Satellite communication system and method with message authentication suitable for use in financial institutions

• US 4,860,352 A
• Filed: 05/20/1985
• Issued: 08/22/1989
• Est. Priority Date: 05/20/1985
• Status: Expired due to Fees

• Current Assignee: Satellite Financial Systems Corporation
• Original Assignee: Satellite Financial Systems Corporation
• Inventors: Stewart, Walter M., Laurance, Joel E.
• Primary Examiner(s): Cangialosi, Salvalore
• Assistant Examiner(s): GREGORY, BERNARR E
• Application Number:
  US06/736,093
• Time in Patent Office: 1,555 Days
• Field of Search: 178/22.08, 178/22.09, 178/22.17, 343/357, 343/6.5 LC, 380/28, 380/48, 380/24, 380/25, 342/357, 342/455, 342/42, 342/44, 342/45, 342/46, 342/50, 342/450, 342/451, 342/454, 342/457, 342/463, 342/465, 340/825.34, 455/3, 455/5, 455/12, 364/408, 364/449
• US Class Current: 380/258
• CPC Class Codes: G01S 19/00 Satellite radio beacon positioning systems; Determining position, velocity or attitude using signals transmitted by such systems
• CPC Class Codes: G06Q 20/3224 Transactions dependent on location of M-devices
• CPC Class Codes: G06Q 20/382 insuring higher security of transaction
• CPC Class Codes: G06Q 20/40 Authorisation, e.g. identification of payer or payee, verification of customer or shop credentials; Review and approval of payers, e.g. check credit lines or negative lists
• CPC Class Codes: H04L 2209/56 Financial cryptography, e.g. electronic payment or e-cash
• CPC Class Codes: H04L 2209/80 Wireless network architectures or network communication protocols for wireless network security H04W12/00
• CPC Class Codes: H04L 9/002 Countermeasures against attacks on cryptographic mechanisms network architectures or network communication protocols for protection against malicious traffic H04L63/1441
• CPC Class Codes: H04L 9/3215 using a plurality of channels network architectures or network communication protocols using different networks H04L63/18
• CPC Class Codes: H04L 9/3271 using challenge-response

Abstract

A satellite communications system apparatus and method for authenticating data transmissions uses the position of the transmitter, which position is determined by the satellite communications system. The transmitter position information is appended to the message (which can be either clear text or encrypted), which is sent to the receiver at a second location by the satellite system. A receiver can then authenticate the received message by comparing the received transmitter position with stored transmitter position information. The mobile transceiver syncing versions of the present invention allow the transceiver to be mobile, as opposed to being stationary. In this mobile version, each succeeding message is encrypted using the previous position of the mobile transceiver. Examples of transceivers implementing the apparatus and method of the present invention are shown, as are the specific vertical market applications of financial networks and automatic weather observation and reporting systems. In each version of the present invention, the determination of the location of the transmitter for each message that is received introduces an independently verifiable authentication parameter.

Claims

1. A radio communication system for communicating an authorized user message from a first transmitting antenna location to a second receiving antenna location, which comprises:

(a) first means for transmitting the authorized user message from the first antenna location;

(b) transmission source location system means comprising;

(1) message receiving means for receiving the authorized user message form said first means,

(2) position determining means for determining the actual position of the first antenna location by receiving the authorized user message over a plurality of difference communication paths to produce by triangulation transmitter position data from the differences between the communication paths, and

(3) retransmitting means for transmitting over the same communication channel the authorized user message having said transmitter position data appended thereto; and

(c) second means at the second location comprising;

(1) utilization means for receiving from said transmission source location system means the authorized user message with said transmitter position data appended thereto, and

(2) means for comparing said transmitter positioned data with an authorized position data to authenticate the authorized user message received from said transmission source location system means, whereby the determination of said transmitter antenna position data by said transmission source location system means introduces an independently verifiable message authentication parameter.

2. The system of claim 1,

wherein said first means further comprises encryption means for encrypting the authorized user message using position data indicative of the first location to produce an encrypted authorized user message,

wherein said first means transmits said encrypted authorized user message;

wherein said message receiving means receives said encrypted authorized user message from said first means;

wherein said position determining means determines the actual position of said first means by receiving said encrypted authorized user message;

wherein said retransmitting means transmits said encrypted authorized user message with said transmitter position data appended thereto;

wherein said utilization means for receiving receives said encrypted authorized user message with said transmitter position data appended thereto from said retransmitting means;

wherein said means for comparing compares said transmitter position data with said authorized position data to authenticate said encrypted authorized user message received from said retransmitting means; and

wherein said second means further comprises decryption means, responsive to said means for receiving and said means for comparing, for decrypting the authenticated encrypted authorized user message using either said transmitter position data or said authorized position data.

3. The system as defined in claim 1,

wherein said first means further comprises encryption means for encrypting the authorized user message using a non-position element to produce an encrypted authorized user message;

wherein said first means transmits said encrypted authorized user message;

wherein said message receiving means receives said encrypted authorized user message from said first means;

wherein said position determining means determines the actual position of said first means by receiving said encrypted authorized user message;

wherein said retransmitting means transmits said encrypted authorized user message with said transmitter position data appended thereto;

wherein said means for receiving receives said encrypted authorized user message with said transmitter position data appended thereto from said retransmitting means;

wherein said means for comparing compares said transmitter position data with said authorized position data to authenticate said encrypted authorized user message received from said retransmission means; and

wherein said second means further comprises decryption means, responsive to said means for receiving and said means for comparing, for decrypting the authenticated encrypted authorized user message using said non-position element.

4. The system as defined in claim 1,

wherein said first means further comprises encryption means for encrypting the authorized user message using position data indicative of the first location and a non-position element to produce an encrypted authorized user message;

wherein said first means transmits said encrypted authorized user message;

wherein said message receiving means receives said encrypted authorized user message from said first means;

wherein said position determining means determines the actual position of said first means by receiving said encrypted authorized user message;

wherein said retransmitting means transmits said encrypted authorized user message with said transmitter position data appended thereto;

wherein said means for receiving receives said encrypted authorized user message with said transmitter position data appended thereto from said retransmitting means;

wherein said means for comparing compares said transmitter position data with said authorized position data to authenticate said encrypted authorized users message received from said retransmitting means; and

wherein said second means further comprises decryption means, responsive to said means for receiving and said means for comparing, for decrypting the authenticated encrypted authorized user message using said non-position element and either said transmitter position data or said authorized user position data.

5. The system as defined in any one of claims 1 through 4, wherein said position determining means of said transmission source location system means comprises:

at least three satellites communicating with a ground station, wherein said ground station calculates the position of said first means by comparison of the time taken for the authorized user message to travel between said first means and said satellites, and transmits said authorized user messages with said transmitter position data appended thereto to one of said satellites for transmission to said second means.

6. A method for transmitting an authorized user message from a first transmitter location to a second receiver location, comprising the steps of:

(a) transmitting the authorized user message from the first location;

(b) receiving the authorized user message by a transceiver system;

(c) determining at said transceiver system the position of the first location by receiving the authorized user messages by triangulation over a plurality of different communication paths to produce therefrom transmitter position data accurately defining the transmission site;

(d) appending at said transceiver system the transmitter position data to the authorized user message;

(e) retransmitting the authorized user message and said transmitter position data over a common communication channel;

(f) receiving said authorized user message and said transmitter position data at said second location; and

(g) comparing at said second location said transmitter position data with an authorized position data to authenticate the authorized user message, whereby the determination of said transmitter position data by said transceiver system introduces an independently verifiable message authentication parameter.

7. The method of claim 6, comprising the additional steps of:

encrypting at said first location the authorized user message using position data indicative of the first location to produce an encrypted authorized user message; and

wherein said transceiver system receives said encrypted authorized user message, determines the position of the first location by receiving said encrypted authorized user message to produce said transmitter position data, and appends said transmitter position data to said encrypted authorized user message; and

decrypting the authenticated encrypted authorized user message using either said transmitter position data or said authorized position data.

8. The method of claim 6, comprising the additional steps of:

encrypting said authorized user message prior to transmission using a non-position element to produce an encrypted authorized user message;

wherein said transceiver system receives said

encrypted authorized user message, determines the position of the first location by receiving said authorized user message to produce said transmitter position data, appends said transmitter position data to said encrypted authorized user message, and transmits the same; and

decrypting the received authorized user message after authentication thereof using said non-position element.

9. The method of claim 6 comprising the additional steps of:

encrypting at said first location said authorized user message using position data indicative of the first location and a non-position element to produce an encrypted authorized user message;

wherein said transceiver system receives said encrypted authorized user message, determines the position of the first location by receipt of said authorized user message to produce said transmitter position data, appends said transmitter position data to said encrypted authorized user message, and transmits the same; and

decrypting at said second location said encrypted authorized user message after authentication thereof using said non-position element and either said transmitter position data or said authorized position data.

10. The method of any of claims 6 through 9, wherein said transceiver system comprises at least three satellites and a ground station, and said ground station performs said step of determining the position of said first location by comparison of the time taken for authorized user messages to reach said satellites from said first location in order to produce said transmitter position data, and transmits said transmitter position data to one of said satellites.

11. A radio transceiver for communicating with a position determining system for establishing the position of a transmitted signal by triangulation from radio signals comparing the transmission time thereof over different paths, said transceiver comprising:

means for constructing a first authorized user message and transmitting it to the position determining system for appending thereto transceiver position data and forming thereby a second authorized user message;

means for receiving said second authorized user message with a transceiver position data appended thereto from the position determining system, said transceiver position data indicative of the position of the transceiver which transmitted said first authorized user message;

means for extracting said transceiver position data from said second authorized user message received from said position determining system;

means for comparing said extracted transceiver position data with authorized position data; and

means for authenticating said authorized user message responsive to said means for comparing.

12. The transceiver of claim 11, further comprising means for encrypting said first authorized user message prior to transmission thereof using transceiver position data indicative of the location of said transceiver, and

means for decrypting said second authorized user message received from said position determining system using either transceiver position data appended to said second authorized user message by the satellite system or said authorized position data.

13. The transceiver of claim 11, further comprising means for encrypting said first authorized user message prior to transmission thereof using a non-position element;

and

means for decrypting said second authorized user message received from said position determining system using a stored non-position element.

14. The transceiver of claim 11, further comprising:

means for encrypting said first authorized user message prior to transmission to said position determining system using said transceiver position data and a non-position element to produce an encrypted message prior to transmission to said satellite system; and

means to decrypt said second authorized user message received from said position determining system using said non-position element and either said transceiver position data or said authorized position data.

15. A transceiver for communicating with a satellite system, said satellite system being of the type comprising at least three satellites in communication with a ground station, said satellite system comprising means for determining the position of a transceiver communicating therewith by comparison of the time taken for authorized user messages to reach said satellites by different communication paths from a single transceiver location and to append transceiver position data indicative of the location of said transceiver to second authorized user messages transmitted by said transceiver, said transceiver comprising:

means for constructing a first authorized user message;

means for transmitting said first authorized user message;

means for receiving a second authorized user message from said satellite system; and

a message authentication system comprising means for extracting said transceiver position data appended by said satellite system to said second authorized user message concerning the location of the transmitter of said second authorized user message;

means for comparing said extracted transceiver position data to an authorized position data; and

means for authenticating said second authorized user message based on said comparison of said extracted position data and said authorized position data.

16. The transceiver of claim 15, wherein said transceiver further comprises:

means for encrypting a first authorized user message prior to transmission thereof using a position data indicative of the location of said transceiver; and

means for decrypting said second authorized user message received from said satellite system using either said transceiver position data or said authorized position data.

17. The transceiver of claim 15, wherein said transceiver further comprises:

means for encrypting a first authorized user message prior to transmission using a non-position element; and

means for decrypting said second authorized user message received from said satellite system using said non-position element.

18. The transceiver of claim 15, further comprising:

means for encrypting a first authorized user message prior to transmission using a position data indicative of the location of said transceiver and using a non-position element; and

means for decrypting said second authorized user message received from said satellite system using said non-position element and either said transceiver position data or said authorized position data.

19. A system for communicating authorized user messages from a previous position and a present position to a second location, which comprises:

(a) mobile transceiver means located at a present position, comprising;

(1) means for storing a previous position data indicative of the previous position of said mobile transceiver means, said previous position data having been received from satellite system means;

(2) sender request means for transmitting a sender request to said satellite system means;

(3) means for receiving said sender request with present position data appended thereto from said satellite system means;

(4) means for storing said received present position data;

(5) encryption means for encrypting an authorized user message using said previous position data to produce an encrypted authorized user message, and

(6) transmitter means for transmitting said encrypted authorized user message to said satellite system means;

(b) satellite system means, which comprises;

(1) first means for receiving said sender request from said mobile transceiver;

(2) position determining means for determining by triangulation the actual position of the mobile transceiver by receiving said sender request therefrom from different communication paths to determine said present position data;

(3) second means for transmitting said sender request with said present position data appended thereto to said mobile transceiver;

(4) third means for receiving said encrypted authorized user message from said mobile transceiver;

(5) fourth means for appending said present position data to said encrypted authorized user message; and

(6) fifth means for transmitting said encrypted authorized user message with said present position data appended thereto to receiver means; and

(c) receiver means located at the second location, which comprises;

(1) means for receiving said encrypted authorized user message with said present position data appended thereto from said satellite system means;

(2) means for storing said present position data; and

(3) means for decrypting said encrypted authorized user message using said previous position data.

20. The system of claim 19, wherein said mobile transceiver means further comprises means for encrypting said authorized user message using said previous position data and a non-position element, and said receiver means further comprises means for decrypting said encrypted authorized user message using said previous position data and said non-position element.

21. The system of either of claims 19 or 20, wherein said satellite system each comprise at least three satellites and a ground station, and wherein said satellites each comprise means for transmitting to said ground station the relative time at which said authorized message is received, and wherein said ground station comprises means for determining the position of said transceiver which transmitted said authorized user messages to said satellites, and means for transmitting said transceiver position data responsive thereto to said satellites.

22. A system for communicating authorized user messages from a previous location and a present location to a remote location, which comprises:

(a) mobile transceiver means located first at said previous location and presently at the present location, comprising;

(1) means for storing a previous position data indicative of the previous position of said mobile transceiver means, said previous position data having been received from satellite system means;

(2) means for encrypting an authorized user message using said previous position data;

(3) means for transmitting said encrypted authorized user message to said satellite system;

(4) means for receiving a present position data from said satellite system means; and

(5) means for storing said received present position data;

(b) satellite system means, comprising;

(1) first means of determining by triangulation the present position of said mobile transceiver means by receiving said encrypted authorized user message from said mobile transceiver means over different paths, and for generating said present transceiver position data responsive to the time of transmission over the different paths; and

(2) means for appending said present transceiver position data to said encrypted authorized user message, and for transmitting to receiver means said encrypted authorized users message with said present transceiver position data appended thereto; and

(c) receiver means, located at the remote location, comprising;

(1) means for receiving from said satellite system means said encrypted authorized user message with said present transceiver position data appended thereto;

(2) means for extracting said present transceiver position data from said encrypted authorized user message and for storing the same; and

(3) means for decrypting said encrypted authorized user message using said previous position data.

23. The system of claim 22, wherein said means for encrypting uses said previous position data and a non-position element, and wherein said means for decrypting uses said previous position data and said non-position element.

24. The system of either of claims 22 or 23, wherein said satellite system comprises at least three satellites and an ground station, wherein said earth station comprises means for determining the location of said mobile transceiver means responsive to the relative time at which said encrypted authorized user messages are received by said satellites, and means for transmitting said location to said satellites.

25. A transceiver for use in connection with a satellite system of the type comprising means for detecting the position of a transmitter of a message, for appending information indicative of the location of said transmitter to said message, and for transmitting the same, said transceiver comprising:

(a) triangulation means for causing said satellite system to determine the position of the transceiver by comparison of signals transmitted over different communication paths and to transmit a first and second present transceiver position data responsive thereto;

(b) means for receiving said first transceiver position data from said satellite system and for storing the same;

(c) means for encrypting a first authorized user message using a first previous transceiver position data;

(d) means for transmitting said first encrypted authorized user message to said satellite system;

(e) means for receiving a second encrypted authorized user message from said satellite system, said satellite system having appended thereto said second present position of the transmitter of said second authorized user message;

(f) means for decrypting said second authorized user message using a second previous position data; and

(g) means for storing said second present position information for use in subsequent decryption of received authorized user messages.

26. The transceiver of claim 25, wherein said means for encrypting said first authorized user message uses said first previous position data and a first non-position element;

and

wherein said means for decrypting said second authorized user message used said second previous position data and a second non-position element.

27. A radio transceiver for use in connection with a satellite system, said satellite system being of the class comprising means for determining by triangulation means the location of a transmitter antenna by processing radio signals communicated over different paths to determine therefrom the location and for transmitting a message indicative of said location, said transceiver comprising:

means for storing a first transceiver position data;

means for combining a first authorized user message with transceiver position data;

means for transmitting the combined position data and authorized user message on a single communication channel;

means for receiving authorized user messages from said satellite system; and

means for authenticating the authorized user messages by comparison with a second transceiver position data at the receiving means.

28. The transceiver of claim 27, including means for encrypting said message with a first non-position key element and said position data.

29. A transceiver for use in connection with a satellite system, said satellite system being of the class comprising at least three satellites and a ground station, said ground station comprising means for determining by the triangulation the location of a transmitter responsive to the relative time taken by a message sent by said transmitter to reach each of said satellites, and said satellite system comprising means for appending present transceiver position data to said message, said transceiver comprising:

means for interrogating the satellite system with a request for information indicative of the transceiver present position;

means for encrypting a first authorized user message based on a first previous position data previously received from the satellite system;

means for storing a first present position data received from said satellite system;

means for transmitting said first encrypted authorized user message encrypted using said first previous position data to said satellite system;

means for receiving a second encrypted authorized user message from said satellite system having appended thereto a second present transceiver position data;

means for extracting said second present transceiver position data from said second encrypted authorized user message; and

means for decrypting said second authorized user message using a second previous position data received from said satellite system.

30. The transceiver of claim 29, wherein said means for encrypting uses a first a non-position element and said first previous transceiver position data, and wherein said means for decrypting uses a second non-position element and said second previous transceiver position data.

31. A transceiver for use in connection with a satellite system of the type comprising at least three satellites and a ground station, said ground station being adapted to determine the position of a transmitter of a given authorized user message responsive to measurement of the relative time taken for the given message to reach the satellites over different communication paths, and for appending that position information to said messages, said transceiver comprising:

means for storing a first present transceiver position data representative of the transmitter position determined by said satellite system;

means for encrypting a first authorized user message incorporating previously stored transceiver position data;

means for transmitting said encrypted first authorized user message to said satellite system;

means for receiving second present transceiver position data from said satellite system and for storing the same;

means for receiving a second encrypted authorized user message from said satellite system; and

means for authenticating said second authorized user message responsive to a second previous position data received from said satellite system.

32. The transceiver of claim 31, wherein said means for encrypting uses a first non-position element and said first previous transceiver position data, and wherein said means for decrypting uses a second non-position element and said second previous transceiver position data.

33. A system for communication of information between remote locations and a central location, said system comprising:

a number of remote terminal means at said remote locations, said remote terminal means each being enabled to accept user input data and each being operatively connected to means for transmitting authorized user messages responsive to said user input data;

a position determining system, comprising means for receiving said authorized user messages and for determining by triangulation from the differences in transmission time from the different remote locations the remote terminal location of a means transmitting the received authorized user message, means for appending the remote terminal location information indicative of the location of said remote terminal means to said authorized user message, and means for transmitting a composite signal of said authorized user message and said remote terminal location information; and

central station means at said central location, said central station means comprising means for receiving said authorized user message transmitted by said position determining system, means for extracting said remote terminal location information from said authorized user message received from said position determining system, means for comparing said remote terminal position information to an authorized terminal position information key, and means for authenticating said authorized user message responsive to matching of the key information with the transmitted location information.

34. The system of claim 33, wherein said positioning determining system comprises a satellite system capable of determining the location of the transmitted messages from said remote locations and said remote terminal means further include means for encrypting said authorized user message prior to transmission thereof to said satellite system, and said central station means further comprises means for decrypting said encrypted authorized user message.

35. The system of claim 34, wherein said encryption is performed using position data indicative of the position of said remote terminal means, and said decryption is performed using either said authorized terminal position information or said terminal position information appended by said satellite system to said encrypted authorized user message.

36. The system of claim 34, wherein said authorized user message is encrypted using a non-position element, and is decrypted using said non-position element.

37. The system of claim 34, wherein said remote terminal means comprises means for encrypting said authorized user message using position information indicative of the location of said remote terminal and a non-position element, and said central station means comprises means for decrypting said encrypted authorized user message using said non-position element and either said authorized terminal position information or position data appended to said encrypted authorized user message by said satellite system.

38. The system of any one of claims 33-37, wherein said position determining system comprises at least three satellites and a control station.

39. A method of communication of information between remote terminal devices and a central processing station, said method comprising the steps of:

at a remote terminal means, assembling an authorized user message;

transmitting said authorized user message to a satellite system;

at said satellite system, detecting by triangulation from the transmission time between the remote terminal devices over different paths to the satellite system the position of a transmitter from which said authorized user message has been received;

combining the detected transmitter position data with said authorized user message and transmitting the combined signals;

at said central station, extracting said transmitter position data from said combined signals;

comparing said extracted transmitter position data to an authorized position data; and

authenticating said authorized user message responsive to said comparison step when the detected position data corresponds to the authorized position data.

40. The method of claim 39, further comprising the steps of encrypting said authorized user message prior to transmission thereof and decrypting said authorized user message after authentication thereof.

41. The method of claim 40, wherein said encryption is performed using position data indicative of the location of said transmitter, and said decryption is performed using either said authorized position data or said extracted position data.

42. The method of claim 40, wherein said encryption is performed using a non-position element, and said decryption is performed using said non-position element.

43. The method of claim 40, wherein said encryption is performed using a non-position element and position data indicative of the location of said transmitter, and said decryption is performed using said non-position element and either said transmitter position data appended to said authorized user message by said satellite system or said authorized position data.

44. The method of any one of claims 39-43, wherein said satellite system is of the type comprising at least three satellites and a control station, and wherein said detection of the position of a transmitter is performed by comparison of the time taken by said authorized user messages to reach said satellites.

45. Method for transmitting data from a mobile transceiver having a previous location and a present location to a second location, comprising the steps of:

(a) at said present location;

(1) receiving present transceiver position data with a satellite system in response to triangulation analysis of signals transmitted from a transmitter site over different communication paths;

(2) storing a former said present transceiver position data to provide previous transceiver position data;

(3) combining with a present authorized user message a stored previous transceiver position; and

(4) transmitting said combined authorized user message;

(b) at said satellite system;

(1) receiving said transmitted combined authorized user message;

(2) further combining present transceiver position data to said combined authorized user message;

(3) transmitting said authorized user message combined with said present transceiver position data; and

(c) at said remote location;

(1) receiving said authorized user message together with said present transceiver position data;

(2) storing said present transceiver position data to provide stored previous transceiver position data; and

(3) authenticating said authorized user message using stored previous transceiver position data.

46. The method of claim 45, comprising the additional step of:

at said present transceiver location;

causing said satellite system to determine and transmit said present transceiver position data.

47. The method of claim 45, wherein said encryption step is additionally performed using a non-position element, and said decryption step is performed using said non-position element.

48. The method of any of claims 45-47, wherein said satellite system is of the type comprising at least three satellites and a control station, said satellite system comprising means for determining the position of the transceiver by comparison of the times taken for a said authorized user message to reach said satellites.

49. In a radio data transmission authentication system including a data message transmitter and data receiving station therefor, the improvement comprising:

an intermediate system adapted to detect by triangulation the location of said transmitter by receiving and timing data transmission messages transmitted by said transmitter over multiple paths to the intermediate system and to formulate a combined signal by combining with the data transmission signal a further signal representative of the detected location of the transmitter;

means for transmitting said combined signal indicative of the transmitter location on a common communication channel to said data receiving station; and

data authentication means at the data receiving station for receiving said combined signal and correlating said further signals representative of the location of the transmitter with a designated position of the transmitter to authentic transmitted data whereby unauthorized communications not sent from an actual authorized location are eliminated so that the authorized location only need be secured against unauthorized communications.

50. A data transmission authentication system, comprising in combination,

source means at a transmission location for introducing and transmitting a message over a communication channel,

message modification means for determining by means of messages transmitted over different paths using triangulation the transmission location and combining with said message for transmission therewith on the same channel a further message identifying the determined transmission location of the source means,

utilization means at a message reception station for receiving the combined message,

a common communication channel for transmitting the message combined with the further message to said utilization means,

authentication means at the message reception station for comparing the further message with locally derived source location data at the reception station, and

means qualifying said message for utilization by the utilization means only upon satisfactory comparison of the further message and the locally derived source location data to assure that the transmission came from its authorized source location.

51. The method of transmitting an authorized user message from a first location to a second location, comprising the steps of:

(a) transmitting the authorized user message from a transmitter at the first location,

(b) identifying the transmitter location from which the message was transmitted by triangulation analysis of the message transmitted over a plurality of paths,

(c) combining with the message an authenticating message derived from the location identified to provide a combined message transmitted over a common transmission channel,

(d) receiving the combined message at a reception station for utilizing the message contents,

(e) authenticating the message contents by verifying an authorized location of the source with the transmitted authenticating message, and

(f) securing the first location against the transmission of unauthorized messages.