Method and apparatus for multi-channel communication security

• US 4,802,220 A
• Filed: 03/20/1985
• Issued: 01/31/1989
• Est. Priority Date: 03/20/1985
• Status: Expired due to Term

• Current Assignee: Bell Telephone Laboratories, Inc. (Nokia Corporation)
• Original Assignee: American Telephone & Telegraph Company (AT&T, Inc.)
• Inventors: Marker, Walter S. Jr.
• Primary Examiner(s): Cangialosi, Salvatore
• Assistant Examiner(s): GREGORY, BERNARR E
• Application Number:
  US06/714,192
• Time in Patent Office: 1,413 Days
• Field of Search: 455/27, 375/2.1, 375/2.2, 370/69.1, 370/60, 370/94, 179/1.5 R, 179/1.5 S, 380/21, 380/31, 380/44, 380/28, 380/33, 380/43, 380/48, 380/23-25, 380/34, 380/49
• US Class Current: 380/33
• CPC Class Codes: H04L 25/14 Channel dividing arrangements , i.e. in which a single bit stream is divided between several baseband channels and reassembled at the receiver
• CPC Class Codes: H04L 63/0428 wherein the data content is protected, e.g. by encrypting or encapsulating the payload
• CPC Class Codes: H04L 63/18 using different networks or channels, e.g. using out of band channels cryptographic mechanisms or cryptographic arrangements for key distribution involving distinctive intermediate devices or communication paths H04L9/0827; cryptographic mechanisms or cryptographic arrangements for authentication using a plurality of channels H04L9/3215
• CPC Class Codes: H04L 9/00 Cryptographic mechanisms or cryptographic arrangements for secret or secure communications; Network security protocols
• CPC Class Codes: H04Q 11/0428 Integrated services digital network, i.e. systems for transmission of different types of digitised signals, e.g. speech, data, telecentral, television signals
• CPC Class Codes: H04Q 2213/13176 Common channel signaling, CCS7
• CPC Class Codes: H04Q 2213/13202 Network termination [NT]
• CPC Class Codes: H04Q 2213/13208 Inverse multiplexing, channel bonding, e.g. TSSI aspects
• CPC Class Codes: H04Q 2213/13209 ISDN
• CPC Class Codes: H04Q 2213/13339 Ciphering, encryption, security

Abstract

A multi-channel communication security system where the information in an original information message is split among a number of channels in accordance with a message splitting routine such that the interception and analysis of any single channel does not compromise the privacy of the communication. The system provides secure communication terminal adapters in cojunction with user terminals for splitting and recombining of private communications together with control facilities in an integrated services digital network (ISDN) for selecting amoung a multiplicity of possible of message splitting routines and generating security code signals for transmission in separate D-channels to the user equipment.

Claims

1. A security arrangement for communicating an information message comprising

a plurality of user stations, and

a digital switching network for selectively establishing communication channels among said plurality of user stations and including control means responsive to a request in a first signalling channel from a first one of said user stations for a secure call to a second one of said user stations both for controlling the establishment by said digital switching network of first and second ones of said communication channels from said first user station through said digital switching network without security processing to said second user station and for selecting a splitting routine from a plurality of message splitting routines said control means being responsive to said selected splitting routine for transmitting in said first signaling channel a first security code signal defining said selected splitting routine to said first user station and transmitting a second security code signal defining a combining routine associated with said selected splitting routine in a second signaling channel to said second user station, said first and second signaling channels each being distinct from said first and second communication channels, said first user station comprising

means responsive to said first security code signal defining said selected splitting routine, for splitting said message into first portions and second portions in accordance with said selected splitting routine, and

means for communicating said first portions and said second portions over said first and second communication channels, respectively, through said digital switching network, and said second user station comprising

means responsive to said second security code signal defining said combining routine and to a receipt of said first portions and second portions from said first and second communication channels, for reforming said message in accordance with said combining routine.

2. A security arrangement in accordance with claim 1 wherein said first and second communication channels are included in separate circuit-switched channels of said digital switching network.

3. A security arrangement in accordance with claim 1 wherein said first and second communication channels are included in separate logical packet-switched channels of said digital switching network.

4. A security arrangement in accordance with claim 1 wherein said first and second communication channels are included in a single logical packet-switched channel of said digital switching network.

5. A security arrangement in accordance with claim 1

wherein said splitting means further comprises

first memory means for storing control information defining the splitting of messages into portions in accordance with a number of splitting routines,

first processor means responsive to said first security code signal for reading from said first memory means control information defining the splitting of messages in accordance with said selected splitting routine, and

means responsive to said control information read from said first memory means, for controlling the splitting of said information message into said first portions and said second portions;

and

wherein said reforming means further comprises

second memory means for storing control information defining the combining of message portions in accordance with a number of combining routines,

7. A security arrangement in accordance with claim 5

wherein said communicating means comprises

means for separately encrypting said first portions and said second portions and

means for transmitting said encrypted first portions and said encrypted second portions over said first and second communication channels, respective, through said digital switching network;

and

wherein said combining means comprises

means for separately decrypting said first portions and said second portions and

means for combining said decrypted first portions and said decrypted second portions to reform said information message.

15. A security arrangement in accordance with claim 1

wherein said message comprises a plurality of bits and

wherein each of said first portions and each of said second portions include at least one of said bits.

16. An arrangement in accordance with claim 1

wherein said communicating means comprises

means for separately encrypting said first portions and said second portions and

means for transmitting said encrypted first portions and said encrypted second portions over said first and second communication channels, respectively, through said digital switching network;

and

wherein said reforming means comprises

means for separately decrypting said first portions and said second portions and

means for combining said decrypted first portions and said decrypted second portions to reform said message.

17. A security arrangement in accordance with claim 15

wherein said means for separately encrypting said first portions and said second portions comprises means for combining first and second random data with said first portions and said second portions, respectively, and

wherein said means for separately decrypting said first portions and said second portions comprises means for removing said first and second random data from said first portions and said second portions, respectively.

18. A security arrangement in accordance with claim 1 further comprising

means for transmitting a special character on both of said first and second communication channels, and

means responsive to a receipt of said special character on both of said first and second communication channels, for enabling said reforming means.

19. A security arrangement in accordance with claim 1

wherein said communicating means is responsive to the initiation by said splitting means of the splitting of said information message into said first portions and said second portions, for transmitting a first character on said first communication channel before transmitting said first portions, and for transmitting a second character on said second communication channel before transmitting said second portions, where said first and second characters may be identical characters, and

wherein said reforming means is responsive to a receipt of said first character on said first communication channel and said second character on said second communication channel, for initiating the reforming of said information message.

20. A security arrangement in accordance with claim 1 wherein said network comprises

a circuit switching network,

wherein said first and second communication channels comprise first and second circuit-switched channels of said circuit switching network.

21. A security arrangement in accordance with claim 19 wherein said first and second circuit-switched channels of said circuit switching network, are transmitted along physically separate paths.

22. A security arrangement in accordance with claim 1 wherein said network comprises

packet transport means,

wherein said first and second channels comprise first and second logical channels through said packet transport means.

23. A security arrangement in accordance with claim 21 wherein said first and second logical channels are transmitted through said packet transport means along physically separate paths.

25. A security arrangement in accordance with claim 23 wherein

said splitting means further comprises

first memory means for storing control information defining the splitting of messages into components in accordance with a number of splitting routines,

first processor means responsive to said first security code signal for reading from said first memory means control information defining the splitting of messages in accordance with said selected splitting routine, and

means responsive to said control information read from said first memory means, for controlling the splitting of said message into said N components;

and

wherein said combining means further comprises

second memory means for storing control information defining the combining of message components in accordance with a number of combining routines,

second processor means responsive to said second security code signal for reading from said second memory means control information defining the combining of message components in accordance with said combining routine associated with said selected splitting routine, and

means responsive to said control information read from said second memory means for controlling the combining of said N components to reform said message.

6. second processor means responsive to said second security code signal for reading from said second memory means control information defining the combining of message portions in accordance with said combining routine,

means responsive to said control information read from said second memory means, for combining said first portions and said second portions to reform said information message.

8. A security arrangement in accordance with claim 6

wherein said means for separately encrypting said first portions and said second portions comprises means for combining first and second random data with said first portions and said second portions, respectively, and

wherein said means for separately decrypting said first portions and said second portions comprises means for removing said first and second random data from said first portions and said second portions, respectively.

9. A security arrangement in accordance with claim 6 further comprising

means for transmitting a special character on both of said first and second communication channels, and

means responsive to a receipt of said special character on both of said first and second communication channels, for enabling said reforming means.

10. A security arrangement in accordance with claim 6

wherein said communicating means is responsive to the initiation by said splitting means of the splitting of said information message into said first portions and said second portions, for transmitting a first character on said first communication channel before transmitting said first portions, and for transmitting a second character on said second channel before transmitting said second communication portions, where said first and second characters may be identical characters, and

wherein said combining means is responsive to a receipt of said first character on said first communication channel and said second communication character on said second channel, for initiating the decrypting and combining of said first portions and said second portions.

11. A security arrangement in accordance with claim 6 wherein said network comprises

a circuit switching network,

wherein said first and second communication channels comprise first and second circuit-switched channels of said circuit switching network.

12. A security arrangement in accordance with claim 10 wherein said first and second circuit-switched channels of said circuit switching network, are transmitted along, physically separate paths.

13. A security arrangement in accordance with claim 6 wherein said network comprises

packet transport means,

wherein said first and second communication channels comprise first and second logical channels through said packet transport means.

14. A security arrangement in accordance with claim 12 wherein said first and second logical channels are transmitted through said packet transport means along physically separate paths.

24. A security arrangement for communicating a message comprising

a plurality of user stations, and

a digital switching network for selectively establishing communication channels among said plurality of user stations and including control means responsive to a request in a first signaling channel from a first one of said user stations for a secure call to a second one of said user stations both for controlling the establishment by said digital switching network of N of said communication channels from said first user station through said digital switching network without security processing to said second user station, N being a positive integer greater than one, and for selecting a splitting routine from a plurality of message splitting routines, said control means being responsive to said selected splitting routine for transmitting in said first signaling channel a first security code signal defining said selected splitting routine to said first user station and transmitting a second security code signal defining a combining routine associated with said selected splitting routine in a second signaling channel to said second user station, said first and second signaling channels each being distinct from said N communication channels, said first user station comprising

means responsive to said first security code signal defining said selected splitting routine, for splitting said message into N components in accordance with said selected splitting routine, and

means for transmitting each of said N components on an associated one of said N communication channels through said digital switching network, and said second user station comprising

means responsive to said second security code signal defining said combining routine and to a receipt of said N components on said N communication channels, for combining said N components in accordance with said combining routine to reform said message.

26. A security arrangement in accordance with claim 24

wherein said means for transmitting each of said N components comprises

means for separately encrypting each of said N components and

means for transmitting each of said N encrypted components on an associated one of said N communication channels;

and

wherein said combining means comprises

means for separately decrypting each of said N received components and

means for combining said N decrypted components to reform said message.

28. A security arrangement in accordance with claim 26

wherein said splitting means further comprises

first memory means for storing control information defining the splitting of individual packets among multiple packets in accordance with a number of packet splitting routines,

first processor means responsive to said first security code signal for reading from said first memory means control information defining the splitting of packets in accordance with said selected splitting routine, and

means responsive to said control information read from said first memory means, for controlling the splitting of each of said N packets among said M packets;

and

wherein said combining means further comprises

second memory means for storing control information defining the combining of information from multiple packets into individual packets in accordance with a number of combining routines,

second processor means responsive to said second security code signal for reading from said second memory means control information defining the combining of information from multiple packets in accordance with said combining routine associated with said selected splitting routine, and

means responsive to said control information read from said second memory means for controlling the combining of said information from each of said M packets to reform each of said N packets.

27. A security arrangement for communicating the information in N packets, N being a positive integer, said arrangement comprising

a plurality of user stations, and

a digital switching network for selectively establishing communication channels among said plurality of user stations and including control means responsive to a request in a first signaling channel from a first one of said stations for a secure call to a second one of said user stations both for controlling the establishment by said digital switching network of at least one of said communication channels from said first user station through said digital switching network without security processing to said second user station and for selecting a splitting routine from a plurality of packet splitting routines, said control means being responsive to said selected splitting routine for transmitting in said first signaling channel a first security code signal defining said selected splitting routine to said first user station and transmitting a second security code signal defining a combining routine associated with said selected splitting routine in a second signaling channel to said second user station, said first and second signaling channels each being distinct from said at least one communication channel, said first user station comprising

means responsive to said first security code signal defining said selected splitting routine, for splitting each of said N packets among M packets in accordance with said selected splitting routine, M being a positive integer greater than one, and

means for transmitting said M packets on said at least one communication channel through said digital switching network, and said second user station comprising

means responsive to said second security code signal defining said combining routine and to a receipt of said M packets on said at least one communication channel, for combining information from each of said M received packets in accordance with said combining routine to reform each of said N packets.

29. A security arrangement in accordance with claim 27

wherein said means for transmitting said M packets comprises

means for separately encrypting each of said M packets and

means for transmitting said M encrypted packets on said at least one communication channel;

and

wherein said combining means comprises

means for separately decrypting each of said M received packets and

means for combining information from said M decrypted packets, to reform each of said N packets.

30. In a switching arrangement for providing switched connections among a plurality of user stations each having a plurality of channels contemporaneously available for communication, a security method of communication a message from an originating one of said user stations to a terminating one of said stations comprising

transmitting, by said originating user station, a request to said switching arrangement for a secure call from said originating user to said terminating user stations,

providing, by said switching arrangement in response to said request, a first connection without security processing between a first one of said channels of said originating user station and a first one of said channels of said terminating user station,

providing, by said switching arrangement in response to said request, a second connection without security processing between a second one of said channels of said originating user station and a second one of said channels of said terminating user station,

selecting, by said switching arrangement in response to said request, a splitting routine from a plurality of message splitting routines,

transmitting, by said switching arrangement, a first security code signal defining said selected splitting routine to said originating user station,

transmitting, by said switching arrangement, a second security code signal defining a combining routine associated with said selected splitting routine to said terminating user station,

splitting by said originating user station in response to said first security code signal, said message into first portions and second portions in accordance with said selected splitting routine,

separately encrypting, by said originating user station, said first portions and said second portions,

transmitting, by said originating user station in its first channel, said encrypted first portions to said first connection,

transmitting, by said originating user station in its second channel, said encrypted second portions to said second connection,

receiving, by said terminating user station in its first channel, said encrypted first portions from said first connection,

receiving, by said terminating user station in its second channel, said encrypted second portions from said second connection,

separately decrypting, by said terminating user station, said received encrypted first portions and said received encrypted second portions and

combining, by said terminating user station in response to said second security code signal, said decrypted first portions and said decrypted second portions in accordance with said combining routine to reform said message.

31. In an arrangement comprising

a first switch serving a first user station,

a first plurality of user channels between said first user station and said first switch,

a second switch serving a second user station and

a second plurality of user channels between said second user station and said second switch,

a security method of communicating a message from said first user station to said second user station,

said first user station transmitting a call request in a given one of said first plurality of channels to said first switch, said call request defining a secure call to said second user station,

said first switch transmitting said call request to said second switch,

a given one of said first and second switches selecting one of a plurality of message splitting routines for splitting said message among predetermined ones of said first plurality of channels each being distinct from said given one of said first plurality of channels,

said given switch transmitting a definition of said selected splitting routine to the other one of said first and second switches,

said first switch transmitting said definition of said selected splitting routine in said given one of said first plurality of channels to said first user station,

said second switch transmitting said definition of said selected splitting routine in a given one of said second plurality of channels to said second user station,

said first and second switches connecting without security processing of information from said predetermined ones of said first plurality of channels to corresponding ones of said second plurality of channels each being distinct from said given one of said second plurality of channels,

said first user station transmitting said message on said predetermined ones of said first plurality of channels in accordance with said selected splitting routine, and

said second user station combining information received on said corresponding ones of said second plurality of channels in accordance with a combining routine that is the inverse of said selected splitting routine.

32. In an arrangement comprising a plurality of user stations, an integrated services digital network for providing digital connections among said user stations, and a plurality of user access lines each connecting an associated one of said user stations with said network, each of said user access lines having at least first and second B-channels and a D-channel thereon, said D-channel being distinct from said first and second B-channels,

a security method of communicating a message from a first one of said user stations having an associated first user access line, to a second one of said user stations having an associated second user access line, said method comprising

said first user station transmitting in the D-channel of said first user access line, a secure call request to said network, said secure call request defining a secure call to said second user station,

said network selecting, in response to said secure call request, one of a plurality of message splitting routines for splitting said message between the first and second B-channels of said first user access line,

said network providing a circuit-switched connection without security processing from said first B-channel of said first user access line to the first B-channel of said second user access line, and providing a circuit-switched connection without security processing from said second B-channel of said first user access line to the second B-channel of said second user access line,

said network transmitting a definition of said selected splitting routine to said first user station in said D-channel of said first user access line, and to said second user station in the D-channel of said second user access line,

said first user station transmitting said message in said first and second B-channels of said first user access line in accordance with said selected splitting routine and

said second user station combining information received in said first and second B-channels of said second user access line in accordance with a combining routine that is the inverse of said selected splitting routine.

33. In an arrangement comprising a plurality of user stations, an integrated services digital network for providing digital connections among said use stations, and a plurality of user access lines each connecting an associated one of said user stations with said network, each of said user access lines having at least a D-channel thereon, said D-channel including a signaling channel and a plurality of logical data channels, said signaling channel being distinct from said logical data channels,

a security method of communicating a message from a first one of said user stations having an associated first user access line, to a second one of said user stations having an associated second user access line, said method comprising

said first user station transmitting in the signaling channel of said first user access line, a secure call request to said network, said secure call request defining a secure call to said second user station,

said network selecting, in response to said secure call request, one of a plurality of message splitting routines for splitting said message among logical data channels of said first user access line,

said network providing packet-switched connections without security processing from said logical data channels of said first user access line to logical data channels of said second use access line,

said network transmitting a definition of said selected splitting routine to said first user station in said signaling channel of said first user access line, and to said second user station in the signaling channel of said second user access line,

said first user station transmitting said message in said logical data channels of said first user access line in accordance with said selected splitting routine and

said second user station combining information received in said logical data channels of said second user access line in accordance with a combining routine that is the inverse of said selected splitting routine.

34. In an arrangement comprising a plurality of user stations, an integrated service digital network for providing digital connections among said user stations, and a plurality of user access lines each connecting an associated one of said user stations with said network, each of said user access lines having at least a D-channel thereon, said D-channel including a signaling channel and at least one logical data channel, said signaling channel being distinct from said logical data channel,

a security method of communicating a message from a first one of said user stations having an associated first user access line, to a second one of said user stations having an associated second user access line, said method comprising

said first user station transmitting in the signaling channel of said first user access line, a secure call request to said network, said secure call request defining a secure call to said second user station,

said network selecting, in response to said secure call request, one of a plurality of message splitting routines for splitting said message among a plurality of packets to be transmitted in a logical data channel of said first user access line,

said network providing a packet-switched connection without security processing from said logical data channel of said first user access line to a logical data channel of said second user access line,

said network transmitting a definition of said selected splitting routine to said first user station in said signaling channel of said first user access line, and to said second user station in the signaling channel of said second user access line,

said first user station transmitting said message in said plurality of packets in said logical data channel of said first user access line in accordance with said selected splitting routine and

said second user station combining information received in said plurality of packets in said logical data channel of said second user access line in accordance with a combining routine that is the inverse of said selected splitting routine.

35. Apparatus for secure communication of messages between different ones of a plurality of user stations interconnected via a switching arrangement wherein said switching arrangement comprises

means responsive to a request in a first signaling channel from a first one of said stations for a secure call to a second one of said stations for establishing first and second communication channels without security processing through said switching arrangement between said first and second stations, said first signaling channel being distinct from said first and second communication channels,

means responsive to said request for selecting one of plurality of message splitting routines,

means for storing data defining, for each of said plurality of stations, security code signals defining to said each station said plurality of splitting routines,

means responsive to said request and said selection, for reading said stored data to determine a first security code signal defining said selected splitting routine to said first station and a second security code signal defining a combining routine associated with said selected splitting routine to said second station,

means for transmitting said first security code signal in said first signaling channel to said first station and

means for transmitting said second security code signal in a second signaling channel to said second station, said second signaling channel being distinct from said first and second communication channels,

wherein said first station comprises means responsive to said first security code signal for splitting a message into first portions and second portions in accordance with said selected splitting routine and means for transmitting said first portions and said second portions over said first and second communication channels, respectively, and

wherein said second station comprises means responsive to said second security code signal and to a receipt of said first and second portions from said first and second communication channels, for reforming said message in accordance with said combining routine associated with said selected splitting routine.