KR20020041813A - Method and apparatus for encrypting transmissions in a communication system - Google Patents

Abstract

By encrypting transport traffic at independent protocol layers L1 220, L2 210 and L3 200, independent cryptographic elements 204 are assigned to independent types of transport traffic 201, 203, 205, and differ according to service conditions. A method and apparatus for enabling the implementation of an encryption level. The cryptographic element 204 uses a so-called crypto-sync in conjunction with a semi-permanent encryption key to prevent replay attacks from rogues from the mobile station. Since the crypto-sync value changes, a method for achieving crypto-sync synchronization at the mobile station and base station is also provided.

Description

METHOD AND APPARATUS FOR ENCRYPTING TRANSMISSIONS IN A COMMUNICATION SYSTEM}

Today's communication systems are required to support a variety of applications. Such communication systems may include CDMA systems or "cdma2000 spread spectrum systems" that comply with the "TIA / EIA / IS-95 Mobile Station-Base Station Compatibility Standard for Dual-Mode Wideband Spread Spectrum Cellular Systems" (hereinafter referred to as IS-95 standard). There is a CDMA system that conforms to the TIA / EIA / IS-2000 standard (hereinafter referred to as IS-2000 standard). Another CDMA standard is the W-CDMA standard, document number 3G TS 25.211 and 3G TS 25.214, embodied in the third generation partnership project "3GPP". CDMA systems enable voice and data communication between users over land links. The use of CDMA technology in a multiple access communication system is described in U.S. Patent No. 4,901,307, Spread Spectrum Multiple Access Communication System Using Satellite or Magnetic Repeater, and U.S. Patent No. 5,103,459, Inventive Name "CDMA Telephone Systems and methods for generating waveforms in a system, the two inventions of which are assigned to the applicant of the present invention and are incorporated herein by reference. Other examples of communication systems are TDMA systems and FDMA systems.

In this specification, a base station refers to hardware that communicates with a remote station. A cell refers to a hardware or geographic coverage area depending on the context in which the term is used. A sector is part of a cell. Because sectors in a CDMA system have cell attributes, the things described by the cells can be extended to sectors.

In a CDMA system, communication between users is through one or more base stations. The first user on the remote station communicates with the second user on the second remote station by sending data to the base station on the reverse link. The base station can receive the data and forward the data to another base station. The data is sent to the second remote station on the forward link of the same base station or a second base station. The forward link refers to the transmission from the base station to the remote station, and the reverse link refers to the transmission from the remote station to the base station. In an IS-95 Is-2000 FDD mode system, independent frequencies are assigned to the forward and reverse links.

In the field of wireless communications, the security of over-the-air transmission is becoming an increasingly important field of communication systems. Security is often maintained through an encryption protocol that prevents exposure of private communications between the parties and / or prevents rogue mobile stations from accessing services that have not been paid to the communication service provider. Encryption is the process by which data is manipulated by a random process, making it invisible to anyone but the intended recipient. Decryption is the process of restoring the original data. One algorithm commonly used in the industry is the Enhanced Cellular Message Encryption Algorithm (ECMEA), which is block encryption. Because of the sophistication of today's code-breakers and "hackers", there is a need to create stronger and more secure encryption processes to protect wireless communication service users and service providers.

TECHNICAL FIELD The present invention generally belongs to the field of wireless communications, and more particularly, relates to a method and apparatus for providing secure transmission in a wireless communication system.

1 is a block diagram of an exemplary CDMA system.

2 is a block diagram of a configuration of an encryption method.

3A, 3B and 3C show samples for a transport frame structure.

4 is a block diagram of a process for converting an unencrypted data unit to an encrypted data unit.

5 is a transmission frame structure for packet data traffic.

6 is a flowchart of an exemplary transmission signal sent from a mobile station to a base station.

7 is a flow diagram for a successful crypto-sync exchange between an LMS and a base station.

8 is a flow chart of an attempted replay attack.

Fig. 9 is a flowchart of exchange of encryption keys in the event of a register error.

10 is a transmission frame for an exemplary communication system.

11 is a flowchart of a transmission signal when the base station detects a decoding error.

Fig. 12 is a flowchart of a transmission signal when the mobile station detects a decoding error.

A novel and improved method and apparatus for encrypting transmissions is provided, wherein the method for encrypting transmission traffic comprises generating a variable value; And inputting the variable value, encryption key, and transmission traffic into an encryption algorithm.

In one aspect, a method is provided for transmitting authentication variable values from a transmitting end to a receiving end, the method comprising: generating a crypto-sync value at the transmitting end; Generating a first authentication signature from the crypto-sync value and the encryption key at the transmitting end; Sending a crypto-sync value and a first authentication signature to the receiving end; Generating a second authentication signature from the crypto-sync value and encryption key at the receiving end; Increasing the crypto-sync value at the receiving end if the first authentication signature and the second authentication signature match; And requesting an encryption key exchange if the first authentication signature and the second authentication signature do not match.

In another aspect, a method is provided for encrypting a cryptographic-sink value of an encryption algorithm at a transmitting end and a receiving end, the method comprising sending an encrypted message to a receiving end; Identifying a current crypto-sync value associated with the encrypted message frame at the receiving end; If the current crypto-sync value is verified, increasing the current crypto-sync value at the transmitting end and the receiving end; And transmitting an error message from the receiving end to the transmitting end if the current crypto-sync value is not confirmed.

In another aspect, a system is provided for encrypting transport traffic, the transport traffic comprising at least two types, the system comprising two encryption elements each associated with at least one of the at least two traffic types. ; And at least one sequence number generator for generating a plurality of sequence numbers, coupled to the at least two cryptographic elements.

Exemplary embodiments to be described below are used in a wireless telephony communication system configured to use a CDMA over air interface. Nevertheless, those skilled in the art will understand that methods and apparatus for encrypted transmission can be used in any of a variety of communication systems using a wide variety of techniques known to those skilled in the art.

Example CDMA System

As shown in FIG. 1, a CDMA wireless telephone system generally includes a number of base stations 12, a base station controller (BSC) 14, and a mobile switching center (MSC) 16. The MSC 16 is configured to interface with a conventional public switched telephone network (PSTN) 18. MSC 16 is also configured to interface with BSC 14. The BSC 14 is connected to the base stations 12 via a backhaul line. The backhaul lines are configured to support any known interface, including for example E1 / T1, ATM, IP, frame relay, HDSL, ADSL or xDSL. It is understood that there are two or more BSCs 14 in the system. Each base station 12 preferably comprises at least one sector (not shown), each sector comprising an omnidirectional antenna or an antenna directed radially from the base stations 12. Optionally, each sector includes two antennas for diversity reception. Each base station 12 is preferably designed to support multiple frequency assignments. The intersection of sector and frequency allocation is called a CDMA channel. Base stations 12 are also referred to as base station transceiver subsystem (BTS) 12. Optionally, “base station” in industry is used to collectively refer to BSC 14 and one or more BTSs 12. The BTS 12 is also called cell site. Mobile station subscriber stations 10 are typically cellular or PCS telephones 10. The system is preferably configured for use in accordance with the IS-95 standard.

During normal operation of a cellular telephone system, base stations 12 receive sets of reverse link signals from sets of mobile stations 10. Mobile stations 10 conduct phone calls or other communications. Each reverse link signal received by a given base station 12 is processed within that base station 12. The resulting data is passed to the BSCs 14. The BSCs 14 provide mobility management functions including adjustment of call resource allocation and soft handoff between the base stations 12. The BSCs 14 also deliver the received data to the MSCs 16, which provide additional routing services for interfacing with the PSTN 18. Similarly, the PSTN 18 interfaces with the MSCs 16, and the MSCs 16 interface with the BSCs 14, which control the base stations 12 to forward link to the sets of mobile stations 10. Send signals Those skilled in the art should understand that in alternative embodiments, the subscriber stations 10 may be fixed stations.

Configuration

2 shows an exemplary configuration for an encryption method that can be used to encrypt voice traffic, data traffic and system services, where the configuration can be implemented at both the transmitting and receiving ends. The structure of the encryption method allows each of the three traffic types listed above to be encrypted for maximum efficiency in separate layers, if desired. As is known, layering is a method for constructing communication protocols in well-defined and encapsulated data units between otherwise disconnected processing entities, ie layers. In the example embodiment shown in FIG. 2, the three protocol layers L1 220, L2 210 and L3 200 allow L1 220 to provide wireless signal transmission and reception between the base station and the mobile station, and L2 ( 210 provides for the correct transmission and reception of signal messages and is used to allow L3 to provide control messages for the communication system.

At layer L3 200, voice traffic 201, packet data traffic 203 and system service 205 are delivered through data units configured in accordance with the standards discussed above. However, encryption is performed for data units carrying system service 205 at this level, but encryption is not performed for packet data traffic 203 or voice traffic 201. In this embodiment, it is implemented by the encrypted lower layers of packet data traffic 203 and voice traffic 201.

ENC_SEQ generator 202 provides the sequence number used to construct the crypto-sync value. In one aspect of the embodiment, the four least significant bits of the sequence number are used to construct the crypto-sync value. The crypto-sync value is a variable that is entered into the encryption algorithm along with the encryption key. The encryption algorithm generates a mask in which unencrypted data is encrypted. The crypto-sync is different from the cryptographic key in that the encryption key is a semi-permanently shared secret, and the crypto-sync value will change for data units sent during the link to defend against replay attacks. In this embodiment, the crypto-sync value will vary due to dependence on the generated sequence number, system time or any other designed identifier. It should be understood that the number of bits used for the crypto-sync value can be changed without changing the scope of this embodiment.

The crypto-sync value is input to the encryption element 204 along with data from the L3 signal element 207 and the teleservice element 205. Remote services include system services such as Short Data Burst Transmission Services, Short Messaging Services, Position Location Services, and the like. In Figure 2, a separate cryptographic element 204 is assigned to process each system service output. The advantage of this architecture is that each service can determine the level of encryption required according to the service requirements. However, alternative embodiments may be implemented in which the encryption element is shared by multiple system services. In this embodiment, the cryptographic elements 204 are multiplexed together at the multiplexer / demultiplexer element 206. In an alternative embodiment, frames of data traffic from packet data element 203 are also encrypted at level L3 200.

At level L2 210, the output from the multiplexer / demultiplexer element is passed through signal LAC 212. At level L1 220, message frames from packet data element 203 pass through radio link protocol (RLP) layer 225, where encryption occurs based on crypto-sync consisting of RLP sequence numbers. do. In this embodiment, the RLP layer 225 is in layer L2 210 and is responsible for retransmission of packet data traffic when a transmission error occurs. Voice traffic frames from voice element 201 are not sequence numbers from ENC_SEQ generator element 202, but independently from encryption element 221 to use the system time as part of the crypto-sync for each voice frame. Encrypted.

The outputs of cryptographic element 221, RLP layer 225 and signal LAC 212 are multiplexed together at MUX and QoS sublayer 227.

There are many advantages of this particular structure. First, each of the L3 signal elements on the remote service and level L3 may specify the level of cryptographic security performed by each of the connected cryptographic elements.

Second, each of the traffic types can properly use system resources to configure crypto-sync for each traffic frame. For example, a voice traffic frame does not have extra space to carry ENC_SEQ. However, since system time is implicitly known to both the transmitting end and the receiving end, system time can be used instead. System time should not be used to encrypt packet data traffic and remote services. If system time is used to configure the crypto-sync, then the data to be encrypted must be encrypted prior to transmission to use the system time in the transmission. Thus, encrypted frames cannot be buffered. If an RLP sequence number or ENC_SEQ number is used, the transmission frames may be temporarily stored in a buffer until encrypted and transmitted. In addition, it is advantageous to use ENC_SEQ rather than message sequence number MSG_SEQ since the LAC layer causes encryption of different unencrypted text with the same encryption mask, which would solve the security of the encryption process.

Third, placing cryptographic elements at a level above the LAC solves the problem of efficiency. If encryption / decryption occurs at the physical layer, the ARQ field will need to be encrypted and decrypted before the ACK is sent. ARQ stands for Automatic Retransmission ReQuest and is a method for checking transmitted data from transmitted ACK to negative ACK. Another problem where encryption / decryption occurs at the physical layer is that the cyclic redundancy check (CRC) bits used to determine transmission errors at the receiver will be calculated based on unencrypted data.

Encryption of Signaling Messages

3A, 3B and 3C are optional structures for composing transport frames in an exemplary embodiment. The transmission frame 300 is composed of the following fields: message length field 301, message type field 302, link access control field 303 inclusively representing various ARQ fields, message identification field 304, message field 305 ), Encoding sequence number field 306, encryption identification field 307, and message CRC field 308. In one embodiment, encryption is performed only on specific fields of the transmission frame. In Figures 3A and 3B, the LAC field 303 is encrypted. However, the LAC field 303 is a problem when the access probe is sent from the mobile station to the base station, but the base station determines that the access probe should be stopped with an ACK. In particular, if the mobile station is unable to decode the LAC field of the message frame from the base station, the mobile station will not stop transmitting the access probe until the maximum number of probes has been sent.

In Figures 3A and D, the message CRC field 308 is encrypted. However, the encryption of the CRC bits makes the validity of the message length field 301 impossible. Thus, Figure 3C is a preferred transmission frame used in the exemplary embodiment.

Generation of encryption mask

Figure 4 shows parameters used to encrypt data in one embodiment, where the data unit includes packet data traffic. The crypto-sync 400 includes an encryption sequence number 401, a service reference identification number 402 identified by sr_id, and a bit value 403 for the transmission direction. sr_id determines the data service corresponding to sr_id. The crypto-sync 400 and encryption key 410 are input to an encryption algorithm 420, such as ECMEA, as mentioned above. It is noted that other encryption methods may be used without affecting the scope of this embodiment. The data unit is passed through an encryption algorithm 420 and encrypted with a cipher text.

In general, a separate crypto-sync value is determined for each data unit to be encrypted. Thus, each crypto-sync value is a different ciphertext, even for the same clear-text.

As indicated above, encryption at the RLP layer is performed through the extended sequence number, sr_id and direction of the channel. These three variables include crypto-sync for use in packet data traffic. In some cases, packet data traffic is encapsulated into frames representing a short data bus (SDB), and the encapsulated frames are carried on a common channel. 5 shows an example of an encapsulated RLP frame in which an ARQ field is encrypted. In frame 500, the payload of data burst message 505 includes three fields: an sr_id field 506, a sequence number field 507, and an encrypted RLP frame 508.

6 is a flow diagram for sample exchange between elements of protocol layers. In mobile station 600, a short burst of data (SDB) is encrypted and sent to base station 650. The RLP element 610 receives data indications and data from the DCR 602. The RLP 610 sends a service data unit (SDU) to the SDBTS element 612 along with the sequence number, data and sr_id, which is part of the remote service of layer L3. SDBTS 612 sends another SDU to cryptographic element 614, including the information from RLP 610 and the EID command. The encryption element 614 sends the message frame information and the encrypted information from the previous element to the L2 / Mux element 616. L2 / Mux element 616 forms a message frame 620 for over-the-air transmission to base station 650. Base station 650 sends an ACK to mobile station 600. At base station 650, the information from the message frame is processed according to the corresponding element that generated the content of the message frame. Accordingly, the L2 / Mux element 622 processes the information added by the L2 / Mux element 616, the encryption element 624 processes the information added by the encryption element 614, and the SDBTS element 626. ) Processes the information added by the SDBTS element 612, the RLP element 628 processes the information added by the RLP element 610, and the data is passed to the DCR 630.

Crypto-Sync Synchronization

In the description of the above embodiment, the security of the encryption process is performed through the use of secure crypto-sync, where the crypto-sync used to encrypt the data is used to encrypt other data units. It is different from the field. Thus, the base station and the mobile station must be able to generate the same crypto-sync to code and decode the same data at the appropriate time. In order to maintain the synchronization of the crypto-sync generated by the mobile station and the base station, some over-the-air transmission must be made. However, over-the-air transmission is open to attacks by log mobile stations (RMS). In the proposed security method, the base station does not accept the crypto-sync value proposed by the mobile station until the mobile station proves to be a legitimate subscriber. Refusal to accept crypto-sync values prevents a "playback attack," where the RMS allows the base station to apply the same encryption mask to two different plaintexts, which solves the security problem of encryption. For example, suppose E is a ciphertext, P is plain text, and M is an encryption mask. If the crypto-sync is the same for plaintext P and plaintext P ', then using modular 2 summation, E = M + P and E' = M + P '. Thus, E + E '= P + P'. Even if the RMS does not know the encryption mask M, the plaintext P and plaintext P 'can be determined. Thus, in one specific example of an attack, the RMS sends a repeated registration message to the base station, which forces the base station to use the same crypto-sync.

In one embodiment, the synchronization of the most significant bits of the crypto-sync is maintained between the legitimate mobile station (LMS) and the base station, while protecting the encryption strength. In one embodiment, the LMS sends an authentication variable, which contains the most significant bit of the crypto-sync and the authentication signature during the registration process. The most significant bit of the crypto-sync is optionally referred to herein as CS_h. One example of the registration of a mobile station entering a wide range of base stations is described in US Pat. No. 5,289,527, entitled "Mobile Communication Device Registration Method," which is incorporated herein by reference.

7 shows a successful exchange of crypto-sync between LMS 700 and base station 710. The LMS 700 sends a registration message 720 to the base station 710, where the registration message includes fields containing CS_h and an authentication signature. In one embodiment, the authentication signature is calculated by using cryptographic-sink CS_h and encryption key Ks in the secure hash function. Hereinafter, the crypto-sync signature or the authentication signature will be referred to as f (CS_h, Ks).

In the above description, the base station 710 is protected from the attack by the RMS mentioned above because the RMS cannot calculate a valid authentication signature for CS_h.

In an alternative embodiment, the security of the communication between the base station and the LMS is protected from the RMS that recorded the registration message from the legitimate LMS. To prevent the base station from using the same CS_h intended for use in the LMS, the base station may be set to increment the least significant bit of the crypto-sync every time a registration message from the mobile station is uploaded to the base station. The least significant bits of the crypto-sync are hereinafter referred to as CS_l. Thus, the crypto-sync value includes CS_h associated with the variable CS_l. In this embodiment, the base station does not repeatedly use the same crypto-sync in the encryption process. If the base station does not have a previous value for CS_l associated with the LMS, the base station may randomly generate CS_l or set CS_l to zero.

8 shows an example of the recorded replay attack. The LMS 700 sends a legitimate registration message 720 to the base station 710. The RMS 730 records the registration message 720 and sends the copied registration message 740 to the base station 710. The base station 710 will not use the same crypto-sync value as for the LMS because the least significant bit of the crypto-sync has been increased.

If the base station cannot generate the same authentication signature sent by the mobile station, the system determines whether the encryption key possessed by the base station is not the same as the encryption key possessed by the mobile station. Then, key exchange must be performed.

Fig. 9 shows the exchange of encryption keys in case of registration error. The LMS 700 sends a registration message 720 to the base station 710 that includes the crypto-sync variable CS_h and the authentication signature f (CS_h, Ks). The base station 710 cannot regenerate the authentication signature f (CS_h, Ks) because the encryption key at the base station 710 is different from the encryption key at the LMS 700. Base station 710 begins key exchange step 770 to ensure that base station 710 and LMS 700 have the same encryption key. The security of key exchange is known to those skilled in the art. However, the identification of crypto-sync is a problem that is not undertaken in the art. As mentioned above, crypto-sync is a variable value that changes for each data unit encrypted in an unencrypted data stream. There must be some verification method to ensure that the crypto-sync value in which the data unit is encrypted is the same as the crypto-sync value used in decryption. This is not a problem where a single key is addressed by the key exchange method where it is exchanged at the beginning of the registration process. Thus, the secure key exchange method is insufficient for the verification requirement of secure crypto-sync exchange.

In one embodiment, new and non-obvious for the cyclic redundancy check (CRC) bit may be implemented to ensure that the crypto-sync generated by both the base station and the mobile station is the same for the same data unit. In this embodiment, an encrypted CRC, also called CRC_enc, is included in the encrypted data unit. The cryptographic CRC is calculated before the unencrypted data unit is added to the encrypted and unencrypted data unit. If a non-encrypted data unit is encrypted with the associated crypto-sync CS_h and encryption key Ks, the encryption CRC is also encrypted with the same crypto-sync CS_h and encryption key Ks. After the encrypted text is generated, a transmission error detection CRC called MSG CRC is added to the encrypted data unit along with the aligned fields necessary for transmission. If the MSG CRC carries a check at the receiving end, CRC_enc is also checked at the receiving end. In case CRC_enc fails to deliver, it is determined whether a CS_h mismatching has occurred. It is noted that when the correct certificate signature f (CS_h, Ks) has been calculated, the validity of the encryption key Ks has already been verified during the registration process.

10 shows a frame structure for message transmission in a system such as cdma2000. Frame 800 consists of various fields needed for the transmission of data traffic from one base station to another. CRC_enc 812 is a CRC calculated on unencrypted protocol data unit L3 PDU 810. The CRC_enc 812 and L3_PDU 810 are then encrypted to form an encrypted field 805. Field CS_L 806 is included to indicate the sequence number for which the crypto-sync was calculated. EID bit 807 is set to 0 or 1 to indicate the presence of an encrypted message. The MSG_CRC field 808 is calculated for the entire message frame 800.

If it is determined that the crypto-sync CS_h is not synchronized with the crypto-sync at the transmitter based on the CRC_enc calculated at the receiver, a recovery procedure is implemented. 11 and 12 are two message flow diagrams illustrating an error recovery procedure. In Fig. 11, the base station detects an error in decryption. In Fig. 12, the mobile station detects an error in decryption.

In FIG. 11, the LMS 900 sends an encrypted message 920 to the base station 910. The CRC bit of the encrypted message 920 is delivered indicating that there is no transmission error and that there is a recoverable amount of transmission error. However, the base station 910 cannot decode the encoders CRC, CRC_enc. The base station 910 sends a "non-decryptable" message 930 to the LMS 900. The LMS 900 then sends a registration message 940 that includes the crypto-sync CS_h, the authentication signature f (CS_h, Ks), and the hook exchange parameters. At this point, LMS 900 and base station 910 both have the same crypto-sync CS_h. The LMS 900 then retransmits the encrypted message 950.

In FIG. 12, the base station 910 sends an encrypted message 920 to the LMS 900. The CRC bit of the encrypted message 920 is delivered indicating that there is no transmission error or that there is a recoverable amount of transmission error. However, the LMS 900 cannot decode the encoders CRC, CRC_enc. The LMS 900 then sends a registration message 940 that includes the crypto-sync CS_h, the authentication signature f (CS_h, Ks), and the hook exchange parameter. At this point, LMS 900 and base station 910 both have the same crypto-sync CS_h. Base station 910 then retransmits encrypted message 950.

Thus, in the two methods described in Figures 11 and 12, message frames that fail to pass the decryption step at the receiving end are retransmitted as if the message frames were sent with an unrecoverable error.

It should be noted from the above example that the CS_h field starts the most significant bits of the crypto-sync for both the forward and reverse links. Even if the forward and reverse links use the same CS_h, since the transmission direction is a variable input to the encryption key generation algorithm, that is, since '0' indicates a forward link message and '1' indicates a reverse link message, Another encryption result is derived. In one embodiment, the crypto-sync value is increased independently after startup.

The choice of crypto-sync values by the mobile station may also be important. To maintain encryption security, crypto-sync should not be repeated during over-the-air transmissions. In one embodiment, the mobile station sets the crypto-sync value to 1 added to the maximum value between the most significant bit of the current forward link crypto-sync value CS_h _{fwd and} the most significant bit of the current reverse link crypto-sync value CS_h _rev . do. Therefore, CS_h = 1 + max (CS_h _fwd , CS_h _rev ).

Accordingly, new and improved methods and apparatus for encrypted transmission have been described. Those skilled in the art will appreciate that the data, instructions, commands, information, signals, bits, symbols, and chips referred to throughout the above description may include voltage, current, electromagnetic waves, magnetic fields or particles, optical fields or particles, or any combination thereof. It will be appreciated that it can be expressed by. Those skilled in the art will appreciate that various illustrative logic blocks, modules, circuits, and algorithm steps described in conjunction with the embodiments disclosed herein may be implemented in electronic hardware, computer software, or a combination thereof. Various graphical components, blocks, modules, circuits, and steps have been described generally in terms of their functionality. Whether the function is implemented in hardware or software depends on the specific application and design limits imposed on the overall system. Those skilled in the art will recognize how to implement hardware and software compatibility and the described functionality for each particular application under these conditions. By way of example, various illustrative logic blocks, modules, circuits, and algorithm steps described in conjunction with the embodiments disclosed herein may be a digital signal processor (DSP), application specific integrated circuit (ASIC), field program designed to perform the described functions. A programmable gate array (FPGA) or other programmable logic element, discrete gate or transistor logic, discrete hardware components such as registers and FIFOs, a processor that performs a series of firmware instructions, any conventional programmable software module and processor, or their It may be implemented or performed in combination. The processor may be a microprocessor, but in the alternative, the processor may be any conventional processor, controller, microcontroller or state machine. The software module may be mounted in RAM memory, flash memory, ROM memory, EPROM memory, EEPROM memory, registers, hard disks, removable disks, CD-ROMs or any known storage medium. The example processor is preferably coupled to a storage medium that reads information and writes the information. Optionally, the storage medium is essential to the processor. The processor and the storage medium may be mounted in an ASIC. The ASIC can be mounted on the phone. Alternatively, the processor may be implemented as two microprocessors with a combination of a DSP and a microprocessor or a DSP core or the like.

The preferred embodiment of the present invention has been described. However, those skilled in the art will understand that various changes can be made to these embodiments without departing from the scope of the present invention. It is intended that the scope of the invention only be limited by the appended claims.

Claims (15)

A method of encrypting transmission traffic, Generating a variable value; And Inputting said variable value, an encryption key and said transport traffic into an encryption algorithm. A method for transmitting an authentication variable from a transmitter to a receiver, Generating crypto-sync at the transmitting end; Generating a first authentication signature from the crypto-sync value and encryption key at the transmitting end; Sending the crypto-sync value and the first authentication signature to the receiving end; Generating a second authentication signature from the crypto-sync value and the encryption key at the receiving end; Increasing the crypto-sync value of the receiving end if the first authentication signature and the second authentication signature match; And Requesting an exchange of encryption keys if the first authentication signature and the second authentication signature do not match. 3. The method of claim 2, wherein generating the crypto-sync value at the transmitting end comprises using a sequence number value, a data unit identification number, and a directional bit. 3. The method of claim 2, wherein generating the crypto-sync value at the transmitting end comprises using a system time value and direction bits. 3. The method of claim 2, wherein generating the first authentication signature comprises using the crypto-sync value and the encryption key in a hash function. 6. The method of claim 5, wherein generating the second authentication signature comprises using the crypto-sync value and the encryption key in the hash function. A method of synchronizing cryptographic-sink values of an encryption algorithm at a transmitting end and a receiving end, Transmitting an encrypted message frame to the receiving end; Identifying a current crypto-sync value associated with the encrypted message frame at the receiving end; Increasing the current crypto-sync value at the transmitting end and the receiving end when the current crypto-sync value is confirmed; And And transmitting an error message from the receiving end to the transmitting end if the current crypto-sync value is not confirmed. 8. The method of claim 7, wherein checking the current crypto-sync value comprises: Decoding a plurality of transmission cyclic redundancy check (CRC) bits to determine a transmission error; And Decoding a plurality of encoded CRC bits that determine if a current crypto-sync value generated by the receiving end matches a crypto-sync value generated by the transmitting end. As a method of generating a message frame, Including a plurality of encoding CRC bits in a data field; Encrypting the data field, wherein cryptographic-sink is used to encrypt the data field; And Adding a plurality of transmit CRC bits to the data field. The method of claim 9, Adding sequence number information to the encrypted data field; And Adding an encryption bit to the encrypted data field, the encryption bit indicating whether the data field is encrypted. A system for encrypting transport traffic, the transport traffic comprising at least two traffic types, the system comprising: At least two cryptographic elements each associated with at least one of the at least two traffic types; And And at least one sequence number generator for generating a plurality of sequence numbers, coupled to the at least two cryptographic elements. An apparatus for encrypting traffic independently according to traffic type in a wireless communication system, Processor; And A storage element coupled to the processor, the instruction set being executable by the processor, wherein the instruction set comprises: Generating a crypto-sync value at the transmitting end; Generating a first authentication signature from the crypto-sync value and encryption key at the transmitting end; Sending the crypto-sync value and the first authentication signature to the receiving end; Generating a second authentication signature from the crypto-sync value and the encryption key at the receiving end; Increasing the crypto-sync value at the receiving end if the first authentication signature and the second authentication signature match; And And a storage element comprising a set of instructions for requesting an encryption key exchange if the first authentication signature and the second authentication signature do not match. An apparatus for encrypting traffic independently according to traffic type in a wireless communication system, Processor; And A storage element coupled to the processor, the instruction set being executable by the processor, wherein the instruction set comprises: Transmitting an encrypted message frame to the receiving end; Identifying a current crypto-sync value associated with the encrypted message frame at the receiving end; Increasing the current crypto-sync value of the transmitting end and the receiving end when the current crypto-sync value is confirmed; And And a storage element comprising instructions for transmitting an error message from the receiving end to the transmitting end if the current crypto-sync value is not confirmed. An apparatus for transmitting authentication variables from a transmitting end to a receiving end, Means for generating a crypto-sync value at the transmitting end; Means for generating a first authentication signature from the crypto-sync value and an encryption key at the transmitting end; Means for sending the crypto-sync value and the first authentication signature to the receiving end; Means for generating a second authentication signature from the crypto-sync and the encryption key at the receiving end; Means for increasing the crypto-sync value at the receiving end if the first authentication signature and the second authentication signature match; And Means for requesting an encryption key exchange if the first authentication signature and the second authentication signature do not match. An apparatus for synchronizing cryptographic-sink values of an encryption algorithm at a transmitting end and a receiving end, Transmitting an encrypted message frame to the receiving end; Means for verifying a current crypto-sync value associated with the encrypted message frame at the receiving end; Means for increasing the current crypto-sync at the transmitting end and the receiving end if the current crypto-sync value is confirmed; And And means for transmitting an error message from the receiving end to the transmitting end if the current crypto-sync value is not confirmed.