of common keys based on the identifier, each generated common key having a unique index identifying each common key,

detecting predetermined changes in the electronic conference room,

designating the detected changes as coordinated events,

generating a plurality of new common keys based upon the coordinated events, each new common key having as the unique index a coordinated event that triggered generation of the new common key, and

storing the generated common key such that the common key is identifiable by each unique index;

encrypting means for encrypting communications to be sent from one user terminal to other user terminals via the communication server, the encrypting means using a newest of the common keys stored in the storing means;

transmitting means for transmitting, via the communication server, the encrypted communications to the other user terminals along with one of the indexes corresponding to the encrypting communication key;

receiving means for receiving transmitted encrypted communications from the other user terminals via the communication server; and

decrypting means for decrypting the encrypted transmitted communications from other user terminals using a received unique index to identify an encrypting common key from said storing means.

23. The communication system of claim 22, wherein said commanding means designates each coordinated event in accordance with a predetermined passage of time.

24. A machine-readable storage storing at least one program controlling a user terminal, which is in communication with other user terminals over a communication network via a communication server, according to a process comprising:

commanding identification of an identifier corresponding to an electronic conference room administered by the communication server through which the plurality of user terminals communicate with one another;

generating a plurality of common keys based upon the identifier, each generated common key having a unique index identifying the common key;

detecting predetermined changes In the electronic conference room;

designating the detected changes as coordinated events;

generating the plurality of new common keys based upon the coordinate events, each new common key having as the unique index a coordinate event that triggered generation of the new common key;

storing the generated common keys such that each common key is identifiable by each unique index;

encrypting communications to be sent from one user terminal to other user terminals via the communication server, the encrypting using a newest of the stored common keys;

transmitting, via the communication server, the encrypted communications to the other user terminals along with one of the indexes corresponding to the encrypting communication key;

receiving transmitted encrypted communications from the other user terminals via the communication server; and

decrypting the encrypted transmitted communications from other user terminals by using a received unique index to identify a stored encrypting common key.

25. A machine-readable storage storing at least one program controlling a user terminal, which is in communication with other user terminals over a communication network via a communication server, according to a process comprising:

commanding identification of an identifier corresponding to an electronic conference room administered by the communication server through which the plurality of user terminals communicate with one another;

generating the plurality of common keys based on the identifier, each generated common key having a unique index identifying the common key;

storing the generated common keys such that each common key is identifiable by the unique index;

defining a limit on a maximum number of common keys storable;

once the maximum number of the common keys has been stored, deleting an oldest of the common keys to make room for a new common key;

encrypting communications to be sent from one user terminal to other user terminals via the communication server, the encrypting using a newest of the stored common keys;

transmitting, via the communication server, the encrypted communications to the other user terminals along with one of the indexes corresponding to the encrypting communication key;

receiving transmitted encrypted communications from the other user terminals via the communication server; and

decrypting the encrypted transmitted communications from other user terminals using a received unique index to identify a stored encrypting common key.

26. A method of controlling a user terminal, which is in communication with other user terminals over a communication network via a communication server, comprising:

storing at least one private key;

detecting predetermined changes in the electronic conference room;

designating the detected changes in the electronic conference room as coordinated events;

specifying an identifier corresponding to an electronic conference room on the network, a coordinated event, and a private key;

generating separately in each user terminal at least one common key based on the specified electronic conference room identifier, the coordinated event and the private key;

storing the generated common keys such that each common key is identifiable by an index that corresponds to the coordinated event based upon which the common key is generated, one index per common key;

processing a communication to be transmitted to the electronic conference room by encrypting content of the communication using a newest of the at least one stored generated common key;

sending the encrypted communication along with one of the indexes corresponding to the newest common key used to encrypt the contents of the communication;

receiving a communication message from the electronic conference room;

extracting an index from the received communication message;

identifying one of the stored generated common keys using the extracted index; and

decrypting the encrypted contents of the received communication message using the identified common key.

27. A method of controlling a user terminal, which is in communication with other user terminals over a communication network via a communication server, comprising:

commanding identification of an identifier corresponding to an electronic conference room administered by the communication server through which the plurality of user terminals communicate with one another;

generating the plurality of common keys based on the identifier, each generated common key having a unique index identifying the common key;

storing the generated common keys such that each common key is identifiable by the unique index;

defining a limit on a maximum number of common keys storable;

once the maximum number of the common keys has been stored, deleting an oldest of the common keys to make room for a new common key;

encrypting communications to be sent from one user terminal to other user terminals via the communication server, the encrypting using a newest of the stored common keys;

transmitting, via the communication server, the encrypted communications to the other user terminals along with one of the indexes corresponding to the encrypting communication key;

receiving transmitted encrypted communications from the other user terminals via the communication server; and

decrypting the encrypted transmitted communications from other user terminals using a received unique index to identify a stored encrypting common key.

28. A data communication system, comprising:

a plurality of user terminals that communicate with one another over a network, each user terminal comprising;

a computer processor programmed to control the user terminal according to a process comprising;

commanding identification of an identifier corresponding to an electronic conference room via the network through which the plurality of user terminals communicate with one another,

generating a plurality of common keys based upon the identifier, each generated common key having a unique index identifying the common key,

detecting predetermined changes in the electronic conference room,

designating the detected changes as coordinated events,

generating the plurality of common keys based upon the coordinate events, each common key having a coordinate event that triggered generation of the common key as the unique index,

storing the generated common keys such that each common key is identifiable by each unique index,

encrypting communications to be sent from one user terminal to other user terminals via the network, the encrypting using a newest of the stored common keys,

transmitting, via the network, the encrypted communications to the other user terminals along with one of the indexes corresponding to the encrypting communication key,

receiving transmitted encrypted communications from the other user terminals via network, and

decrypting the encrypted transmitted communications from other user terminals by using a received unique index to identify a stored encrypting common key.