CN1756427A

CN1756427A - Switching method between systems

Info

Publication number: CN1756427A
Application number: CN 200410084841
Authority: CN
Inventors: 胡伟华
Original assignee: Huawei Technologies Co Ltd
Current assignee: Huawei Technologies Co Ltd
Priority date: 2004-09-30
Filing date: 2004-09-30
Publication date: 2006-04-05
Anticipated expiration: 2024-09-30
Also published as: CN1294785C

Abstract

The invention discloses a switch method for mobile terminal from WCDMA to GPRS, which comprises: terminal starts route update operation; during encryption negotiation process, if configuring GPRS to encipher, SGSN sends identification and encipher information contained encryption algorithm and encryption key to terminal; if configuring GPRS not to encipher, SGSN sends identification and encipher information contained forcing terminal stopping enciphering operation to terminal; after receiving said information, the terminal returns response information to SGSN; SGSN updates route. This invention can increases stability for system switch.

Description

The method of switching between a kind of system

Technical field

The system that the present invention relates to radio communication is a handoff technique, specially refers to the inter-system switching method of a kind of portable terminal from Wideband Code Division Multiple Access (WCDMA) (WCDMA) system to GPRS (GPRS) system.

Background technology

Because mobile communication system is intrinsic, user data must be exposed in the air interface of wireless access network in the process that transmits, and therefore, aloft the transmission safety of user data is subjected to a certain degree threat on the interface.For the safety of guarantee information, the rights and interests of maintenance customer and operator, common solution are in the air interface of wireless access network user's data to be carried out encrypted transmission, thereby avoid user's data to be monitored and be cracked.

In gprs system, the cryptographic operation of user data and signaling is finished between portable terminal and GPRS serving GPRS support node (SGSN), when starting encryption, SGSN need carry out encrypted negotiation with portable terminal, determine encryption key and cryptographic algorithm, use identical encryption key and cryptographic algorithm with SGSN to guarantee portable terminal.Wherein, the operable cryptographic algorithm of agreement regulation gprs system comprises GPRS cryptographic algorithm (GEA, GPRS Encryption Algorithm) 1, GEA2, GEA3, GEA4, GEA5, GEA6, GEA7, GEA8,8 kinds altogether.

Fig. 1 is the encrypted negotiation flow process of gprs system.As shown in Figure 1, the encrypted negotiation of gprs system may further comprise the steps:

Step 101:SGSN sends authentication and encrypts request (Authentication and CipheringRequest) message to portable terminal, initiate the encrypted negotiation process, carry authentication random parameter (RAND, Random Challenge) cell and cryptographic algorithm (CipheringAlgorithrn) cell in above-mentioned authentication and the encryption request message;

Step 102: portable terminal calculates Authentication Response parameter and encryption key according to the authentication random parameter RAND that receives, and the Authentication Response parameter that calculates is returned to SGSN by authentication and encrypted response message (Authentication and CipheringResponse), finish the legitimacy authentication of portable terminal.

In above-mentioned encrypted negotiation flow process, SGSN sends to portable terminal with cryptographic algorithm and encryption key, can guarantee that the encryption key of portable terminal use is consistent with SGSN with cryptographic algorithm.Through after the above-mentioned encrypted negotiation process, SGSN and portable terminal just can use encryption key and the cryptographic algorithm after the negotiation that user data and signaling are encrypted, thus the assurance user data safe transmission on the interface aloft.

Need to prove, in above-mentioned gprs system encrypted negotiation process, only when portable terminal carries out encrypting for the first time or portable terminal uses key and SGSN are inconsistent, authentication and encryption request message that above-mentioned SGSN sends are just carried authentication parameters R AND immediately, and in other cases, authentication and encryption request message are only carried cryptographic algorithm information.

In the WCDMA system, the cryptographic operation of user data and signaling is realized between portable terminal and radio network controller (RNC).When log-on data is encrypted, need the encrypted negotiation between RNC and the portable terminal, determine encryption key and cryptographic algorithm, use identical encryption key and cryptographic algorithm to guarantee portable terminal with RNC.Wherein, the operable cryptographic algorithm in the WCDMA system of agreement regulation has only one kind of UEA1 at present.The encrypted negotiation process of WCDMA system is initiated by SGSN.

Fig. 2 has shown the encrypted negotiation flow process of WCDMA system.As shown in Figure 2, the encrypted negotiation flow process of WCDMA system may further comprise the steps:

Step 201-step 202:SGSN transmission authentication and encryption request message are initiated the encrypted negotiation process to portable terminal, carry authentication random parameter RAND in above-mentioned authentication and the encryption request message; After portable terminal receives RAND, calculate Authentication Response parameter and encryption key, return the Authentication Response parameter to SGSN, finish the legitimacy authentication of portable terminal by authentication and encrypted response message;

204:SGSN is according to system configuration for step 203-step, send safe mode command (Security ModeCommand) message and give RNC, order RNC is initiated to the encrypted negotiation process of portable terminal, carries cryptographic algorithm and encryption key that the WCDMA system allows use in the above-mentioned safe mode command; RNC transmits Security Mode Command message and gives portable terminal, wherein carries the cryptographic algorithm that the WCDMA system allows use;

Step 205-step 206: portable terminal receives safe mode command, and returns safe mode and finish message to RNC, confirms to accept the cryptographic algorithm of RNC appointment; RNC receives after the affirmation message of portable terminal, finishes acknowledgement messaging SGSN by safe mode, and above-mentioned safe mode is finished to carry in the message with portable terminal and consulted successful cryptographic algorithm.

By above-mentioned encrypted negotiation flow process, SGSN directly sends to portable terminal with encryption key earlier, by Security Mode Command message encryption key and cryptographic algorithm are sent to RNC again, RNC is behind the encryption key and cryptographic algorithm that receive the SGSN configuration, cryptographic algorithm is sent to portable terminal by Security Mode Command message, can guarantee that with this encryption key of portable terminal use is consistent with encryption key and the cryptographic algorithm that RNC uses with cryptographic algorithm.After carrying out above-mentioned encrypted negotiation, RNC and portable terminal just can use encryption key and the cryptographic algorithm after the negotiation that user data is encrypted, and guarantee the user data safe transmission on the interface aloft.

Need to prove, in the negotiations process of above-mentioned WCDMA system encryption, only when portable terminal carries out encrypting for the first time or portable terminal uses key and SGSN are inconsistent, authentication and encryption request message that above-mentioned SGSN sends are just carried authentication random parameter RAND, and in other cases, only carry out the cryptographic algorithm negotiations process of above-mentioned steps 203 to 206.

Because the encrypted negotiation process of above-mentioned gprs system and WCDMA system is independent of each other, and key and cryptographic algorithm that gprs system and WCDMA system use in the ciphering user data process are all inequality, therefore, if portable terminal is not only can be operated in the gprs system but also can be operated in dual-mode terminal in the WCDMA system, then in order to guarantee that business is not interrupted, when portable terminal when the WCDMA system switches to the gsm system, need carry out encrypted negotiation process as shown in Figure 1 again; And when above-mentioned portable terminal switches to the WCDMA system from gprs system, then need to carry out again encrypted negotiation process as shown in Figure 2.

Switching flow the system that will carry out in the time of will describing above-mentioned portable terminal from the WCDMA system to gprs system in detail below.Because the SGSN equipment of WCDMA system and gprs system can close and establish in the system of reality, therefore, the WCDMA system that handoff procedure is divided into same SGSN inside between said system to WCDMA system between handoff procedure between the system of gprs system and SGSN to two kinds of situations of handoff procedure between the system of gprs system.

Fig. 3 has shown that the inner WCDMA of above-mentioned SGSN system is to handoff procedure between the system of gprs system.As shown in Figure 3, this switching may further comprise the steps:

Step 301: portable terminal and wireless access network are determined to carry out the system from the WCDMA system to gprs system and are switched through switch decision between system.

In this step, whether portable terminal and wireless access network are undertaken switching between system by the decision of processes such as handover measurement and switch decision.

Step 302: portable terminal sends the Routing Area Update request message, notice SGSN initiates the Routing Area Update operation, and route district information, the temporary identity that has portable terminal last time and current place in the above-mentioned Routing Area Update request message identifies, the parameters such as type of Routing Area Update.

Step 303-step 304: if between current service RNC (SRNC) and the portable terminal transfer of data is arranged, then SGSN sends the SRNC context request message to SRNC earlier; After SRNC receives request message, stop immediately sending downlink data, and reply SGSN by context response information to portable terminal, comprising the SRNC current cache, successfully do not send to the sequence number of the packet of current mobile terminal as yet; If do not have transfer of data between current SRNC and the portable terminal, then direct execution in step 305.

Step 305: if encrypt or authentication according to operator's configuration gprs system needs, then SGSN starts the encrypted negotiation flow process of gprs system; Otherwise, do not start the encrypted negotiation process of gprs system.

Step 306-step 307:SGSN order SRNC is transmitted to SGSN with its data in buffer; After SRNC receives command messages, data in buffer is forwarded to SGSN.

Step 308-step 309:SGSN notice SRNC discharges SRNC and is connected with Iu between the core net (CN); SRNC discharges Iu and connects, and returns the Iu Release complete and give SGSN.

Step 310-step 311:SGSN sends Routing Area Update and accepts message to portable terminal, and this Routing Area Update request of notice portable terminal is accepted by network; If accept in the message at above-mentioned Routing Area Update, including CN is the interim identify label that portable terminal is redistributed, then portable terminal must be replied Routing Area Update and be finished message to SGSN, expression has received that the Routing Area Update of core net accepts message, and accepts newly assigned temporary identity sign; Otherwise, need not reply above-mentioned Routing Area Update and accept message.

Fig. 4 has shown that the WCDMA system is to handoff procedure between the system of gprs system between the SGSN recited above.As shown in Figure 4, this switching may further comprise the steps:

Step 401: portable terminal and wireless access network are determined to carry out the system from the WCDMA system to gprs system and are switched through switch decision between system.

Step 402: portable terminal sends the new SGSN of Routing Area Update request message to gprs system, notifies new SGSN to initiate the Routing Area Update flow process.

Route district information, the temporary identity that has portable terminal last time and current place in the described Routing Area Update request message identifies, the cells such as type of Routing Area Update.

Step 403: described new SGSN sends the SGSN context request message to the former SGSN of WCDMA system, asks former SGSN to transmit the data message that SRNC is about to send to portable terminal to new SGSN.

Step 404-step 406: after former SGSN receives the SGSN context request message, judge whether current SRNC has the transfer of data to this portable terminal, if transfer of data is arranged, then former SGSN sends the SRNC context request message to SRNC; After SRNC receives request message, stop to be issued to the downlink data of this portable terminal immediately, reply the SRNC context response information and give former SGSN, and in described response message, carry be buffered in SRNC, do not send to the sequence number of the packet of portable terminal as yet; The bag sequence number that former SGSN will be buffered in SRNC, do not send to the packet of portable terminal as yet passes to new SGSN by the SGSN context response information.

If do not have transfer of data between SRNC and the portable terminal, then former SGSN directly returns response message to new SGSN.

Step 407: if encrypt or authentication according to operator's configuration gprs system needs, then new SGSN starts gprs system encrypted negotiation flow process; If gprs system does not need to encrypt or authentication, then do not start gprs system encrypted negotiation flow process.

Step 408: new SGSN sends the SGSN context acknowledgement message to former SGSN, notifies former SGSN to transmit the SRNC data in buffer to new SGSN.

Step 409: after former SGSN received above-mentioned SGSN context acknowledgement message, order SRNC was forwarded to former SGSN with data in buffer.

Step 410:SRNC transmits its data in buffer and is forwarded to former SGSN after receiving and transmitting data command.

Step 411: former SGSN will receive data and continue to be forwarded to new SGSN.

The new SGSN of step 412-step 413:GPRS system sends update packet data protocol (PDP, Packet Data Protocol) context request message is to GGSN (GGSN), and change has taken place the SGSN at the current place of notice GGSN portable terminal; GGSN is updated to the parameter of new SGSN with the PDP Context parameter relevant with SGSN this portable terminal its preservation by former SGSN, for example: the IP address, port numbers and the data transmission quality that the PDP Context parameter modifications such as IP address, port numbers and data transmission quality of the former SGSN of the WCDMA system that preserves are become the new SGSN of gprs system; And return and upgrade PDP content response message to new SGSN.

Step 414-step 421: new SGSN initiates more new technological process of position to attaching position register (HLR); HLR notifies the user contracting data of former SGSN deletion current mobile terminal; Behind the user contracting data of former SGSN deletion current mobile terminal, indication SRNC discharges Iu and connects; Subsequently, HLR inserts mobile subscriber's subscription data to new SGSN; After above-mentioned flow process was finished, HLR notified new SGSN position to upgrade successfully.

Step 422-423: new SGSN issues Routing Area Update and accepts message, and the request of notice portable terminal Routing Area Update is accepted by network; If accepting to comprise in the message core net at Routing Area Update is the temporary identity sign that portable terminal is redistributed, then portable terminal must be replied Routing Area Update and be finished message, expression receives that the Routing Area Update of core net accepts message, and accepts newly assigned temporary identity sign; Otherwise, needn't reply Routing Area Update and accept message.

By switching flow between the system between above-mentioned SGSN inside and the SGSN, the portable terminal that can realize bimodulus switches to gprs system from the WCDMA system, and can be by the encrypted negotiation process of step 305 with step 407, under the situation that gprs system need be encrypted, by the encrypted negotiation flow process between SGSN initiation and the portable terminal, new cryptographic algorithm and encryption key that portable terminal can use SGSN to set according to new encrypted negotiation result, realization guarantees the safe transmission of user data on eating dishes without rice or wine to the cryptographic operation of user data.

At present, in actual applications, most of gprs system is sought the merchant and is not required user data is encrypted, like this, according to switching flow between said system, marquis when the user switches in the gprs system, SGSN just can initiatively not initiate the encrypted negotiation process, does not promptly carry out the encrypted negotiation process in step 305 or step 407.Like this, portable terminal should not have initiatively to initiate under the situation of encrypted negotiation process at SGSN, and logarithm does not reach signaling according to this and encrypts direct transmitting user data and signaling.

But, in the application of reality, because the design manufacturer of a lot of portable terminals is immature to the understanding of agreement, the portable terminal of these manufacturers design is after carrying out between system switching, its cryptographic algorithm and encryption key that place system uses before switching can be preserved, like this, when this portable terminal switches to once more and switches preceding place similar system of system, and when not carrying out new encrypted negotiation, with recovering the cryptographic algorithm and the encryption key of its preservation automatically, user data and signaling are encrypted.For example, if the gprs system at the current place of portable terminal needs to encrypt, after then this portable terminal switches to the WCDMA system from gprs system, its cryptographic algorithm used in gprs system and encryption key can be preserved, so that switch to gprs system once more at this portable terminal, and this gprs system do not carry out under the situation of new encrypted negotiation, recovers cryptographic algorithm and the encryption key preserved automatically, and user data and signaling are encrypted.

So, when if above-mentioned portable terminal switches to a gprs system that does not need user data and signaling are encrypted once more, to cause this gprs system can't discern user data and signaling that portable terminal sends through encrypting, promptly because the SGSN of gprs system and what do not know that portable terminal uses is which kind of cryptographic algorithm and encryption key, and then portable terminal and the encryption key of the SGSN use of gprs system and the situation that cryptographic algorithm is conflicted appear, the result who finally causes will be that user's business is interrupted in the process of above-mentioned switching fully.

Because the current operation gprs system and the operator of WCDMA system have a lot, and the configuration of each operator all is not quite similar, and therefore, above-mentioned situation is very possible generation.

Summary of the invention

In order to solve the problems of the technologies described above, the invention provides a kind of portable terminal switches to gprs system from the WCDMA system method, can guarantee that portable terminal is after switching to gprs system, portable terminal and the encryption key of the SGSN use of gprs system and the situation that cryptographic algorithm is conflicted can not occur, and then the assurance business can not interrupted.

The method of the invention may further comprise the steps:

A, mobile terminal request GPRS serving GPRS support node start the Routing Area Update operation from the WCDMA system to gprs system;

If b configuration gprs system is not encrypted, then the GPRS serving GPRS support node sends the authentication and the encryption request message that include pressure terminating mobile terminal cryptographic operation information and arrives portable terminal;

After portable terminal receives authentication and encryption request message, return authentication and encrypted response message to the GPRS serving GPRS support node;

C, GPRS serving GPRS support node are carried out the Routing Area Update operation from the WCDMA system to gprs system.

The described pressure terminating mobile terminal of this method cryptographic operation message is: algorithm cell value is 0 authentication and encryption request message.

Described authentication of this method and encryption request message do not comprise authentication random parameter cell;

Do not comprise Authentication Response parameter cell in described authentication and the encryption request response.

The described step b of this method further comprises: if the configuration gprs system is encrypted, then the GPRS serving GPRS support node sends the authentication and the encryption request message that comprise cryptographic algorithm and encryption key and arrives portable terminal.

The described GPRS serving GPRS support node of this method is that the GPRS serving GPRS support node of establishing closes in gprs system and WCDMA system.

The GPRS serving GPRS support node of this method gprs system separates with the GPRS serving GPRS support node of WCDMA system;

The GPRS serving GPRS support node that the described GPRS serving GPRS support node of step a to c is a gprs system.

This shows, use WCDMA of the present invention system and can obtain following beneficial effect to the inter-system switching method of gprs system:

1, uses inter-system switching method of the present invention, in the encrypted negotiation process, if the configuration gprs system needs according to operator are encrypted or authentication, then SGSN starts normal encrypted negotiation process, configuration corresponding cryptographic algorithm of portable terminal and encryption key in negotiations process; If according to the configuration gprs system of operator not needs encrypt or authentication, then SGSN also starts normal encrypted negotiation process, force portable terminal user data and signaling not to be encrypted, thereby avoided portable terminal after switching, to recover the cryptographic algorithm of use last time and the service disconnection that encryption key causes, reliability of data transmission in the handoff procedure between the assurance system automatically;

2, use inter-system switching method of the present invention, when having solved the problems referred to above, existing agreement flow process is not carried out bigger modification, therefore, method realizes simple between said system.

Description of drawings

Fig. 1 is the encrypted negotiation flow chart of gprs system;

Fig. 2 is the encrypted negotiation flow chart of WCDMA system;

Fig. 3 is that the inner WCDMA of SGSN system arrives handoff procedure figure between the system of gprs system in the prior art;

Fig. 4 is the handoff procedure figure between the system of gprs system of WCDMA system between the SGSN in the prior art;

Fig. 5 is that the inner WCDMA of SGSN of the present invention system is to the method flow diagram that switches between the system of gprs system;

Fig. 6 for WCDMA system between the SGSN of the present invention to the method flow diagram that switches between the system of gprs system.

Embodiment

For the purpose, technical scheme and the advantage that make invention is clearer, below with reference to the accompanying drawing embodiment that develops simultaneously, the present invention is described in further detail.

Portable terminal of the present invention switches to the method for gprs system from the WCDMA system, and under the situation that gprs system need be encrypted, SGSN normally starts the encrypted negotiation process, finishes the negotiation of key and cryptographic algorithm; And under the situation that does not need to encrypt at gprs system, SGSN also starts normal encrypted negotiation process, force portable terminal in gprs system, not encrypted, with this guarantee encryption key between the SGSN of portable terminal and gprs system and cryptographic algorithm synchronously.

Equally also be divided into below SGSN inner switch and SGSN between switch two kinds of situations, specify the method that WCDMA of the present invention system switches to gprs system.

Fig. 5 has shown that the inner WCDMA of SGSN of the present invention system is to the method flow that switches between the system of gprs system.As shown in Figure 5, method of the present invention specifically may further comprise the steps:

Step 501: portable terminal and wireless access network are through switch decision between system, and after switching the system of decision initiation from the WCDMA system to gprs system, transmission Routing Area Update message starts Routing Area Update to SGSN and operates.

Route district information, the temporary identity that has portable terminal last time and current place in the above-mentioned Routing Area Update flow process message identifies, the parameters such as type of Routing Area Update.

In addition, in this step, portable terminal and wireless access network judge whether to carry out switching between system by processes such as handover measurement and switch decisions, wherein, the method that handover measurement and switch decision are stipulated in can use agreement, the present invention does not limit the employed method of this step.

Step 502-step 503: if between current SRNC and the portable terminal transfer of data is arranged, then SGSN notice SRNC stops to send downlink data to portable terminal, and reports the sequence number of cached data packet; If do not have transfer of data between current SRNC and the portable terminal, direct execution in step 504.

So far, portable terminal is finished the request that starts Routing Area Update.

Step 504-step 505:SGSN starts the encrypted negotiation process of gprs system.

In this step, if according to the configuration of operator, gprs system need be encrypted, and then SGSN starts normal encrypted negotiation process, and in negotiations process configuration corresponding cryptographic algorithm of portable terminal and encryption key.Above-mentioned encrypted negotiation flow process can be referring to encrypted negotiation flow process shown in Figure 1.

If according to the configuration of operator, gprs system does not need to encrypt, and then SGSN also starts normal encrypted negotiation process, forces that portable terminal is set user data and signaling are not encrypted.Its encrypted negotiation flow process also can be referring to encrypted negotiation flow process shown in Figure 1.Stipulate according to agreement, need to carry cryptographic algorithm (Ciphering Algorithm) cell in authentication shown in the step 101 and the encryption request message, portable terminal selects different cryptographic algorithm that user data and signaling are encrypted according to the value of this cryptographic algorithm cell.The agreement regulation, when the value of above-mentioned cryptographic algorithm cell is 0, portable terminal is not encrypted user data, therefore, when operator's configuration gprs system did not need to encrypt, the value of the cryptographic algorithm cell that carries in authentication and the encryption request message was set to 0, just can force portable terminal user data not to be encrypted, thereby avoid portable terminal used cryptographic algorithm and encryption key before recovering automatically after the switching, and then the service disconnection that causes.

And, if operator's GP configuring RS system closing authentication functions does not simultaneously then comprise authentication random number parameters R AND cell at SGSN in authentication that user terminal sends and encryption request message.

Step 506-step 511:SRNC carries out the Routing Area Update operation, and promptly SRNC at first is forwarded to SGSN with its data in buffer; Discharge then with CN between Iu be connected.

Need to prove that except that above-mentioned steps 504-step 505, the signaling process of step 301-step 311 corresponding steps use shown in Figure 3 is identical in the signaling process that step 501-511 uses and the prior art.

Fig. 6 has shown that the WCDMA system is to the method flow that switches between the system of gprs system between the SGSN of the present invention.As shown in Figure 6, described method specifically may further comprise the steps:

Step 601: portable terminal and wireless access network, send Routing Area Update message and operate to the SGSN startup Routing Area Update of new gprs system after determining to switch the system of initiation from the WCDMA system to gprs system through switch decision between system.

In this step, portable terminal and wireless access network judge whether to carry out switching between system by processes such as handover measurement and switch decisions;

Step 602-step 605: if between current SRNC and the portable terminal transfer of data is arranged, then stop to send downlink data, and report the new SGSN of cached data packet bag sequence number to gprs system to portable terminal; If do not have transfer of data between current SRNC and the portable terminal, direct execution in step 603.

The step 606-step 607:GPRS SGSN of system starts the encrypted negotiation process of gprs system.

Need to prove that the operation that this step is carried out is identical with the operation that above-mentioned steps 503 is carried out, and therefore, just has been not described in detail.

Step 608-step 623:SGSN carries out Routing Area Update operation, and promptly SRNC at first is forwarded to new SGSN with the former SGSN of data in buffer by the WCDMA system; Then, GGSN carries out the renewal of this mobile subscriber SGSN sign; SRNC discharge with CN between Iu be connected; At last, the HLR deletion is kept at the user signing contract information among the former SGSN, and user's CAMEL-Subscription-Information is inserted among the gprs system SGSN.

Need to prove that except that above-mentioned steps 606-step 607, the signaling process of step 401-step 423 corresponding steps use shown in Figure 4 is identical in the signaling process that step 601-622 uses and the prior art.

Between system in the above two kinds of cases in the switching flow, by the encrypted negotiation flow process between SGSN and the portable terminal, do not need under the close situation at gprs system, force portable terminal not encrypt association, thereby avoided the portable terminal service disconnection that automatic encryption enabled function causes after switching.

More than lift preferred embodiment; the purpose, technical solutions and advantages of the present invention have been carried out further detailed description; institute is understood that; the above is the preferred embodiments of the present invention; not in order to show the present invention; within the spirit and principles in the present invention all, any modification of being done, be equal to replacement, improvement etc., all should be included within protection scope of the present invention.

Claims

1, a kind of portable terminal switches to the inter-system switching method of gprs system from the WCDMA system, it is characterized in that, said method comprising the steps of:

If b configuration gprs system is not encrypted, then the GPRS serving GPRS support node sends the authentication and the encryption request message that include pressure terminating mobile terminal cryptographic operation information and arrives portable terminal; After portable terminal receives authentication and encryption request message, return authentication and encrypted response message to the GPRS serving GPRS support node;

2, the method for claim 1 is characterized in that, force the authentication and the encryption request message of terminating mobile terminal cryptographic operation information to be described including: algorithm cell value is 0 authentication and encryption request message.

3, method as claimed in claim 2 is characterized in that, described authentication and encryption request message do not comprise authentication random parameter cell;

4, the method for claim 1, it is characterized in that, described step b further comprises: if the configuration gprs system is encrypted, then the GPRS serving GPRS support node sends the authentication and the encryption request message that comprise cryptographic algorithm and encryption key and arrives portable terminal.

5, the method for claim 1 is characterized in that, described GPRS serving GPRS support node is that the GPRS serving GPRS support node of establishing closes in gprs system and WCDMA system.

6, the method for claim 1 is characterized in that, the GPRS serving GPRS support node of gprs system separates with the GPRS serving GPRS support node of WCDMA system;