HK1058277A - Method and apparatus for encrypting transmissions in a communication system - Google Patents

Description

Method and apparatus for encrypting transmissions in a communication system

Background

1. Field of the invention

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

2. Background of the invention

Modern communication systems are required to support a number of diverse applications. One such communication system IS a Code Division Multiple Access (CDMA) system that complies with the TIA/EIA/IS-95 mobile station base station compatibility standard for dual-state wideband transmit spectrum cellular systems, referred to herein as the IS-2000 standard. Another CDMA standard is the W-CDMA standard, under 3 rd generation partnership project "3 GPP", document numbers 3G TS 25.211, 3G TS 25.212, 3G TS25.213, 3G TS 25.214. A CDMA system allows voice and data communications between users over a terrestrial link. The use of CDMA techniques in multiple access communication systems is disclosed in U.S. patent No. 4901307 entitled "transmit spectrum multiple access communication system using satellite or terrestrial repeaters" and U.S. patent No. 5103459 entitled "system and method for generating waveforms in a CDMA cellular telephone system," both assigned to the assignee of the present invention and incorporated herein by reference. Examples of other communication systems are Time Division Multiple Access (TDMA) systems and Frequency Division Multiple Access (FDMA) systems.

In this specification, a base station refers to the hardware with which a remote control station communicates. Cellular refers to the hardware or geographic coverage area, depending on the context in which the term is used. A sector is a partition of a cell. Since the sector of CDMA has the characteristics of a cell, the teachings described in terms of cells are easily extended to sectors.

In a CDMA system, communication between users is through one or more base stations. A first user at one remote station communicates with a second user at a second remote station by transmitting data on the opposite link to the base station. A base station receives data and may send the data to another base station. Data is transmitted on the forward link of the same base station or a second base station to the second remote station. The forward link refers to transmission from the base station to the remote station, and the reverse link refers to transmission from the remote station to the base station. In IS-95 and IS-2000 FDD mode systems, the forward link and reverse link are assigned separate frequencies.

In the field of wireless communications, security of over-the-air transmissions has become an increasingly important area. Maintaining security is typically through cryptographic protocols to prevent the disclosure of private communications by several parties and/or to prevent an unscrupulous mobile station from accessing certain services without paying the communication service provider. Encryption is a process by which data is managed by a random process that is not understood by all but the person to be received. Decryption is simply the process of recovering the original data. One encryption algorithm commonly used in the industry is the "enhanced cellular message encryption algorithm" (ECMEA), which is a block cipher. Due to the complexity of today's decryption and "hacking", there is still a need to produce stronger, more secure encoding processes to protect wireless communication service users and service providers.

Summary of the invention

A novel and improved method and apparatus for encrypting transmissions is presented, wherein the method for encrypting the transmission channel comprises: generating a variable value; the variable value, key and transmission channel are input into an encryption algorithm.

In one aspect, a method for sending an identity confirmation variable from a sender to a receiver is provided, where the method includes: generating a password synchronization value at a sending end; generating a first identity confirmation signature from the cryptosync value and the encryption key at the sending end; sending the encrypted synchronous value and the first identity confirmation signature to a receiving end; generating a second identity verification signature from the cryptosync value and the encryption key at the receiving end; if the first identity confirmation signature is matched with the second identity confirmation signature, a password synchronization value is added at the receiving end; requesting an encryption key change if the first identity confirmation signature and the second identity confirmation signature match.

In another aspect, a method for synchronizing cryptosync values of encryption algorithms at a transmitting end and a receiving end is disclosed, the method comprising: sending the encrypted message frame to a receiving end; verifying, at a receiving end, a current crypto-sync value associated with the encrypted message; if the current password synchronous value is verified, the current password synchronous value is added at the sending end; if the current cryptosync value is not verified, a failure message is sent from the receiving end to the sending end.

In another aspect, a system for encrypting transmission traffic, wherein the transmission traffic includes at least two traffic types, is disclosed, the system comprising: at least two encryption elements, wherein each of the at least two encryption elements is associated with at least one of the at least two traffic types; and at least one sequence number generator to generate a plurality of sequence numbers, wherein the at least one sequence number generator is coupled to the at least two encryption elements.

Brief description of the drawings

The features, objects, and advantages of the invention will be apparent from the detailed description which follows, when read in conjunction with the accompanying drawings.

FIG. 1 is a block diagram of an exemplary embodiment of a CDMA system;

FIG. 2 is a block diagram of an architecture of an encryption scheme;

FIGS. 3A, 3B, 3C and 3D are samples of a transmit frame structure;

FIG. 4 is a block diagram of a process for converting a non-encrypted data unit into an encrypted data unit;

fig. 5 is a transmission frame structure for a packet data service;

FIG. 6 is a flow chart of an exemplary transmitted signal arriving at a base station from a mobile station;

FIG. 7 is a flow chart of a successful cryptosync exchange between the LMS and the base station;

FIG. 8 is a flow chart of an attempt to replay an attack;

FIG. 9 is a flow chart of rekeying after a registration failure;

FIG. 10 is a transmit frame of an exemplary communication system;

FIG. 11 is a flow chart of a transmitted signal in which the base station detects a decryption failure;

fig. 12 is a flow chart of a transmitted signal in which a mobile station detects a decryption failure.

Detailed description of the preferred embodiments

The exemplary embodiments described herein are in a radiotelephone communications system constructed using a CDMA air interface. However, those skilled in the art will appreciate that methods and apparatus for encrypting transmissions exist in a variety of communication systems that use broadband technology.

Exemplary CDMA System

As shown in fig. 1, a CDMA radiotelephone system generally includes a plurality of mobile user devices 10, a plurality of base stations 12, Base Station Controllers (BSCs), and a Mobile Switching Center (MSC) 16. The MSC16 is configured to interface with a conventional Public Switched Telephone Network (PSTN) 18. Fabric MSC16 also interfaces with BSCs 14. The BSCs14 are coupled to the base station 12 via a backhaul. The backhaul may be configured to support any of several known interfaces including E1/T1, ATM, IP, frame Relay, HDSL, ADSL or XDSL. It is believed that there are more than 2 BSCs14 in the system. Each base station 12 preferably includes at least one zone (not shown), each zone including a unidirectional antenna or an antenna pointing in a particular direction radially away from the base station 12. Alternatively, each zone may include two antennas for diversity reception. Each base station 12 may be well designed to support multiple frequency allocations. The intersection of the zones and the frequency allocation may be referred to as a CDMA channel. The base stations 12 may also be referred to as Base Transceiver Subsystems (BTSs) 12. Alternatively, "base station" may be used in the industry to refer to BSC14 and one or more BTSs 12. BTSs12 may also be denoted as "cell sites" 12. Alternatively, individual zones of a given BTS12 may be referred to as cellular sites. The mobile subscriber station 10 is a typical cellular or PCS phone 10. The system IS constructed in accordance with the IS-95 standard.

During typical operation of a cellular telephone system, base station 12 receives sets of reverse link signals from sets of mobile stations 10. The mobile station 10 makes a telephone call or other communication. Each reverse link signal received by a given base station 12 is processed within the base station 12. The resulting data is sent to BSCs 14. The BSCs14 provide call resource allocation and mobility management functions including orchestration of soft handoffs between base stations 12. The BSCs14 also send the received data to the MSC16, which provides other services, interfacing with the PSTN 18. Similarly, PSTN18 interfaces with MSC16 and MSC16 interfaces with BSCs14, which in turn control base stations 12 to transmit sets of forward link signals to sets of mobile stations 10. It will be appreciated by those skilled in the art that the alternative user station 10 may be a fixed station.

Architecture

Fig. 2 shows an exemplary architecture of an encryption scheme that may be used to encrypt voice traffic, data traffic, and system services, where the architecture may be implemented at both the transmitting end and the receiving end. The structure of the encryption scheme allows each of the three traffic types listed above to be well coded, if desired, to achieve maximum efficiency at a separate layer. As known in the art, a sublayer is a way to organize a communication protocol between otherwise decoupled processing entities in an explicit compressed data device. In the exemplary embodiment as shown in fig. 2, three protocol layers L1220, L2210 and L3200 are used, such that L1220 provides transmission and reception of radio signals between the base station and the mobile station, L2210 provides correct transmission and reception of signal messages, and L3 provides control messages of the communication system.

At layer L3200, voice traffic 201, packet data traffic 203 and system services 205 are transmitted via data devices constructed in accordance with the standards discussed above. However, encryption is performed on the data device containing the system service 205, but encryption is not used for the packet data service 203 or the voice service 201. In this embodiment, the encryption of packet data 203 and voice service 201 are implemented by lower layers.

ENC-SEQ generator 202 provides sequence numbers for use in constructing cryptosync values. In one aspect of the embodiment, the crypto-sync value is constructed with the four least significant bits of a sequence number. The cryptosync value is a variable that is input into the encryption algorithm along with the key. The encryption algorithm generates a mask by which unencrypted data is encrypted. Cryptosync differs from an encryption key in that the encryption key is a semi-permanently shared secret, whereas the cryptosync value sent during the link is changed with respect to the data device in order to prevent replay attacks. In such an embodiment, the crypto-sync value may vary depending on the generated serial number or system time or any customized identifier. It should be noted that one may vary the number of bits used as the crypto-sync value without changing the scope of the embodiments.

The crypto-sync value is input to the cryptographic element 204 along with data from the L3 signaling 207 and the remote service element 205. The remote services may include system services such as "short data burst service", "short messaging service", "location service", and the like. In fig. 2, the encryption elements 204 are assigned to process each system service output. The advantage of this structure is that each service can determine the required cryptographic value according to the service requirements. In this embodiment, the outputs of the encryption elements 204 are multiplexed together at a multiplexer/demultiplexer 206. In an alternative embodiment, frames from the data lanes of packet data element 203 are also encrypted at layer L3200.

At the level of L2210, the output of the multiplexer/demultiplexer element passes through a signaling device LAC 212. At the L1220 layer, message frames from the packet data element 203 pass through the Radio Link Protocol (RLP) layer, where encryption is based on encryption synchronization constructed from RLP sequence numbers. In this embodiment, the RLP layer 225 is located at the L2210 layer and is responsible for retransmitting packet data when a transmission error occurs. The frames of the voice communication of the sound component 201 are independently encrypted at the encryption component 221 as part of the encryption synchronization for each voice frame rather than the sequence number from the ENC-SEQ generator component 202 in order to make good use of the system time.

The output of the encryption element 221, the RLP layer 225, and the signaling element LAC 212 are multiplexed together at the MUX and QoS sublayer 227.

The advantages of this particular embodiment configuration are numerous. First, each telecommunications service and L3 signaling at layer L3 may specify an encryption security value to be performed by each individual and connected encryption element.

Second, each traffic type can advantageously utilize system resources to construct encryption synchronization not every frame of traffic. For example, voice traffic frames have no extra space to carry ENC-SEQ. However, the system time may be used as an alternative because the system time varies from frame to frame, and the system time is known by default at the transmitting end and the receiving end. The system time should not be used to encrypt packet data traffic and telecommunications services. If system time is used to construct the encryption synchronization, the data to be encrypted must be encrypted just before transmission in order to use the system time in transmission. Therefore, the encrypted frames cannot be buffered. If RLP sequence numbers or ENC-SEQ numbers are used, the transmission frames may be encrypted and temporarily stored in a buffer until transmission. In addition, it is better to use the ENC-SEQ value instead of the message sequence number MSG-SEQ, because a reset of the LAC layer causes different unencrypted contents with the same encryption mask to be encrypted as well, which would compromise the encryption process.

Third, placing the encryption element at a level above the LAC solves the efficiency problem. If encryption/decryption occurs at the physical layer, the ARQ field needs to be encrypted and decrypted before an ACK can be sent. ARQ is an abbreviation for automatic retransmission request, which is a method for detecting transmitted data through transmitted acknowledgments and negative acknowledgments. Another difficulty that arises if encryption/decryption occurs at the physical layer is that the Cyclic Redundancy Check (CRC) bits used to determine transmission errors at the receiver can be calculated from the unencrypted data.

Encryption of signaling messages

Fig. 3A, 3B, 3C, and 3D are alternative structures for constructing a transmission frame in an exemplary embodiment. The transmission frame 300 is constructed in the following fields: a message length field 301, a message type field 302, a link access control field 303, which generally represents various ARQ fields, a message identification field 304, a message field 305, a coded sequence number field 306, a ciphering identification field 307, and a message CRC field 308. In one embodiment, encryption is applied only to special fields of the transmitted frame. In fig. 3A and 3B, the LAC field 303 is encrypted. However, when the access probe is sent from the mobile station to the base station, the encryption of the LAC field 303 is problematic, but the base station determines that the access probe should stop upon encountering an ACK. In particular, if the mobile station is unable to decode the LAC field of a message frame from the base station, the mobile station does not stop transmitting access probes until the maximum number of probes is transmitted.

In fig. 3A and 3D, the message CRC field 308 is encrypted. However, the encryption of the CRC bits makes the validation of the message length field 301 impossible. Thus, fig. 3C is a preferred transmit frame in the exemplary embodiment.

Generation of an encryption mask

Fig. 4 shows parameters used to encrypt data in an exemplary embodiment, where the data device carries packet data traffic. The cryptosync 400 includes an encryption sequence number 401, a service reference identifier 402, other known values such as sr _ id and a bit value 403 for the transmit direction. One sr _ id determines the data service to which the sr _ id corresponds. The encryption synchronization 400 and encryption key 410 are input to an encryption algorithm 420, e.g., ECMEA as described above. It should be noted that other encryption schemes do not affect the scope of the embodiments and may be implemented in this embodiment. The data device is encrypted into ciphertext by the encryption algorithm 420.

Generally, an individual crypto-sync value is determined for each data device to be encrypted, and thus each crypto-sync value may produce a different ciphertext even for the same text.

As mentioned above, encryption at the RLP layer is achieved by using extended sequence numbers, i.e. an sr _ id and the direction of the channel. These three variables include the crypto-sync value used for packet data traffic. In some cases, packet data services may be packetized in frames that indicate Short Data Bursts (SDB), where the packetized frames are sent on a common channel. Fig. 5 shows an example of a packetized RLP frame in which the 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.

Fig. 6 is a flow diagram of an exemplary handoff between elements in a protocol layer. At mobile station 600, Short Data Bursts (SDB) are encoded and transmitted to a base station 650. The RLP element 610 receives the data indication and data from the DCR 602. The RLP610 sends a Service Data Unit (SDU) data with sequence numbers and sr _ id to the SDBTS element 612, which is part of the telecommunication service in layer L3. The SDBTS element 612 sends another SDU, including information and EID commands from the RLP610, to the ciphering element 614. The encryption element 614 sends the message frame information and encrypted message from the previous element to the L2/Mux element 616. L2/Mux element 616 forms message frame 620 for transmission over the air to base station 650. The base station 650 sends a received message notification 621 to the base station 600. At the base station 650, the information from the message frame is processed according to the corresponding element that generated the content of the message frame. Thus, the L2/Mux element 622 processes messages joined by the L2/Mux element 616, the encryption element 624 processes messages joined by the encryption element 614, the SDBTS element 626 processes messages joined by the SDBTS element 612, and the RLP element 628 processes messages joined by the RLP element 610, with data brought into the DCR 630.

Synchronization of encrypted synchronisation values

In the description of the above embodiments, the security of the encryption process is achieved by using a secure encryption synchronisation value, wherein the encryption synchronisation value used to encrypt a unit of data is different from the encryption synchronisation value used to encrypt other units of data. Therefore, the base station and the mobile station must be able to generate the same crypto-sync value to encode and decode the same data at the appropriate time. Some over-the-air transmission is necessary in order to maintain the synchronicity of the crypto-sync values generated by the mobile station and the base station. However, over-the-air transmissions are open to attack by unscrupulous mobile stations (RMS). In the proposed security scheme, the base station refuses to accept the mobile station's proposed crypto-sync value until the mobile station is certified as a legitimate user. Denial of acceptance of the crypto-sync value prevents "replay attacks" in which the RMS forces the base station to add the same crypto-mask to two different plain texts, which includes security for encryption. For example, assume E is ciphertext, P is plaintext, and M is an encryption mask. If the encryption synchronization values are the same for the plaintext P and the plaintext P ', modulo-2 addition is used, E ═ M + P'. Thus, E + E ═ P + P'. Plaintext P and plaintext P' can be determined even if the RMS does not know the encryption mask M. Therefore, in the specific example of an attack, the RMS may send repeated registration messages to the base station, forcing the base station to use the same crypto-sync value.

In one embodiment, the highest order bits of Legitimate Mobile Station (LMS) and base station cryptosyncs are kept in sync while preserving the strength of the encryption. In an exemplary embodiment, the LMS sends identification variables including the most significant bits of the cryptosync and the identification signature during registration. Hereinafter the most significant bit of the cryptosync is referred to as CS _ h. An example of a process for a mobile station to log into range of a base station is disclosed in U.S. patent No. 5,289,527 entitled "mobile communication device log in method", which is incorporated herein by reference.

Figure 7 shows a successful handover of the cryptosync between the LMS700 and the base station 710. The LMS700 sends a registration message 720 to the base station 710, where the registration message includes a field with CS _ h and an identity confirmation signature. In an embodiment, the identity confirmation signature is calculated by using the cryptosync CS _ h and the encryption key (ks) in a secure hash function. Hereinafter, the cryptosync signature or identity confirmation signature is referred to as f (CS _ h, Ks).

In the above description, the base station 710 is protected from the above attack by the RMS, since the RMS cannot compute a valid identity confirmation signature for CS _ h.

In an alternative embodiment, the security of the communication between the base station and the LMS is protected by the RMS having recorded registration messages from the legitimate LMS. To prevent the RMS from forcing the base station to use the same CS _ h intended for use by the LMS, the base station may set the lowest bit of the cryptosync to be incremented by 1 each time a registration message from the mobile station is loaded to the base station. The lowest bit of the crypto-sync value is hereinafter referred to as CS 1. Thus, the crypto-sync value includes CS _ h concatenated with variable CS 1. In this embodiment, the base station is prevented from reusing the same crypto-sync value in the ciphering process. When the base station has no previous value of LMS related CS1, the base station may randomly generate CS1 or set CS1 to zero.

Fig. 8 shows an example of a replay attack under recording. The LMS700 sends a legitimate registration message 720 to the base station 710. RMS730 logs registration message 720 and sends duplicate registration message 740 to base station 710. The base station 710 will not use the same cryptosync value as the LMS because the least significant number of cryptosyncs has been incremented by 1.

If the base station is unable to generate the same identity confirmation signature as the mobile station sends, the system determines that the key held by the base station is different from the key held by the mobile station and then a key change must be made.

Fig. 9 shows the replacement of keys after a login failure. The LMS700 sends a registration message 720 including the encrypted synchronization variable CS _ h and the identity confirmation signature f (CS _ h, Ks) to the base station 710. The base station 710 cannot replicate the identity confirmation signature f (CS _ h, Ks) because the encryption key of the base station 710 is different from that of the LMS 700. The base station 710 initiates a rekey step 770 so that the base station 710 and the LMS700 have the same encryption key. The security of the rekeying is a known technique to those skilled in the art. However, the verification of the cryptosync value is a problem not mentioned in the art. As previously mentioned, the encryption synchronisation value is a variable value that is different for each data unit encrypted in the unencrypted data stream. There must be some way of checking to ensure that the crypto-sync value used for encryption of the data unit is the same as the crypto-sync value used at the decryption side. This is not a problem posed by the rekeying approach, where individual keys are replaced at the start of the registration process. Therefore, the method of secure rekeying is not sufficient for the verification needs of a secure crypto-sync exchange.

In one embodiment, a novel and non-obvious use of Cyclic Redundancy Code (CRC) bits can be implemented to verify that the crypto-sync values generated by the base station and the mobile station for the same data unit are equal. In this embodiment, an encrypted CRC, also referred to as CRC enc, is included in the encrypted data device. The encrypted CRC is calculated before the unencrypted data device is encrypted and then appended to the unencrypted data device. When an unencrypted data device is encrypted with the associated encryption synchronisation value CS _ h and encryption key Ks, the encrypted CRC is also encrypted with the same encryption synchronisation value CS _ h and encryption key Ks. After the encrypted text is generated, a transmission error detection CRC, called MSGCRC, is appended to the encrypted data device along with various fields necessary for transmission. If MSGCRC passes a detection at the receiving end, CRC _ enc is also detected at the receiving end. If CRC _ enc fails, it is determined that a mismatch of CS _ h occurs. It should be noted that when the correct identity confirmation signature f (CS _ h, Ks) is calculated, the validity of the encryption key Ks has been confirmed during the registration process.

Fig. 10 shows a frame structure of message transmission in a system such as CDMA 2000. Frame 800 is comprised of various fields required to transmit data traffic from one station to another. CRC enc812 is the CRC calculated on the unencrypted protocol data device L3PDU 810. CRC _ enc812 and L3PDU 810 are then encrypted to form encrypted field 805. A field CSL 806 is also included to indicate the sequence number on which the crypto-sync value is calculated. EID bit 807 is also set to zero or a value indicating the presence of an encrypted message. The MSGCRC field 808 is then calculated over the entire message frame 800.

If it is determined that the cryptosync CS _ h is not synchronized with the cryptosync value at the transmitting end according to the CRC _ enc calculated at the receiving end, a recovery procedure must be implemented. Fig. 11 and 12 are two message flow diagrams illustrating the error recovery process. In fig. 11, the base station detects a decryption failure. In fig. 12, the mobile station detects a decryption failure.

In fig. 11, LMS900 sends an encrypted message 920 to base station 910. The CRC bits of encrypted message 920 pass indicating no transmission errors or transmission errors can be recovered. However, the base station 910 cannot decode the value of the encoder CRC, CRC enc. The base station 910 sends a "cannot decrypt" message 930 to the LMS 900. LMS900 then sends a registration message 940 that includes the cryptosync CS _ h, the identity confirmation signature f (CS _ h, Ks), and the hook change parameter. At this point, both the LMS900 and the base station 910 have the same cryptosync CS _ h. LMS900 then resends encrypted message 950.

In fig. 12, the base station 910 sends an encrypted message to the LMS 900. The CRC bits of encrypted message 920 pass indicating that no transmission errors are present or that transmission errors can be recovered. However, the LMS900 cannot decode the value of the encoder CRC, CRC enc. LMS900 then sends a registration message 940 that includes the cryptosync CS _ h, the identity confirmation signature f (CS _ h, Ks), and the hook change parameter. At this point, both the LMS900 and the base station 910 have the same crypto-sync value, CS _ h. Base station 910 then retransmits encrypted message 950.

Thus, in both methods shown in fig. 11 and 12, a message frame that has not passed the decryption step at the receiving end will be retransmitted as if the message frame was transmitted with an unrecoverable error.

It should be noted from the above example that the CS _ h field is initialized for the most significant bits of the forward and reverse link cryptosync. Although the forward and reverse links use the same CS _ h, since the transmission direction is a variable input to the encryption key generation algorithm, different encryption results are produced, i.e., 0 may represent a forward link message and 1 a reverse link message. In one embodiment, the cryptosync value may be independently incremented after initialization.

The choice of crypto-sync value made by the mobile station is also important. To maintain security of encryption, the encryption is sent over the airThe encryption synchronization should not be repeated during transmission. In one embodiment, the mobile station sets the crypto-sync value equal to one (1), adding to the most significant bit CS _ h of the current forward link crypto-sync value_{Forward direction}Highest bit CS _ h of encryption synchronization value with current reverse link_{Reverse direction}The maximum value therebetween. Thus, CS _ h is 1+ max (CS _ h)_{Forward direction}，CS_h_{Reverse direction})。

Thus, a novel and improved method and apparatus for encrypting transmissions has been described. Those of skill in the art will appreciate that the data, instructions, commands, information, signals, bits, symbols, and chips that may be referenced throughout the above description are advantageously represented by voltages, currents, electromagnetic waves, electromagnetic fields or particles, optical fields or particles, or any combination thereof. Those of skill would appreciate that the various illustrative logical blocks, modules, circuits, and algorithm steps described in connection with the embodiments disclosed herein may be implemented as electronic hardware, computer software, or combinations of both. The various illustrative components, blocks, modules, circuits, and steps have been described above generally in terms of their functionality. Whether functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the overall system. Skilled artisans will recognize the interchangeability of hardware and software under these circumstances, and how best to implement the described functionality for each particular application. For example, the various illustrative logical blocks, modules, circuits, and algorithm steps described in connection with the embodiments disclosed herein may be implemented or performed with a Digital Signal Processor (DSP), an Application Specific Integrated Circuit (ASIC), a Field Programmable Gate Array (FPGA) or other programmable logic device, discrete gate or transistor logic, discrete hardware components such as registers and FIFO, a processor executing a set of operating system instructions, any conventional programmable software module and a processor, or any combination thereof designed to perform the functions described herein. The processor is preferably a microprocessor, but in the alternative, the processor may be any conventional processor, controller, microcontroller, or solid state machine. A software module may exist as RAM memory, flash memory, ROM memory, EPROM memory, EEPROM memory, registers, hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art. An exemplary processor is preferably coupled to the storage medium such that information may be read from, and written to, the storage medium. In the alternative, the storage medium may be integral to the processor. The processor and the storage medium may reside in a telephone. A processor may be implemented as a combination of a DSP and a microprocessor, or two microprocessors in conjunction with a DSP core, etc.

Thus, the preferred embodiment of the invention has been shown and described. However, one of ordinary skill in the art will appreciate that numerous changes to the embodiments disclosed herein can be made without departing from the spirit or scope of the present invention. The invention is therefore not limited except as by the following claims.

Claims (15)

1. A method of encrypting traffic for transmission, the method comprising;

generating a variable value; and

inputting variable value, encrypting key, sending service to enter into encryption algorithm.

2. A method for transmitting an identity confirmation variable from a transmitting end to a receiving end, the method comprising:

generating an encryption synchronization value at a sending end;

generating a first identity confirmation signature from the encryption synchronization value and the encryption key at the sending end;

sending the encrypted synchronous value and the first identity confirmation signature to a receiving end;

generating a second identity verification signature from the encrypted synchronisation value and the encryption key at the receiving end;

if the first identity confirmation signature is matched with the second identity confirmation signature, adding an encryption synchronization value at the receiving end; and

requesting a change of the encryption key if the first identity verification signature and the second identity verification signature do not match.

3. The method of claim 2, wherein the step of generating the cryptosynch at the transmitting end includes using a sequence number value, a data unit identification number and a direction bit.

4. The method of claim 2, wherein the step of generating the crypto-sync value at the transmitting end includes using a system time value and a direction bit.

5. The method of claim 2, wherein the step of generating the first identity verification signature comprises using the cryptosynch and the encryption key in a hash function.

6. The method of claim 5, wherein the step of generating a second identity verification signature comprises using the cryptosynch and the encryption key in a hash function.

7. A method for synchronizing crypto-sync values of a crypto algorithm at a transmitting end and a receiving end, the method comprising:

sending the encrypted message frame to a receiving end;

confirming a current encryption synchronization value related to the encrypted message frame at a receiving end;

if the current encryption synchronization value is confirmed, the current encryption synchronization value is increased at the sending end and the receiving end;

if the current encryption synchronization value is not confirmed, a failure message is sent from the receiving end to the receiving end.

8. The method of claim 7, wherein the step of validating the current cryptosynch comprises:

decoding a plurality of transmit Cyclic Redundancy Code (CRC) bits, wherein the transmit CRC bits are used to determine a transmission error;

decoding a plurality of encoded CRC bits, wherein the encoded CRC bits are used to determine whether a current crypto-sync value generated by the receiving end matches a crypto-sync value generated by the transmitting end.

9. A method of generating a message frame, the method comprising:

including a plurality of encoded CRC bits in the data field;

encrypting the data field, wherein the data field is encrypted by adopting an encryption synchronous value; and

multiple transmit CRC bits are appended to the data field.

10. The method of claim 9, further comprising:

appending sequence number information to the encrypted data field; and

an encryption bit is appended to the encrypted data field, wherein the encryption bit indicates whether the data field is encrypted.

11. A system for encrypting transmission traffic, wherein the transmission traffic comprises at least two traffic types, the system comprising:

at least two encryption elements, wherein each of the at least two encryption elements has a relationship with at least one of the at least two traffic types; and

at least one serial number generator for generating a plurality of serial numbers, wherein the at least one serial number generator is coupled to the at least two cryptographic elements.

12. An apparatus for independently encrypting traffic in a wireless communication system according to traffic type, comprising:

a processor;

a storage device coupled to the processor containing a set of instructions for execution by the processor, wherein the set of instructions includes the following instructions:

generating an encryption synchronization value at a sending end;

generating a first identity confirmation signature from the encryption synchronization value and the encryption key at the sending end;

sending the encrypted synchronous value and the first identity confirmation signature to a receiving end;

generating a second identity verification signature from the encrypted synchronisation value and the encryption key at the receiving end;

if the first identity confirmation signature is matched with the second identity confirmation signature, adding an encryption synchronization value at the receiving end; and

requesting a change of the encryption key if the first identity verification signature and the second identity verification signature do not match.

13. An apparatus for independently encrypting traffic in a wireless communication system according to traffic type, comprising:

a processor;

a storage device coupled to the processor containing a set of instructions for execution by the processor, wherein the set of instructions includes the following instructions:

sending the encrypted message frame to a receiving end;

confirming a current encryption synchronization value related to the encrypted message frame at a receiving end;

if the current encryption synchronization value is confirmed, adding the current encryption synchronization value at the sending end and the receiving end;

if the current encryption synchronization value is not confirmed, a failure message is sent from the receiving end to the receiving end.

14. An apparatus for transmitting an identity confirmation variable from a sender to a receiver, comprising:

a device for generating an encrypted synchronization value at a transmitting end;

means for generating a first identity verification signature at the sending end from the encrypted synchronisation value and the encryption key;

means for sending the encrypted synchronisation value and the first identity verification signature to the receiving end;

means for generating a second identity verification signature at the receiving end from the encrypted synchronisation value and the encryption key;

means for incrementing the crypto-sync value at the receiving end if the first identity verification signature matches the second identity verification signature; and

means for requesting a change of encryption key if the first identity verification signature and the second identity verification signature do not match.

15. An apparatus for synchronizing crypto-sync values of a crypto algorithm at a transmitting end and a receiving end, the apparatus comprising:

means for transmitting the encrypted message frame to a receiving end;

means for determining at the receiving end a current encryption synchronisation value associated with the encrypted message frame;

means for increasing the current encryption synchronization value at the transmitting end and the receiving end if the current encryption synchronization value is confirmed;

if the current crypto-sync value is not confirmed, a failure message is transmitted from the receiving end to the device of the receiving end.