WO2000031918A1 - Procede et dispositif de chiffrement en ligne - Google Patents

Procede et dispositif de chiffrement en ligne Download PDF

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Publication number
WO2000031918A1
WO2000031918A1 PCT/US1999/026960 US9926960W WO0031918A1 WO 2000031918 A1 WO2000031918 A1 WO 2000031918A1 US 9926960 W US9926960 W US 9926960W WO 0031918 A1 WO0031918 A1 WO 0031918A1
Authority
WO
WIPO (PCT)
Prior art keywords
unique word
state
cipher
receiving
information coupled
Prior art date
Application number
PCT/US1999/026960
Other languages
English (en)
Inventor
Anthony R. Noerpel
Chandra Joshi
Mohammad Soleimani
Original Assignee
Hughes Electronics Corporation
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Hughes Electronics Corporation filed Critical Hughes Electronics Corporation
Priority to AU17233/00A priority Critical patent/AU1723300A/en
Publication of WO2000031918A1 publication Critical patent/WO2000031918A1/fr

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Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L9/00—Cryptographic mechanisms or cryptographic arrangements for secret or secure communications; Network security protocols
    • H04L9/12—Transmitting and receiving encryption devices synchronised or initially set up in a particular manner
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L2209/00—Additional information or applications relating to cryptographic mechanisms or cryptographic arrangements for secret or secure communication H04L9/00
    • H04L2209/80—Wireless

Definitions

  • the present invention relates in general to synchronizing
  • Wireless communication systems transfer information, such as
  • the information transfer is intended to go from one transmitter to a
  • wireless communications can be a disadvantage. Accordingly, wireless
  • the radio link between the two transceivers must be established in the clear (i.e., not enciphered), because the transceivers have not yet agreed upon a cipher key. Once a cipher key is transferred, the cipher process can begin. However, the start of
  • transceiver must be synchronized with the start of deciphering at the first transceiver. Further, the reverse must occur if a transition back to
  • the communicating transceivers typically agree to transition
  • Multipath fading can also cause
  • a typical cellular communications system employs network
  • transceivers to revert to the original state (e.g., clear mode) and start the
  • PCS personal communications systems
  • the present invention provides an improved
  • the method begins by
  • the transceiver receives a second unique word.
  • transceiver then transitions to a second mode of operation in response
  • the first mode comprises
  • the second mode comprises an enciphered mode.
  • the first mode comprises an enciphered mode and
  • the second mode comprises a clear mode.
  • a method for synchronizing cipher encoding at a transceiver.
  • the method begins by receiving clear information coupled to a first
  • the transceiver receives clear information
  • the transceiver transmits
  • the transceiver then begins receiving enciphered
  • transceiver begins transmitting enciphered information coupled to the
  • the transceiver comprises
  • the transceiver In other preferred embodiments, the transceiver
  • the step of receiving clear information coupled to a second unique word comprises a portable telephone.
  • the step of receiving clear information coupled to a second unique word further 00/31918
  • word further comprises transmitting a cipher response message.
  • the step of transmitting clear information coupled to the second unique word further comprises transmitting a cipher response message.
  • the method comprises the step of receiving clear
  • the method further comprises the step of transmitting clear information coupled to a second unique word.
  • the method comprises the step of receiving
  • the method comprises the step of transmitting enciphered information
  • the method furthermore,
  • the method comprises the step of
  • the method comprises the step of receiving clear
  • the method further comprises the step of transmitting clear information coupled to the first
  • the transceiver comprises
  • unique word further comprises receiving a cipher response message.
  • coupled to the second unique word further comprises transmitting a
  • an apparatus for synchronizing cipher encoding is provided.
  • the system comprises a detector for determining a unique word
  • the system further comprises a
  • system comprises a delay unit for storing a reception cipher state
  • the apparatus further comprises
  • the apparatus further comprises a multiplexer for encoding a message to
  • the apparatus further comprises a decipher
  • FIG. 1 is a block diagram of a satellite system that
  • FIG. 2 is a block diagram of a transceiver, suitable for use
  • FIG. 3 is a state transition diagram illustrating the
  • a cipher synchronizer such as the cipher synchronizer
  • FIG. 2 depicted in FIG. 2; and, FIG. 4 is a flow diagram illustrating a method of cipher
  • transceivers on one of two or more states may employ the techniques
  • FIG. 1 A first transceiver (10a, 10b, or 10c)
  • a signal e.g., a radio signal
  • the first transceiver may be a mobile terminal 10a, such as a portable telephone or portable computer.
  • the first transceiver may be a fixed ground based system 10b or a space based system 10c.
  • the second transceiver 12 is a satellite, and the
  • third transceiver 14 is a gateway to a network.
  • any of the foregoing devices (10a, 10b, 10c, 12, 14) may be replaced with any device capable of transmitting and receiving signals.
  • a computer configured to transmit and receive signals over a network
  • FIG. 2 is a block diagram of a transceiver 10 suitable for use
  • the radio signal contains information (in either clear or enciphered mode) coupled
  • UWA e.g., adjacent in time
  • UWB unique word
  • the state of the UW is also used as an input to a cipher
  • the UW is less susceptible to loss from bursts and multipath fading due to its cross correlation properties. Accordingly, the
  • demodulated signal is processed by the demodulator/synchronization
  • detector 22 to determine the current state of the received UW.
  • detector 22 determines which of two or more unique words (e.g., UWA or UWB) is coupled to the information in the signal by comparing the
  • One of the detector outputs, S1 i.e., the current UW state, UWA or UWB
  • S1 is then sent to the cipher synchronizer 25.
  • the cipher synchronizer 25 uses the current UW state S1
  • next deciphering State S3 determines if the next signal
  • next packet of data received is to be clear (not enciphered) or
  • the output S3 is delayed by a delay unit 28.
  • unit 28 may be implemented in a variety of know manners. For example,
  • the delay unit 28 could be
  • the delay unit is implemented using a semiconductor gate.
  • the delay unit is implemented using a semiconductor gate.
  • the next deciphering state S3 becomes the current deciphering state S2.
  • the current deciphering state S2 is used by the decipher unit 30 as an enable/disable signal. If the current deciphering state S2
  • the decipher/decoder unit 30 deciphers the demodulated data in a known manner before
  • the current deciphering state S2 is also used as an input by
  • the next enciphering state S4 determines if the
  • next data signal transmitted 34 should be enciphered or not.
  • enciphering state S4 is used by an enciphering unit 36 as an
  • enciphering unit 36 does nothing except pass transmit data 34 encoded
  • the enciphering unit 36 enciphers the encoded transmit data in a known
  • the next encoding state S5 determines if the next
  • transmit data 34 is optionally enciphered and then coupled with a UW
  • synchronizer 25 may implement the functionality of the state transition
  • a logic circuit such as a multiplexer or a
  • microprocessor executing software instructions could implement the
  • encipher state S4 will be "clear" (i.e., do not encipher the next
  • decipher state S2 is "decipher"
  • the next decipher state S3 should
  • FIG. 4 A flowchart of a program that can be implemented by a pair of transceivers to synchronize cipher/clear mode in accordance with the teachings of the present invention is illustrated in FIG. 4.
  • control circuit such as
  • one of the transceivers is a mobile terminal 10a and the other is gateway to a network 14. Further, in this example, one of the transceivers is a mobile terminal 10a and the other is gateway to a network 14. Further, in this example, one of the transceivers is a mobile terminal 10a and the other is gateway to a network 14. Further, in this example, one of the transceivers is a mobile terminal 10a and the other is gateway to a network 14. Further, in this
  • the network gateway 14 could initiate the transaction (block
  • the mobile terminal 10a initiates the transaction by
  • the network 14 receives the information (block 52).
  • the network 14 Before the network 14 responds to the reception, it determines if it
  • the network 14 also transmits information in the clear using UWA (block 56). Subsequently, the mobile terminal 10a receives the
  • UWB (block 64). The reception of UWB signals the transition from clear
  • Block 62 includes a "Cipher Start” message to signal the transition from
  • enciphered message using UWB (block 64 to block 66) includes a
  • the network 14 transmits its next message enciphered using UWA (block 68).
  • UWA the network 14 is indicating to the mobile terminal 10a that the transition from clear mode to cipher mode was successful. Subsequently, the mobile terminal 10a receives (block 66).
  • the network 14 receives the information in the
  • a predetermined algorithm or user command may indicate that the system should attempt to communicate in clear mode. If it is not yet time to enter clear mode, the network 14 also
  • the mobile terminal 10a receives the information (block 70) and the
  • the network 14 iterates until the network 14 determines that the system should exit the cipher mode (block 76). At that time, the network 14 transmits one
  • UWB (block 82) .
  • the reception of UWB signals the transition from cipher mode to clear mode, and the transmission of UWB
  • UWB (block 78 to block 80) includes a "Cipher Stop" message to signal
  • Block 84 includes a "Cipher Response” message to acknowledge the
  • the network 1 transmits its next message in the clear using
  • UWA (block 56). By using UWA, the network 14 is indicating to the
  • the mobile terminal 10a transmits (block 1).

Landscapes

  • Engineering & Computer Science (AREA)
  • Computer Security & Cryptography (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Mobile Radio Communication Systems (AREA)

Abstract

La présente invention concerne un procédé et un dispositif de chiffrement en ligne. Un premier émetteur-récepteur envoie un signal à un second émetteur-récepteur, le signal contenant une information (en clair ou chiffrée) et un mot unique (par exemple, UWA ou UWB). Le mot unique et l'état de déchiffrement sont utilisés par un synchroniseur de chiffrement afin de déterminer l'état de déchiffrement suivant, l'état suivant de chiffrement ainsi que l'état suivant de codage. Le synchroniseur de chiffrement effectue cette détermination en suivant quatre règles. La première règle déclare que si l'état de décodage en cours est UWA et que l'état en cours de déchiffrement est « clair », alors l'état suivant de déchiffrement sera « clair », l'état suivant de chiffrement sera « clair », et l'état suivant de codage sera UWA. La deuxième règle déclare que si l'état de décodage en cours est UWB et que l'état de déchiffrement en cours est « clair », alors l'état de déchiffrement suivant serait « déchiffrement », l'état de chiffrement suivant serait « chiffrement », et l'état de codage suivant serait UWB. La troisième règle déclare que si l'état de codage en cours est UWA et que l'état de déchiffrement en cours est « déchiffrement », alors l'état de déchiffrement suivant devrait rester « déchiffrement », l'état de chiffrement suivant devrait rester « chiffrement » et l'état de codage suivant devrait être UWA. La quatrième règle déclare que si l'état de décodage en cours est UWB et que l'état de déchiffrement en cours est « déchiffrement », alors l'état de déchiffrement suivant devrait être « clair », l'état de chiffrement suivant devrait être « clair »', et l'état de codage suivant devrait être UWB.
PCT/US1999/026960 1998-11-25 1999-11-16 Procede et dispositif de chiffrement en ligne WO2000031918A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AU17233/00A AU1723300A (en) 1998-11-25 1999-11-16 Method and apparatus for synchronizing cipher encoding

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US19991698A 1998-11-25 1998-11-25
US09/199,916 1998-11-25

Publications (1)

Publication Number Publication Date
WO2000031918A1 true WO2000031918A1 (fr) 2000-06-02

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ID=22739553

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/US1999/026960 WO2000031918A1 (fr) 1998-11-25 1999-11-16 Procede et dispositif de chiffrement en ligne

Country Status (2)

Country Link
AU (1) AU1723300A (fr)
WO (1) WO2000031918A1 (fr)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1622331A1 (fr) * 2004-07-30 2006-02-01 M-Stack Limited Dispositif et méthode d'application de chiffrement dans un système UMTS
US7333442B2 (en) 2004-07-30 2008-02-19 M-Stack Limited Apparatus and method for applying ciphering in universal mobile telecommunications system

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0411538A2 (fr) * 1989-07-31 1991-02-06 Nec Corporation Système de communication par satellite opérant en mode asynchrone pour transmission d'une station centrale vers une station terminale
US5185796A (en) * 1991-05-30 1993-02-09 Motorola, Inc. Encryption synchronization combined with encryption key identification
US5781595A (en) * 1994-06-29 1998-07-14 Mitsubishi Denki Kabushiki Kaisha Voice transmitting apparatus and voice receiving apparatus using unique word patterns

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0411538A2 (fr) * 1989-07-31 1991-02-06 Nec Corporation Système de communication par satellite opérant en mode asynchrone pour transmission d'une station centrale vers une station terminale
US5185796A (en) * 1991-05-30 1993-02-09 Motorola, Inc. Encryption synchronization combined with encryption key identification
US5781595A (en) * 1994-06-29 1998-07-14 Mitsubishi Denki Kabushiki Kaisha Voice transmitting apparatus and voice receiving apparatus using unique word patterns

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1622331A1 (fr) * 2004-07-30 2006-02-01 M-Stack Limited Dispositif et méthode d'application de chiffrement dans un système UMTS
US7333442B2 (en) 2004-07-30 2008-02-19 M-Stack Limited Apparatus and method for applying ciphering in universal mobile telecommunications system

Also Published As

Publication number Publication date
AU1723300A (en) 2000-06-13

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