Method for connection of secure conference calls

• US 4,920,565 A
• Filed: 07/18/1988
• Issued: 04/24/1990
• Est. Priority Date: 07/18/1988
• Status: Expired due to Fees

• Current Assignee: Nortel Networks Limited (Nortel Networks Corporation)
• Original Assignee: Northern Telecom Limited (Nortel Networks Corporation)
• Inventors: Strawczynski, Leo, Steer, David G.
• Primary Examiner(s): CANGIALOSI, SALVATORE A
• Application Number:
  US07/220,190
• Time in Patent Office: 645 Days
• Field of Search: 380/6, 380/8, 380/9, 380/33, 380/34
• US Class Current: 380/257
• CPC Class Codes: H04K 1/00 Secret communication
• CPC Class Codes: H04M 2203/609 Secret communication
• CPC Class Codes: H04M 3/561 by multiplexing
• CPC Class Codes: H04M 3/568 audio processing specific to telephonic conferencing, e.g. spatial distribution, mixing of participants echo suppression in two-way loud-speaking telephone systems H04M9/02; sound field processing per se H04S7/30

Abstract

The present invention provides a method and apparatus of making secure conference calls in which the bridging unit does not need to know any encryption keys and can function independently of the encryption process used by the communicating parties. This means that there is no security requirement for the conference unit, there are fewer restrictions on where it can be placed, and it does not introduce any additional weaknesses in the security system.

Claims

1. A method of bridging teleconference calls at each telephone set used within a teleconference network, comprising the steps of:

receiving a first incoming signal from a first adjacent teleconference user via a first logical channel;

decoding said first incoming signal to provide a first incoming speech signal;

forwarding said first incoming speech signal to a first input of a signal processing circuit means;

receiving a second incoming signal from a second adjacent teleconference user via a second logical channel;

decoding said second incoming signal to provide a second incoming speech signal;

forwarding said second incoming speech signal to a second input of said signal processing circuit means;

detecting the presence of and decoding a user'"'"'s output speech signal from an output of user interface means;

forwarding said output speech signal if present to a third input of said signal processing circuit means;

summing said speech signals of said first and second inputs at said signal processing means and forwarding the summed signal to an input of code translation circuit means for conversion and forwarding to an input of said user interface means;

summing said speech signals of said second and third inputs at said signal processing means to provide a first outgoing speech signal;

coding said first outgoing speech signal to provide a first outgoing signal;

transmitting said first outgoing signal to said first adjacent user via said first logical channel;

summing said speech signals of said first and third inputs at said signal processing circuit means to provide a second outgoing speech signal;

coding said second outgoing speech signal to provide a second outgoing signal; and

transmitting said second outgoing signal to said second adjacent user via said second logical channel.

2. A method as defined in claim 1 further comprising the step of instructing said communications network having switching nodes and transmission links to establish a chain-like connection pattern between said teleconference users such that each telephone set is connected to an adjacent set allowing each user to communicate with an adjacent user.

3. A method as defined in claim 2 wherein said communications network is instructed to establish a chain-like connection pattern between said teleconference users by connecting the telephone set of a user to a telephone set of a first adjacent teleconference user via a first logical channel and to the telephone set of a second adjacent teleconference user via a second logical channel.

4. A method as defined in claim 3 further comprising the steps of encrypting the transmitted calls of each of said first and second logical channels, thereby providing an outgoing secure call from one user to each adjacent user and decrypting each incoming secure call once received at each user via said first and second logical channels, such that a secure teleconference network is provided between teleconference users.

5. A method of providing a teleconference call between a number of users, comprising the steps of:

instructing a communications network having switching nodes and transmission links to establish a chain-like connection pattern between said users, by connecting the telephone set of a user to the telephone set of a first adjacent user via a first logical channel and to the telephone set of a second adjacent user via a second logical channel;

receiving a first incoming signal from a first adjacent teleconference user via a first logical channel;

decoding said first incoming signal to provide a first incoming speech signal;

forwarding said first incoming speech signal to a first input of a signal processing circuit means;

receiving a second incoming signal from a second adjacent teleconference user via a second logical channel;

decoding said second incoming signal to provide a second incoming speech signal;

forwarding said second incoming speech signal to a second input of said signal processing circuit means;

detecting the presence of and decoding a user'"'"'s output speech signal from an output of user interface means;

forwarding said output speech signal if present to a third input of said signal processing circuit means;

summing said speech signals of said first and second inputs at said signal processing means and forwarding the summed signal to an input of code translation circuit means for conversion and forwarding to an input of said user interface means;

summing said speech signals of said second and third inputs at said signal processing means to provide a first outgoing speech signal;

coding said first outgoing speech signal to provide a first outgoing signal;

transmitting said first outgoing signal to said first adjacent user via said first logical channel;

summing said speech signals of said first and third inputs at said signal processing circuit means to provide a second outgoing speech signal;

coding said second outgoing speech signal to provide a second outgoing signal; and

transmitting said second outgoing signal to said second adjacent user via said second logical channel.

6. A method as defined in claim 5 further comprising the steps of encrypting the transmitted calls of each of said first and second logical channels, thereby providing an outgoing secure call from one user to each adjacent user and decrypting each incoming secure call once received at each user via said first and second logical channels, such that a secure teleconference network is provided between teleconference users.

7. A method of bridging teleconference calls at each telephone set used within a secure teleconference network, comprising the steps of:

receiving a first incoming secure signal from a first adjacent teleconference user via a first logical channel;

decrypting said first incoming secure signal;

decoding said decrypted first incoming signal to provide a first incoming speech signal;

forwarding said first incoming speech signal to a first input of a signal processing circuit means;

receiving a second incoming signal from a second adjacent teleconference user via a second logical channel;

decoding said second incoming signal to provide a second incoming speech signal;

forwarding said second incoming speech signal to a second input of said signal processing circuit means;

detecting the presence of and decoding a user'"'"'s output speech signal from an output of user interface means;

forwarding said output speech signal if present to a third input of said signal processing circuit means;

summing said speech signals of said first and second inputs at said signal processing means and forwarding the summed signal to an input of code translation circuit means for conversion and forwarding to an input of said user interface means;

summing said speech signals of said second and third inputs at said signal processing means to provide a first outgoing speech signal;

coding said first outgoing speech signal to provide a first outgoing signal;

encrypting said first outgoing signal to provide a first outgoing secure signal;

transmitting said first outgoing secure signal to said first adjacent user via said first logical channel;

summing said speech signals of said first and third inputs at said signal processing circuit means to provide a second outgoing speech signal;

coding said second outgoing speech signal to provide a second outgoing signal;

encrypting said second outgoing signal to provide a second outgoing secure signal; and

transmitting said second outgoing secure signal to said second adjacent user via said second logical channel.

8. A method as defined in claim 7 further comprising the step of instructing a communications network having switching nodes and transmission links to establish a chain-like connection pattern between said teleconference users such that each telephone set is connected to an adjacent set allowing each user to communicate with an adjacent user.

9. A method as defined in claim 8 wherein said communications network is instructed to establish a chain-like connection pattern between said teleconference users by connecting the telephone set of a user to a telephone set of a first adjacent teleconference user via said first logical channel and to the telephone set of a second adjacent teleconference user via said second logical channel.

10. A method of providing a secure teleconference call between a number of users, comprising the steps of:

instructing a communications network having switching nodes and transmission links to establish a chain-like connection pattern between said users, thereby allowing each user to communicate with an adjacent user;

receiving a first incoming secure signal from a first adjacent teleconference user via a first logical channel;

decrypting said first incoming secure signal;

decoding said decrypted first incoming signal to provide a first incoming speech signal;

forwarding said first incoming speech signal to a first input of a signal processing circuit means;

receiving a second incoming signal from a second adjacent teleconference user via a second logical channel;

decoding said second incoming signal to provide a second incoming speech signal;

forwarding said second incoming speech signal to a second input of said signal processing circuit means;

detecting the presence of and decoding a user'"'"'s output speech signal from an output of user interface means;

forwarding said output speech signal if present to a third input of said signal processing circuit means;

summing said speech signals of said first and second inputs at said signal processing means and forwarding the summed signal to an input of code translation circuit means for conversion and forwarding to an input of said user interface means;

summing said speech signals of said second and third inputs at said signal processing means to provide a first outgoing speech signal;

coding said first outgoing speech signal to provide a first outgoing signal;

encrypting said first outgoing signal to provide a first outgoing secure signal;

transmitting said first outgoing secure signal to said first adjacent user via said first logical channel;

summing said speech signals of said first and third inputs at said signal processing circuit means to provide a second outgoing speech signal;

coding said second outgoing speech signal to provide a second outgoing signal;

encrypting said second outgoing signal to provide a second outgoing secure signal; and

transmitting said second outgoing secure signal to said second adjacent user via said second logical channel.

11. A method as defined in claim 10 wherein said communications network is instructed to establish a chain-like connection pattern between said teleconference users by connecting the telephone set of a user to a telephone set of a first adjacent teleconference user via said first logical channel and to the telephone set of a second adjacent teleconference user via said second logical channel.

12. A method of bridging teleconference calls at each telephone set used within a teleconference network, comprising the steps of:

receiving an incoming call having multiplexed first and second signals from a communications network having switching nodes and transmission links;

demultiplexing said incoming call to provide said first and second signals;

decoding said first and second calls to provide first and second incoming speech signals;

summing said first and second incoming speech signals and forwarding the sum to a user interface;

detecting the presence of an output speech signal from said user interface;

summing said first incoming speech signal with said output speech signal to provide a first outgoing speech signal;

summing said second incoming speech signal with said output speech signal to provide a second outgoing speech signal;

coding said first and second outgoing speech signals to provide first and second outgoing signals;

multiplexing said first and second outgoing signals; and

transmitting said multiplexed outgoing signals via a channel to said communications network for connection to other teleconference users.

13. A method as defined in claim 12 further comprising the steps of encrypting said first and second outgoing signals, thereby providing first and second outgoing secure signals and decrypting first and second incoming secure signals, such that a secure teleconference network is provided between teleconference users.

14. A method as defined in claim 13 further comprising the steps of:

instructing conference control means to demultiplex said transmitted outgoing signals from each of said teleconference user once received at said communications network to provide a first and second signal;

instructing conference control means to establish a chain-like connection pattern with said first and second signals, between said teleconference users, such that each telephone set is connected to an adjacent set allowing each user to communicate with an adjacent user;

multiplexing said first and second signals that have been channelled for a particular teleconference user; and

transmitting said multiplexed signals to said particular teleconference user via said communications network.

15. A telephone set useable for bridging conference calls when used within a teleconference network, comprising:

means for decoding a first incoming signal to provide a first incoming speech signal;

means for decoding a second incoming signal to provide a second incoming speech signal;

user interface means having an input and an output;

means for detecting the presence of and decoding a user'"'"'s output speech signal from the output of said user interface means;

signal processing circuit means having a first and a second input for receiving said first and second incoming speech signal and a third input for receiving said output speech signal;

first means at said signal processing means for summing said first and second speech signals to provide a first summed signal;

code translation circuit means for conversion of said first summed signal and for forwarding to the input of said user interface means;

second means at said signal processing means for summing said speech signals of said second and third inputs to provide a first outgoing speech signal;

first means for coding said first outgoing speech signal to provide a first outgoing signal for transmission to a first adjacent user;

third means at said signal processing means for summing said speech signals of said first and third inputs to provide a second outgoing speech signal; and

second means for coding said second outgoing speech signal to provide a second outgoing signal for transmission to a second adjacent user.

16. A telephone set as defined in claim 15 wherein said decoding means is provided with a first and second input means for receiving a first and second incoming call from a first and second teleconference user via a first and second logical channel and a first and second output means for providing a first and second incoming speech signal.

17. A telephone set as defined in claim 16 wherein said coding means is provided with a first and second input means for receiving a first and second outgoing speech signal and a first and second output means for providing a first and second outgoing call for transmission to a first and second teleconference user via said first and second logical channels.

18. A telephone set as defined in claim 17 wherein said first summing means comprises a first adder adapted to add the incoming speech signals from said first and second outputs of said decoding means, said first adder having an output connected to the input of said user interface.

19. A telephone set as defined in claim 18 wherein said second summing means further comprises a second adder adapted to add the incoming speech signal from the first output of said decoding means to the outgoing speech signal of said user interface, said second adder having an output connected to the second input of said coding means for transmission from the second output thereof to said second teleconference user via said second logical channel.

20. A telephone set as defined in claim 19 wherein said summing means further comprises a third adder adapted to add the incoming speech signal from the second output of said decoding means to the outgoing speech signal of said user interface, said third adder having an output connected to the first input of said coding means for transmission from the first output thereof to said first teleconference user via said first logical channel.

21. A telephone set as defined in claim 20 further comprising switching network means for establishing a chain-like connection pattern between teleconference users, such that each user communicates with a user of an adjacent set, each input and each output of said decoding and coding means respectively, being connected to said network means.

22. A telephone set as defined in claim 21 further comprising conference control means for requesting, setting-up and supervising the interconnection of said teleconference users through said switching network means.

23. A telephone set as defined in claim 22 further comprising encrypting means connected at the output of said coding means for encrypting said outgoing call to provide an outgoing secure call and decrypting means connected at the input of said decoding means for decrypting an incoming secure call.

24. A teleconference network for interconnecting a number of telephone sets, comprising:

communications network means having switching nodes and transmission links for establishing a chain-like connection pattern between said telephone sets, such that each teleconference user communicates with a user of an adjacent set;

each telephone set being comprised of;

means for decoding a first incoming signal to provide a first incoming speech signal;

means for decoding a second incoming signal to provide a second incoming speech signal;

user interface means having an input and an output;

means for detecting the presence of and decoding a user'"'"'s output speech signal from the output of said user interface means;

signal processing circuit means having a first and a second input for receiving said first and second incoming speech signals and a third input for receiving said output speech signal;

first means at said signal processing means for summing said first and second speech signals to provide a first summed signal;

code translation circuit means for conversion of said first summed signal and for forwarding to the input of said user interface means;

second means at said signal processing means for summing said speech signals of said second and third inputs to provide a first outgoing speech signal;

first means for coding said first outgoing speech signal to provide a first outgoing signal for transmission to a first adjacent user;

third means at said signal processing means for summing said speech signals of said first and third inputs to provide a second outgoing speech signal; and

second means for coding said second outgoing speech signal to provide a second outgoing signal for transmission to a second adjacent user;

and conference control means for requesting, setting-up and supervising interconnections of said telephone sets through said communications network means.

25. A teleconference network as defined in claim 24 wherein said decoding means is provided with a first and second input means for receiving a first and second incoming call from a first and second teleconference user via a first and second logical channel and a first and second output means for providing a first and second incoming speech signal.

26. A teleconference network as defined in claim 25 wherein said coding means is provided with a first and second input means for receiving a first and second outgoing speech signal and a first and second output means for providing a first and second outgoing call for transmission to a first and second teleconference user via said first and second logical channels.

27. A teleconference network as defined in claim 26 wherein said first summing means comprises a first adder adapted to add the incoming speech signals from said first and second outputs of said decoding means, said first adder having an output connected to the input of said user interface.

28. A teleconference network as defined in claim 27 wherein said second summing means further comprises a second adder adapted to add the incoming speech signal from the first output of said decoding means to the outgoing speech signal of said user interface, said second adder having an output connected to the second input of said coding means for transmission from the second output thereof to said second teleconference user via said second logical channel.

29. A teleconference network as defined in claim 28 wherein said third summing means further comprises a third adder adapted to add the incoming speech signal from the second output of said decoding means to the outgoing speech signal of said user interface, said third adder having an output connected to the first input of said coding means for transmission from the first output thereof to said first teleconference user via said first logical channel.

30. A teleconference network as defined in claim 29 further comprising encrypting means connected at the output of said coding means for encrypting said outgoing call to provide an outgoing secure call and decrypting means connected at the input:

of said decoding means for decrypting an incoming secure call.

31. A telephone set useable for bridging secure teleconference calls when used in a teleconference network, comprising:

means for decrypting a first incoming secure call from a first teleconference user to provide a first incoming signal;

means for decoding said first incoming signal to provide a first incoming speech signal;

means for decrypting a second incoming secure call from a second teleconference user to provide a second incoming signal;

means for decoding said second incoming signal to provide a second incoming speech signal;

user interface means having an input and an output;

means for detecting the presence of and decoding a user'"'"'s output speech signal from the output of said user interface means;

signal processing circuit means having a first and a second input for receiving said first and second incoming speech signal and a third input for receiving said output speech signal;

first means at said signal processing means for summing said first and second speech signals to provide a first summed signal;

code translation circuit means for conversion of said first summed signal and for forwarding to the input of said user interface means;

second means at said signal processing means for summing said speech signals of said second and third inputs to provide a first outgoing speech signal;

first means for coding said first outgoing speech signal to provide a first outgoing signal;

means for encrypting said first outgoing signal to provide an outgoing secure call for transmission to another teleconference user;

third means at said signal processing means for summing said speech signals of said first and third inputs to provide a second outgoing speech signal;

second means for coding said second outgoing speech signal to provide a second outgoing signal for transmission to a second adjacent user; and

means for encrypting said second outgoing signal to provide an outgoing secure call for transmission to another teleconference user.

32. A telephone set as defined in claim 31 wherein said decrypting means is provided with a first and second input means for receiving a first and second incoming secure call from a first and second teleconference user via a first and second logical channel and a first and second output means for providing a first and second incoming call.

33. A telephone set as defined in claim 32 wherein said encrypting means is provided with a first and second input means for receiving a first and second outgoing call and a first and second output means for providing a first and second outgoing secure call for transmission to a first and second teleconference user via said first and second logical channels.

34. A telephone set as defined in claim 33 wherein said decoding means is provided with a first and second input means for receiving said first and second incoming calls from said first and second output means of said decrypting means and a first and second output means for providing a first and second speech signal.

35. A telephone set as defined in claim 34 wherein said coding means is provided with a first and second input means for receiving a first and second outgoing speech signal and a first and second output means connected to said first and second input means of said encrypting means for providing a first and second outgoing call.

36. A telephone set as defined in claim 35 wherein said first summing means comprises a first adder adapted to add the incoming speech signals from said first and second outputs of said decoding means, said first adder having an output connected to the input of said user interface.

37. A telephone set as defined in claim 36 wherein said second summing means further comprises a second adder adapted to add the incoming speech signal from the first output of said decoding means to the outgoing speech signal of said user interface, said second adder having an output connected to the second input of said coding means for transmission from the second output thereof to the second input of said encrypting means.

38. A telephone set as defined in claim 37 wherein said third summing means further comprises a third adder adapted to add the incoming speech signal from the second output of said decoding means to the outgoing speech signal of said user interface, said third adder having an output connected to the first input of said coding means for transmission from the first output thereof to the first input of said encrypting means.

39. A telephone set as defined in claim 38 further comprising communications network means having switching nodes and transmission links for establishing a chain-like connection pattern between teleconference users, such that each user communicates with a user of an adjacent set, each input and each output of said decoding and coding means respectively, being connected to said network means.

40. A telephone set as defined in claim 39 further comprising conference control means for requesting, setting-up and supervising the interconnection of said teleconference users through said communications network means.

41. A secure teleconference network for interconnecting a number of secure telephone sets, comprising:

communications network means having switching nodes and transmission links for establishing a chain-like connection pattern between said secure telephone sets, such that each teleconference user communicates with a user of an adjacent set;

each secure telephone set being comprised of;

means for decrypting a first incoming secure call from a first teleconference user to provide a first incoming signal;

means for decoding said first incoming signal to provide a first incoming speech signal;

means for decrypting a second incoming secure call from a second teleconference user to provide a second incoming signal;

means for decoding said second incoming signal to provide a second incoming speech signal;

user interface means having an input and an output;

means for detecting the presence of and decoding a user'"'"'s output speech signal from the output of said user interface means;

signal processing circuit means having a first and a second input for receiving said first and second incoming speech signal and a third input for receiving said output speech signal;

first means at said signal processing means for summing said first and second speech signals to provide a first summed signal;

code translation circuit means for conversion of said first summed signal and for forwarding to the input of said user interface means;

second means at said signal processing means for summing said speech signals of said second and third inputs to provide a first outgoing speech signal;

first means for coding said first outgoing speech signal to provide a first outgoing signal;

means for encrypting said first outgoing signal to provide an outgoing secure call for transmission to another teleconference user;

third means at said signal processing means for summing said speech signals of said first and third inputs to provide a second outgoing speech signal;

second means for coding said second outgoing speech signal to provide a second outgoing signal for transmission to a second adjacent user;

means for encrypting said second outgoing signal to provide an outgoing secure call for transmission to another teleconference user;

and conference control means for requesting, setting-up and supervising the interconnections of said secure telephone sets through said communications network means.

42. A secure teleconference network as defined in claim 41 wherein said decrypting means is provided with a first and second input means for receiving a first and second incoming secure call from a first and second teleconference user via a first and second logical channel and a first and second output means for providing a first and second incoming call.

43. A secure teleconference network as defined in claim 42 wherein said encrypting means is provided with a first and second input means for receiving a first and second outgoing call and a first and second output means for providing a first and second outgoing secure call for transmission to a first and second teleconference user via said first and second logical channels.

44. A secure teleconference network as defined in claim 43 wherein said decoding means is provided with a first and second input means for receiving said first and second incoming calls from said first and second output means of said decrypting means and a first and second output means for providing a first and second speech signal.

45. A secure teleconference network defined in claim 44 wherein said coding means is provided with a first and second input means for receiving a first and second outgoing speech signal and a first and second output means connected to said first and second input means of said encrypting means for providing a first and second outgoing call.

46. A secure teleconference network as defined in claim 45 wherein said first summing means comprises a first adder adapted to add the incoming speech signals from said first and second outputs of said decoding means, said first adder having an output connected to the input of said user interface.

47. A secure teleconference network as defined in claim 46 wherein said second summing means further comprises a second adder adapted to add the incoming speech signal from the first output of said decoding means to the outgoing speech signal of said user interface, said second adder having an output connected to the second input of said coding means for transmission from the second output thereof to the second input of said encrypting means.

48. A secure teleconference network as defined in claim 47 wherein said third summing means further comprises a third adder adapted to add the incoming speech signal from the second output of said decoding means to the outgoing speech signal of said user interface, said third adder having an output connected to the first input of said coding means for transmission from the first output thereof to the first input of said encrypting means.

49. A telephone set useable for bridging conference calls when used in a teleconference network, comprising:

means for demultiplexing an incoming call having multiplexed first and second signals received from a communications network having switching nodes and transmission links;

means for decoding said first and second incoming signals to provide a first and second incoming speech signal;

first means for summing said first and second incoming speech signals;

user interface means having input means for receiving said incoming speech signals;

means for detecting the presence of an outgoing speech signal from an output of said user interface means;

second means for summing said first incoming speech signal with said outgoing speech signal to provide a first outgoing speech signal;

third means for summing said second incoming speech signal with said outgoing speech signal to provide a second outgoing speech signal;

means for coding said first and second outgoing speech signals to provide a first and second outgoing signal; and

means for multiplexing said first and second outgoing signals for transmission via a logical channel to a switching network for channelling to another teleconference user.

50. A telephone set as defined in claim 49 further comprising means for encrypting said first and second outgoing signals, thereby providing first and second outgoing secure signals and means for decrypting first and second incoming secure signals, such that a secure teleconference network is provided between teleconference users.

51. A telephone set as defined in claim 50 further comprising:

conference control means for demultiplexing said transmitted outgoing signals from each of said teleconference user once received at said switching network to provide a first and second network signal, for establishing a chain-like connection pattern of said network signals, between said teleconference users, such that each telephone set is connected to an adjacent set allowing each user to communicate with an adjacent user, for multiplexing network signals that have been channelled for a particular teleconference user, and for transmitting said multiplexed network signals to said particular teleconference user via said switching network.