CN101267670A - An initialization setup method for secret key survival counter between different access systems - Google Patents

Abstract

Provided is an initialization setting method of a key subsistence counter used between different access systems, in which a user equipment is moved from an evolutional land wireless access network to a land wireless access network, when re-selection is required, following steps are performed: the user equipment determines that a UMTS network is selected during cell re-selection, a high bit virtual value of a counter COUNT-NAS is at least added one to be used as an initial value of a counter START, then, a cell re-selection request is sent to a target service UMTS network; wherein, the counter START is a subsistence counter of an integrality key IK and an encryption key CK of the land wireless access network, the counter COUNT-NAS is a counter recording a non-access layer integrality protection key KNAS-int of the evolutional land wireless access network and the signaling number of a network access server protected by an encryption protection key KNAC-enc. The invention is capable of avoiding a safety loophole that the key subsistence period is prolonged when the UE initiates the cell re-selection between UTRAN and EURAN.

Description

The initial setting method that is used for cryptographic key existence counter among different access systems

Technical field

The present invention relates to moving communicating field, relate in particular to a kind of method that the cryptographic key existence counter among different access systems initialization is provided with that is used for.

Background technology

3GPP (3rd Generation Partnership Project, third generation partner program) grouping system of evolution (Evolved Packet System, be called for short EPS) by land radio access web (the Evolved UMTS Terrestrial Radio Access Network of evolution, be called for short EUTRAN) and EPS core net (Evolved Packet Core is called for short EPC) composition.

Wherein, EPC comprises mobile management unit (MME, Mobility Management Entity), and mobile management unit is responsible for the processing of ambulant management, Non-Access Stratum signaling and the chain of command related works such as management of user security model.Wherein, MME preserves the root key K of EUTRAN _ASME(KeyAccess Security Management Entity, the secret key of access security management entity), and by K _ASMEThe Non-Access Stratum integrity protection key K that generates _NAS-int(Key Non Access Stratum integrity) and Confidentiality protection key K _NAS-enc(Key Non Access Stratum encryption).Also in store these three keys of while UE (User Equipment, subscriber equipment).Also there is a counter COUNT among UE and the MME _-NAS, responsible record has been subjected to key K _NAS-intAnd K _NAS-encNAS (Network Access Server, network access server) the signaling quantity of protection.COUNT _-NASValue two effects are arranged, one is the input parameter that is used for doing NAS layer integrity protection and Confidentiality protection, another one is to be used for strict restriction key K _ASMELife span, work as COUNT _-NASValue arrive family of power and influence's value that operator sets, UE and network side will trigger new Authentication and Key Agreement mechanism (AKA, Authentication and key agreement) and produce new K _ASME, all EPS counters are changed to 0 simultaneously.When connecting, UE and MME use START _-NASValue come recording counter COUNT _-NASHigh Bit Significance.UE uses START _-NASCome count initialized device COUNT _-NAS, be about to START _-NASValue as COUNT _-NASThe value of high-order effective bit (MSB:Most Significance Bit, its concrete figure place is by standard definition) be high Bit Significance, disconnect when connecting, UE uses COUNT _-NASThe value of high-order effective bit upgrade START _-NASValue.

3GPP UMTS (Universal Mobile Telecommunications System, universal mobile telecommunications system) equipment of the management of responsible contextual management of mobility and/or user security model is SGSN (Serving GPRS Support Node, Serving GPRS Support Node) in the system.SGSN also is responsible for authentication UE, and generates key IK (Integrity Key, Integrity Key), CK (CipheringKey, encryption key).The connecting system of 3GPP UMTS system is UTRAN (UMTS TerrestrialRadio Access Network, a wireless access network).

UE also generates IK, CK simultaneously.In the PS territory; UE usage counter START record is subjected to the signaling quantity of key IK and CK protection; when the value of START arrives the family of power and influence who sets and is worth; make new AKA with triggering UE and SGSN, produce new IK, CK; the START value is put O simultaneously; therefore at UMTS, counter START is the existence counter of key IK and CK, and its strictness has limited the life span of key.When connecting, UE and RNC (radio network controller, RadioNetwork Controller) or SGSN use the value of START to be used for the value of high-order effective bit of count initialized device COUNT-I and COUNT-C, when disconnecting connection, UE uses the value of the high-order effective bit of COUNT-I and COUNT-C to upgrade the value of START.Wherein counter COUNT-I is the counter of network access server signaling quantity that writes down the Integrity Key IK protection of the land radio access web that is subjected to evolution, and COUNT-C is the counter of network access server signaling quantity that writes down the encryption key IK protection of the land radio access web that is subjected to evolution.

When UE moved to EUTRAN from UTRAN, UE and MME used IK and CK to produce K _-ASME, use COUNT simultaneously _-NASBe K _-ASMEExistence counter, IK and CK are called K _-ASMEFather's key, K _-ASMEThen be called CK, the sub-key of IK.When UE when EUTRAN transfers to UTRAN, UE and SGSN/RNC use K _-ASMEProduce key IK and CK, use START to limit CK simultaneously, the life span of IK, K _-ASMEThe father's key that is called IK and CK, IK and CK are K _-ASMESub-key.

Owing to when UE carries out sub-district gravity treatment (TAU, Tracking AreaUpdate) between UTRAN and EUTRAN, do not have mandatory requirement to reuse AKA and carry out key updating, the sub-key that is produced by father's key may continue to use a period of time.

In the prior art, between UTRAN and EUTRAN during the gravity treatment of sub-district, the UE counter is not continued mutually and add up, but directly the counter initial value is set to 0, so that behind the TAU, the life span that does not comprise his father's key the life cycle of key, the security breaches that cause cipher key lifetimes to be extended.

Summary of the invention

The invention provides a kind of initial setting method that is used for cryptographic key existence counter among different access systems, when initiating the sub-district gravity treatment to avoid UE between UTRAN and EUTRAN, to move, the security breaches that cipher key lifetimes is extended.

In order to solve the problems of the technologies described above, the present invention also provides a kind of initial setting method that is used for cryptographic key existence counter among different access systems, it is characterized in that, subscriber equipment from the land radio access web of evolution landwards wireless access network move, in the time of need carrying out the sub-district gravity treatment, carry out following steps:

When the UMTS network is arrived in described subscriber equipment decision sub-district gravity treatment, with counter COUNT _-NASHigh Bit Significance add 1 initial value at least as counter START, then, send cell re-selection request to destination service UMTS network;

Wherein, counter START is the Integrity Key IK of land radio access web and the existence counter of encryption key CK, counter COUNT _-NASIt is the Non-Access Stratum integrity protection key K that writes down the land radio access web that is subjected to evolution _NAS-intWith the Confidentiality protection key K _NAS-encThe counter of the network access server signaling quantity of protection.

Further, said method also can have following characteristics:

Described subscriber equipment is earlier with counter COUNT _-NASHigh Bit Significance add 1 at least after, compose to give counter START _-NAS, the value initialization with counter START is counter START then _-NASValue; Counter START wherein _-NASBe to be used for recording counter COUNT _-NASThe counter of high Bit Significance.

Further, said method also can have following characteristics:

Described subscriber equipment is earlier with counter COUNT _-NASHigh Bit Significance add 2 after, compose to give counter START _-NAS, i.e. START=START _-NAS=MSB (COUNT _-NAS)+2; Value initialization with counter START is counter START then _NASValue, counter START wherein _-NASBe to be used for recording counter COUNT _-NASThe counter of high Bit Significance.

Further, said method also can have following characteristics:

After described destination service UMTS network receives that described subscriber equipment sends cell re-selection request, send context request to the source mobile management unit; After described source mobile management unit is received, send context response to described destination service UMTS network; Described destination service UMTS network sends the sub-district gravity treatment to described subscriber equipment again to be confirmed, notifies its network acceptance area reselection request; Described subscriber equipment sends the sub-district gravity treatment to described target mobile management unit and finishes message, and affirmation sub-district gravity treatment is finished.

Further, said method also can have following characteristics:

In the process that the RRC that described subscriber equipment is initiated after the sub-district gravity treatment is finished connects; described subscriber equipment and described destination service UMTS network come count initialized device COUNT-I, COUNT-C with described START value again; wherein COUNT-I is the counter of network access server signaling quantity that writes down the Integrity Key IK protection of the land radio access web that is subjected to evolution, and COUNT-C is the counter of network access server signaling quantity that writes down the encryption key IK protection of the land radio access web that is subjected to evolution.

The method of the invention is owing to adopt START and START _-NASContinue, and come the initialization associated counter, overcome in the prior art UE between UTRAN and EUTRAN during TAU, the safety defect that the key life cycle is extended with it.

Description of drawings

Fig. 1 moves to EUTRAN when carrying out TAU from UTRAN, the signaling process figure of UE counter initial setting method for embodiment of the invention UE;

Fig. 2 moves to UTRAN when carrying out TAU from EUTRAN, the signaling process figure of counter initial setting method for another embodiment of the present invention UE.

Embodiment

Design of the present invention is: UE moves between different access systems, in the time that the sub-district gravity treatment need being carried out, utilize the START value in the former connecting system, the START value in the initialization goal systems, and when connecting, use the counter in the START value initialization goal systems in the goal systems.

Aim to provide a kind of after UE carries out TAU between UTRAN and the EUTRAN, the initial method of counter, make the sub-key life cycle continue the life span of the preceding his father's key of TAU, and after the TAU success, continue the life span of sub-key that adds up, thereby avoid the life span of sub-key to be extended.

Below in conjunction with the drawings and specific embodiments technical scheme of the present invention is described in detail.

First embodiment

Present embodiment be UE under idle condition, move to EUTRAN from UTRAN, in the time of need carrying out the sub-district gravity treatment, counter is carried out the method that initialization is provided with.Its signaling process may further comprise the steps as shown in Figure 1:

Step 101:UE is to START _-NASCarry out the initialization setting, make START _-NAS=START uses START then _-NASTo COUNT _-NASCarry out the initialization setting;

To COUNT _-NASWhen carrying out initialization and being provided with, be about to START _-NASValue as COUNT _-NASThe value of high-order effective bit, can be expressed as MSB (COUNT with formula _-NAS)=START _-NAS, COUNT _-NASAll the other bit positions be 0.

UE also need use IK and CK to generate K in this step _-ASME, K _NAS-intAnd K _NAS-enc, because need in follow-up TAU request, use this key to carry out integrity protection.

Step 102:UE sends out the TAU request to target MME, simultaneously with START _-NASIssue target MME;

Step 103: target MME sends out context request to source SGSN, and request source SGSN transmits IK, user profile such as CK;

Step 104: source SGSN sends out context response to target MME, and with CK, user related informations such as IK are passed to target MME;

Step 105: target MME uses START _-NASTo COUNT _-NASCarry out the initialization setting;

Here target MME also uses IK and CK to generate K _-ASME, K _NAS-intAnd K _NAS-enc, be used for the encipherment protection of subsequent message.

Step 106: target MME notifies UE, and TAU is accepted;

Step 107:UE sends out TAU and finishes message, confirms that TAU finishes.

Second embodiment

Present embodiment be UE under idle condition, move from EUTRAN and UTRAN, in the time of need carrying out TAU, counter is carried out the method that initialization is provided with.As shown in Figure 2, may further comprise the steps:

When the UMTS network is arrived in step 201:UE decision sub-district gravity treatment, use COUNT _-NASThe START of value initialization and START is set _-NAS, be about to COUNT _-NASThe value (being also referred to as high Bit Significance) of high-order effective bit add that 2 (also can add and be no less than other integers of 1) backs composes and give START here _-NAS, can be expressed as START _-NAS=MSB ₂₀(COUNT _-NASInitialization, START=START are carried out to START simultaneously in)+2 _-NAS

Step 202:UE sends out TAU and asks target SGSN;

Step 203: target SGSN is sent out context request to source MME;

Step 204: source MME sends out context response to target SGSN;

Step 205: target SGSN sends the sub-district gravity treatment to UE to be confirmed, notice UE network has been accepted TAU;

Step 206:UE sends out TAU and finishes acknowledge message.

When the gravity treatment of sub-district, SGSN does not carry out the initialization setting to START, and after UE initiated the RRC connection, UE and SGSN used the COUNT-I of START value initialization, COUNT-C again.

From foregoing description, owing to adopt START and START _-NASContinue, and come the initialization associated counter, overcome in the prior art UE between UTRAN and EUTRAN during TAU, the safety defect that the key life cycle is extended with it.

The above is embodiments of the invention only, is not limited to the present invention, and for a person skilled in the art, the present invention can have various changes and variation.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 the claim scope of the present invention.

Claims (5)

1, a kind of initial setting method that is used for cryptographic key existence counter among different access systems is characterized in that, subscriber equipment from the land radio access web of evolution landwards wireless access network move, in the time of need carrying out the sub-district gravity treatment, carry out following steps:

When the UMTS network is arrived in described subscriber equipment decision sub-district gravity treatment, with counter COUNT _-NASHigh Bit Significance add 1 initial value at least as counter START, then, send cell re-selection request to destination service UMTS network;

Wherein, counter START is the Integrity Key IK of land radio access web and the existence counter of encryption key CK, counter COUNT _-NASIt is the Non-Access Stratum integrity protection key K that writes down the land radio access web that is subjected to evolution _NAS-intWith the Confidentiality protection key K _NAS-encThe counter of the network access server signaling quantity of protection.

2, initial setting method as claimed in claim 1 is characterized in that:

Described subscriber equipment is earlier with counter COUNT _-NASHigh Bit Significance add 1 at least after, compose to give counter START _-NAS, the value initialization with counter START is counter START then _NASValue; Counter START wherein _-NASBe to be used for recording counter COUNT _-NASThe counter of high Bit Significance.

3, initial setting method as claimed in claim 1 is characterized in that:

Described subscriber equipment is earlier with counter COUNT _-NASHigh Bit Significance add 2 after, compose to give counter START _-NAS, i.e. START=START _-NAS=MSB (COUNT _-NAS)+2; Value initialization with counter START is counter START then _NASValue, counter START wherein _-NASBe to be used for recording counter COUNT _-NASThe counter of high Bit Significance.

4, as claim 1,2 or 3 described initial setting methods, it is characterized in that:

After described destination service UMTS network receives that described subscriber equipment sends cell re-selection request, send context request to the source mobile management unit; After described source mobile management unit is received, send context response to described destination service UMTS network; Described destination service UMTS network sends the sub-district gravity treatment to described subscriber equipment again to be confirmed, notifies its network acceptance area reselection request; Described subscriber equipment sends the sub-district gravity treatment to described target mobile management unit and finishes message, and affirmation sub-district gravity treatment is finished.

5, as claim 1,2 or 3 described initial setting methods, it is characterized in that:

In the process that the RRC that described subscriber equipment is initiated after the sub-district gravity treatment is finished connects; described subscriber equipment and described destination service UMTS network come count initialized device COUNT-I, COUNT-C with described START value again; wherein COUNT-I is the counter of network access server signaling quantity that writes down the Integrity Key IK protection of the land radio access web that is subjected to evolution, and COUNT-C is the counter of network access server signaling quantity that writes down the encryption key IK protection of the land radio access web that is subjected to evolution.

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