DESCRIPTION
Title of Invention
GROUP AUTHENTICATION AND KEY MANAGEMENT FOR MTC
Technical Field
[0001]
The present invention relates to a security solution for group authentication in
Machine-Type Communication (MTC). This solution can provide an efficient way for network
to perform mutual authentication with all the group MTC UEs (User Equipments).
Bacl^round Art
[0002]
The 3GPP (3rd Generation Partnership Project) architecture of MTC is disclosed in NPL
1. The AKA (Authentication and Key Management) procedure disclosed in NPL 2 can be
performed individually to achieve mutual authentication.
Citation List
Non Patent Literature
[0003]
NPL 1: 3GPP TS 23.682, "Architecture enhancements to facilitate communications with
packet data networks and applications (Release 11)", Vll.2.0, 2012-09
NPL 2: 3GPP TS 33.401, "3GPP System Architecture Evolution (SAE); Security
architecture (Release 12)", V12.5.1, 2012-10
NPL 3: 3GPP TR 33.868, "Security aspects of Machine-Type and other Mobile Data
Applications Communications Enhancements; (Release 12)", VO.10.0, 2012-09
Patent Literature
[0004]
PTL 1: International Patent Publication No. WO 2012/018130
Summary of Invention
Technical Problem
[0005]
However, inventors of this application have found that there are few issues for MTC
UEs as follows:
1) Authentication happens at the same time can overload the network.
2) MTC UE needs to have mutual authentication to the network not only as an
individual but also as a group member. The security requirement has been disclosed in NPL 3:
"UE can be verified as legitimate member of a MTC group".
3) New keys are needed for securing group messaging.
[0006]
The solution proposed in this invention is focused on will be described in the following
sections.
Solution to Problem
[0007]
A few assumptions are made for the present invention as follows:
1) SCS (Service Capability Server) knows the external group ID (identifier) and can use
it to activate a group and communicate with the group of MTC UEs.
2) MTC UEs are preconfigured with the group ID(s) that they can belong to and
communicate through.
3) MTC UEs are optionally preconfigured with a public group key.
[0008]
Note, in the description of this invention, MME (Mobility Management Entity) is used
as an example but the mechanism should be the same for SGSN (Serving GPRS (General Packet
Radio Service) Support Node) and MSC (Mobile Switching Centre).
[0009]
When the SCS first time actives a group of MTC UEs, it triggers the UEs by sending a
trigger message with indication of trigger.type- 'activate group". When MTC-IWF (MTC
Inter-Working Function) receives such type of trigger it will request subscriber information from
HSS (Home Subscriber Server) by sending Subscriber Information Request. HSS will perform
verification of whether such group exists and whether it can be triggered by the SCS and finds
which are the possible MMEs. HSS pushes the routing information of MMEs to MTC-IWF,
MTC-IWF will then forward the trigger to the serving MMEs. MME forwards it to group GW
(gateway) and group GWbroadcasts it to the UEs. The trigger contains local group ID and
trigger ID. Only UEs which preconfigured the same group ID should respond to it and start the
Attach procedure.
[0010]
Since this is first time UE attaches to network, AKA procedure will be started by
network. The concept is to re-use AKA procedure disclosed in NPL 2. However, instead of
authenticating the UE individually, MME sends all the authentication request in a concatenated
message and group GW distributes that to UEs. In the same way for Authentication Response,
group GWreceives them from all the UEs and sends them in a concatenated message to MME.
By doing this, the network usage can be reduced.
[0011]
Verification of whether UE belongs to this group is carried at network before
authentication.
[0012]
The group gateway (GW) was proposed in a separate invention of PTL 1. The group
GWreceives (group) message and send it to MTC devices. It sends concatenated messages for
MTC device communicating with network or SCS. It can be an independent node or a logical
function installed in eNB (evolved Node B), MME/SGSN/MSC, HSS or MTC-IWF. When it is
installed in eNB, broadcasting is used for sending messages to UEs. When it is installed in
MME/SGSN/MSC, multicasting is used. Note that each of the MTC Device and the
above-described MTC UE is a UE equipped for MTC, therefore the terms "MTC Device" and
"MTC UE" are the same in meaning through the whole description of this application.
Advantageous Effects of Invention
[0013]
According to the present invention, it is possible to solve at least one of the
above-mentioned issues.
Brief Description of Drawings
[0014]
[Fig. 1]
Fig. 1 is a block diagram showing a configuration example of a communication system
according to an exemplary embodiment of the present invention.
[Fig. 2]
Fig. 2 is a sequence diagram showing a part of an operation example of the
communication system according to the exemplary embodiment.
[Fig. 3]
Fig. 3 is a sequence diagram showing the remaining part of the operation example of the
communication system according to the exemplary embodiment.
[Fig. 4]
Fig. 4 is a block diagram showing a configuration example of an MTC device according
to the exemplary embodiment.
[Fig. 5]
Fig. 5 is a block diagram showing a configuration example of a gateway according to
the exemplary embodiment.
[Fig. 6]
Fig. 6 is a block diagram showing a configuration example of a first network node
according to the exemplary embodiment.
[Fig. 7]
Fig. 7 is a block diagram showing a configuration example of a second network node
according to the exemplary embodiment.
[Fig. 8]
Fig. 8 is a block diagram showing a configuration example of a third network node
according to the exemplary embodiment.
[Fig. 9]
Fig. 9 is a block diagram showing a configuration example of a server according to the
exemplary embodiment.
Description of Embodiments
[0015]
Hereinafter, an exemplary embodiment of the present invention will be described with
reference to the accompanying drawings.
[0016]
As shown in Fig. 1, a communication system according to this exemplary embodiment
includes a core network (3GPP network), and a plurality of MTC UEs 10 which connect to the
core network through a RAN (Radio Access Network). While the illustration is omitted, the
RAN is formed by a plurality of base stations (i.e., eNBs).
[0017]
The MTC UEs 10 attach to the core network. The MTC UEs 10 can host one or
multiple MTC Applications. The corresponding MTC Applications are hosted on one or
multiple ASs (Application Servers).
[0018]
Further, the core network includes, as network elements, an MME 30, an HSS 40 and an
MTC-IWF 50. The MTC-IWF 50 serves as a gateway to the core network for an SCS 60.
The HSS 40 stores subscription information on a group of MTC UEs. The MME 30, as well as
an SGSN and an MSC relay traffic between the MTC UEs 10 and the MTC-IWF 50.
[0019]
Furthermore, a group GW 20 shown in Figs. 2 and 3 serves as a gateway to the core
network for the MTC UEs 10. The group GW 20 may be an independent node placed within
the core network or the RAN, or may be a logical function installed in the eNB, MME, SGSN,
MSC, HSS or MTC-IWF.
[0020]
Next, operations in this exemplary embodiment will be described with reference to Figs.
2 and 3. Figs. 2 and 3 gives detailed message sequence description of how the SCS 60 activates
a group of devices (MTC UEs) which are pre-configured with a local group ID.
[0021]
Step S1: SCS 60 has stored the external group ID.
[0022]
Step S2: HSS 40 has subscription information of a group and its member UEs 10_1 to
10_n (n>2).
[0023]
Step S3: Each of UEs 10_1 to 10_n in the group has pre-configured local group ID and
optionally public group key.
[0024]
Step S4: SCS 60 sends a trigger to MTC-IWF 50, with trigger type of activate group,
including external group ID, SCS ID and trigger ID.
[0025]
Step S5: MTC-IWF 50 sends Subscriber Information Request, reuse the message
disclosed in NPL 1, with external group ID, indication of activate group request and the source
SCS ID.
[0026]
Step S6: HSS 40 performs the verification of whether the external group ID is valid,
whether any data available about this group, if SCS can trigger to activate the group, is there
already a local group ID mapped to it.
[0027]
Step S7: After proper verification, HSS 40 sends the Subscriber Information Response
message to MTC-IWF 50, with local group ID and serving MMEs.
[0028]
Step S8: Optionally, HSS 40 can send information necessary for the verification and
MTC-IWF 50 performs the verification.
[0029]
Step S9: MTC-IWF 50 forwards the trigger message to MME 30, with local group ID
and trigger method of broadcast.
[0030]
Step S10: MME 30 retrieves the MTC UE subscription data and the private group key.
[0031]
Step S11: MME 30 forwards the trigger to group GW 20.
[0032]
Step SI2: Group GW 20 broadcast the trigger, with a trigger type of e.g. callAttach,
which UEs 10 1 to 10_n can understand. The trigger includes local group ID and trigger ID.
[0033]
Step S13: When each of UEs 10 1 to 10_n receives the trigger, it verifies if the local
group ID in the broadcast trigger is the same with the one it has pre-configured. If not, it
ignores the broadcast. If the group ID is the same, each of UEs 10_1 to 10_n starts the attach
procedure.
[0034]
Step S 4 : UEs 10 1 to 10_n which have the same local group ID send Attach Request
with IMSI as in standardized Attach Request and also the trigger ID it received.
[0035]
Step SI5: Group GW 20 sends a concatenated Attach Request to MME 30, it contains
the Attach Request messages from all the UEs.
[0036]
Step SI6: MME 30 performs the verification of whether the timer of response is expired,
whether the UEs whom responded belong to the group and which are the UEs have not
responded yet.
[0037]
Step SI7: MME 30 sends Authentication Request (reusing standardized message
disclosed in NPL 2, but in a concatenated message.
[0038]
Step SI 8: Group GW 20 distributes the Authentication Request to the UEs 10 1 to 10_n,
this can be optionally protected by private group key such that UEs 10 1 to 10_n can verify
whether the group GW 20 is an authenticated network element, with their pre-configured public
group key.
[0039]
Step SI9: Each of UEs 10 1 to 10_n responds Authentication Response.
[0040]
Step S20: Group GW 20 sends Authentication Response from all the UEs 10 1 to 10_n
in a concatenated message.
[0041]
Step S21 : MME 30 performs authentication for the UEs 10_1 to 10_n.
[0042]
Step S22: MME 30 sends Authentication Reject messages to UE, if the authentication
failed.
[0043]
Steps S23 and S24: MME 30 reports authentication failure to SCS 60 through
MTC-IWF 50.
[0044]
Step S25: NAS (Non Access Stratum) and AS key management according to
standardized procedure disclosed in NPL 2, with MME 30 sending the concatenated message and
group GW 20 distributing it to UEs 10_1 to 10_n for downlink and group GW 20 concatenating
the messages from UEs 10_1 to 10_n and sending to MME 30 for uplink.
[0045]
Step S26a: MME 30 sends NAS SMC (Security Mode Command) messages in
concatenated message which includes the new group keys encrypted by NAS key.
[0046]
Step S26b: Group GW 20 distributes the NAS SMC message containing encrypted new
group keys to the UEs 10_1 to 10_n.
[0047]
Step S27a: MME 30 sends Attach Accept messages in concatenated message which
includes the new group keys.
[0048]
Step S27b: Group GW 20 distributes the Attach Accept message with new group keys to
the UEs 10_1 to 10_n.
[0049]
Note that the new group keys in Step S26 and Step S27 are the same as in our previous
patent file PTL 1, that they are a pair of keys for confidentiality and integrity protection.
[0050]
Next, configuration examples of the MTC UE 10, the group GW 20, the MME 30, the
HSS 40, the MTC-IWF 50 and the SCS 60 according to this exemplary embodiment will be
described with reference to Figs. 4 to 9. Note that in the following explanation, there will be
described only elements which specific to this exemplary embodiment. However, it will be
understood that the MTC UE 10, the group GW 20, the MME 30, the HSS 40, the MTC-IWF 50
and the SCS 60 also include elements for functioning as typical MTC UE, GW, MME, HSS,
MTC-IWF and SCS, respectively.
[0051]
As shown in Fig. 4, the MTC UE 10 includes an inclusion unit 11. The inclusion unit
11 includes the received trigger ID in the Attach Request message as shown at step S14 in Fig. 3.
This inclusion unit 11 can be configured by, for example, a transceiver which conducts
communication with the SCS 60 through the core network, and a controller such as a CPU
(Central Processing Unit) which controls this transceiver.
[0052]
As shown in Fig. 5, the group GW 20 includes at least one of an addition unit 2 1 and a
protection unit 22. The addition unit 2 1 adds the indication of trigger type- 'callAttach" to the
trigger message as shown at step S12 in Fig. 2. The protection unit 22 protects the
Authentication Request message with the private group key as shown at step SI8 in Fig. 3.
Note that these units 2 1 and 22 are mutually connected with each other through a bus or the like.
These units 2 1 and 22 can be configured by, for example, a transceiver which conducts
communication with the MTC UE 10, and a controller such as a CPU which controls this
transceiver.
[0053]
As shown in Fig. 6, the MME 30 includes at least an inclusion unit 31. For example,
the inclusion unit 31 includes the new group keys in the Attach Accept message as shown at step
S27 in Fig. 3. Alternatively, the inclusion unit 31 includes the new group keys in the NAS
SMC message as shown at step S26 in Fig. 3. In the latter case, it is preferable that the MME
30 further includes an encryption unit 34. The encryption unit 34 encrypts the new group keys
with the NAS keys. In addition to or as a substitute for the encryption unit 34, the MME 30 can
include a concatenation unit 32 and a send unit 33. The concatenation unit 32 concatenates the
messages addressed to the MTC UEs 10 1 to 10_n as shown at Steps S17 and S25 in Fig. 3.
The send unit 33 sends the concatenated message to the group GW20. Note that these units 31
to 34 are mutually connected with each other through a bus or the like. These units 31 to 34
can be configured by, for example, a transceiver which conducts communication with the MTC
UE 10 through the group GW20, and a controller such as a CPU which controls this transceiver.
[0054]
As shown in Fig. 7, the HSS 40 includes a verification unit 4 1 which performs the
verification as shown at step S6 in Fig. 2. This verification unit 4 1 can be configured by, for
example, a transceiver which conducts communication with the MTC-IWF 50, and a controller
such as a CPU which controls this transceiver.
[0055]
As shown in Fig. 8, the MTC-IWF 50 includes an instruction unit 51. The instruction
unit 51 instructs the group GW20 to broadcast the trigger message, for example by using the
indication of trigger method- 'broadcast" as shown at step S9 in Fig. 2. This instruction unit 5 1
can be configured by, for example, a transceiver which conducts communication with the group
GW20 through the MME 30, and a controller such as a CPU which controls this transceiver.
[0056]
As shown in Fig. 9, the SCS 60 includes a send unit 61. The send unit 6 1 sends, to the
MTC-IWF 50, the trigger message includes the indication of trigger type- 'activate group" as
shown at step S4 in Fig. 2. This send unit 6 1 can be configured by, for example, a transceiver
which conducts communication with the MTC UE 10 through the core network, and a controller
such as a CPU which controls this transceiver.
[0057]
Note that the present invention is not limited to the above-mentioned exemplary
embodiment, and it is obvious that various modifications can be made by those of ordinary skill
in the art based on the recitation of the claims.
[0058]
The whole or part of the exemplary embodiment disclosed above can be described as,
but not limited to, the following supplementary notes.
[0059]
(Supplementary note 1)
Introduced a new trigger type "activate group" in the trigger message, which is sent over
interface Tsp, T5, and the interface between MME/SGSN/MSC and UE.
[0060]
(Supplementary note 2)
Introduced "broadcast" as a new trigger delivery method.
[0061]
(Supplementary note 3)
Authentication Request can be protected by private group key.
[0062]
(Supplementary note 4)
Introduced trigger field in the broadcasting message to indicate it is to call MTC UE to
start Attach procedure.
[0063]
(Supplementary note 5)
New function for HSS of verification to determine whether the external group is valid.
[0064]
(Supplementary note 6)
Included "trigger ID" in Attach Request message.
[0065]
(Supplementary note 7)
Sending the encrypted new group keys in NAS SMC message.
[0066]
(Supplementary note 8)
Or sending the new group keys in Attach Accept message which has NAS security
protection.
[0067]
This application is based upon and claims the benefit of priority from Japanese patent
application No. 2012-267255, filed on December 6, 2012, the disclosure of which is incorporated
herein in its entirety by reference.
Reference Signs List
[0068]
10, 10_l-10_n MTC UE
11, 3 1 INCLUSION UNIT
20 GROUP GW
2 1 ADDITION UNIT
22 PROTECTION UNIT
30 MME
CONCATENATIONUNIT
, 6 1 SEND UNIT
ENCRYPTION UNIT
HSS
VERIFICATIONUNIT
MTC-IWF
INSTRUCTION UNIT
SCS

CLAIMS
[Claim 1]
A communication system comprising:
a group of MTC (Machine-Type-Communication) devices;
a server that can communicate with the MTC devices; and
a network that relays traffic between the MTC devices and the server,
wherein the server send a trigger message for activating the group to the MTC devices
through the network.
[Claim 2]
The communication system according to Claim 1, wherein the network includes a node
that verifies whether or not to transfer the trigger message to the given MTC devices, based on
subscription information on the group.
[Claim 3]
A communication system comprising:
a group of MTC (Machine-Type-Communication) devices that communicate with a
server through a network;
a gateway to the network for the MTC devices; and
a network node that relays traffic between the gateway and the server,
wherein the network node instructs the gateway to broadcast a trigger message
addressed to the group,
the gateway broadcast the trigger message in accordance with the instruction.
[Claim 4]
The communication system according to Claim 3, wherein the gateway adds, to the
trigger message, a field for requesting each of the MTC devices to attach to the network.
[Claim 5]
A communication system comprising:
a group of MTC (Machine-Type-Communication) devices;
a server that can communicate with the MTC devices; and
a network that relays traffic between the MTC devices and the server,
wherein the network includes a node that protects a group trigger message to be
transmitted to each of the MTC devices, by use of a private key for the group.
[Claim 6]
A communication system comprising:
a group of MTC (Machine-Type-Communication) devices that communicate with a
server through a network;
a gateway to the network for the MTC devices; and
a network node that relays traffic between the gateway and the server,
wherein the network node includes, in messages addressed to the MTC devices, keys for
each of the MTC devices to securely conduct group communication with the network,
concatenates the messages, and sends the concatenated message to the gateway,
wherein the gateway distributes, to the MTC devices, the messages included in the
concatenated message.
[Claim 7]
A communication system comprising:
a group of MTC (Machine-Type-Communication) devices that communicate with a
server; and
a network that relays traffic between the MTC devices and the server,
wherein the network includes a node that includes, in messages addressed to the MTC
devices, keys for each of the MTC devices to securely conduct group communication with the
network, and
each of the messages comprises a securely protected message indicating that each of the
MTC devices is accepted to attach to the network.
[Claim 8]
A communication system comprising:
a group of MTC (Machine-Type-Communication) devices that communicate with a
server; and
a network that relays traffic between the MTC devices and the server,
wherein the network includes a node that encrypts keys for each of the MTC devices to
securely conduct group communication with the network, and that includes the encrypted keys in
messages addressed to the MTC devices.
[Claim 9]
A communication system comprising:
a group of MTC (Machine-Type-Communication) devices that communicate with a
server through a network,
wherein each of the MTC devices includes, in a request for attaching to the network, an
identifier of a trigger message received at each of the MTC devices.
[Claim 10]
A server that can communicate with a group of MTC (Machine-Type-Communication)
devices through a network relaying traffic between the MTC devices and the server, the server
comprising:
send means for sending a trigger message for activating the group to the MTC devices
through the network.
[Claim 11]
The server according to Claim 10, comprising an SCS (Service Capability Server).
[Claim 12]
A node included in a network that relays between a group of MTC
(Machine-Type-Communication) devices and a server, the node comprising:
verification means for verifying whether or not to transfer a trigger message to the given
MTC devices based on subscription information on the group, the trigger message being for
activating the group and received from the server.
[Claim 13]
The node according to Claim 12, comprising an HSS (Home Subscriber Server).
[Claim 14]
A node included in a network that relays between a group of MTC
(Machine-Type-Communication) devices and a server, the node comprising:
instruction means for instructing a gateway to broadcast a trigger message addressed to
the group, the gateway serving as a gateway to the network for the MTC devices.
[Claim 15]
The node according to Claim 14, comprising an MTC-IWF (MTC Inter-Working
Function).
[Claim 16]
A node included in a network that relays between a group of MTC
(Machine-Type-Communication) devices and a server, the node comprising:
inclusion means for including, in messages addressed to the MTC devices, keys for each
of the MTC devices to securely conduct group communication with the network;
concatenation means for concatenating the messages; and
send means for sending the concatenated message to a gateway to the network for the
MTC devices.
[Claim 17]
Anode included in a network that relays between a group of MTC
(Machine-Type-Communication) devices and a server, the node comprising:
inclusion means for including, in messages addressed to the MTC devices, keys for each
of the MTC devices to securely conduct group communication with the network,
wherein each of the messages comprises a securely protected message indicating that
each of the MTC devices is accepted to attach to the network.
[Claim 18]
A node included in a network that relays between a group of MTC
(Machine-Type-Communication) devices and a server, the node comprising:
encryption means for encrypting keys for each of the MTC devices to securely conduct
group communication with the network; and
inclusion means for including the encrypted keys in messages addressed to the MTC
devices.
[Claim 19]
The node according to any one of Claims 16 to 18, comprising an MME (Mobility
Management Entity).
[Claim 20]
A gateway to a network for a group of MTC (Machine-Type-Communication) devices
that communicate with a server through the network, the gateway comprising:
addition means for adding, to a trigger message addressed to the group, a field for
requesting each of the MTC devices to attach to the network.
[Claim 21]
A gateway to a network for a group of MTC (Machine-Type-Communication) devices
that communicate with a server through the network, the gateway comprising:
protection means for protecting a group trigger message to be transmitted to each of the
MTC devices, by use of a private key for the group.
[Claim 22]
An MTC (Machine-Type-Communication) device that is grouped together with one or
more different MTC devices to communicate with a server through a network, the MTC device
comprising:
inclusion means for including, in a request for attaching to the network, an identifier of
a trigger message received at the MTC device.
[Claim 23]
Amethod of controlling operations in a server that can communicate with a group of
MTC (Machine-Type-Communication) devices through a network relaying traffic between the
MTC devices and the server, the method comprising:
sending a trigger message for activating the group to the MTC devices through the
network.
[Claim 24]
A method of controlling operations in a node included in a network that relays between
a group of MTC (Machine-Type-Communication) devices and a server, the method comprising:
verifying whether or not to transfer a trigger message to the given MTC devices based
on subscription information on the group, the trigger message being for activating the group and
received from the server.
[Claim 25]
Amethod of controlling operations in a node included in a network that relays between
a group of MTC (Machine-Type-Communication) devices and a server, the method comprising:
instructing a gateway to broadcast a trigger message addressed to the group, the
gateway serving as a gateway to the network for the MTC devices.
[Claim 26]
Amethod of controlling operations in a node included in a network that relays between
a group of MTC (Machine-Type-Communication) devices and a server, the method comprising:
including, in messages addressed to the MTC devices, keys for each of the MTC
devices to securely conduct group communication with the network;
concatenating the messages; and
sending the concatenated message to a gateway to the network for the MTC devices.
[Claim 27]
A method of controlling operations in a node included in a network that relays between
a group of MTC (Machine-Type-Communication) devices and a server, the method comprising:
including, in messages addressed to the MTC devices, keys for each of the MTC
devices to securely conduct group communication with the network,
wherein each of the messages comprises a securely protected message indicating that
each of the MTC devices is accepted to attach to the network.
[Claim 28]
A method of controlling operation in a node included in a network that relays between a
group of MTC (Machine-Type-Commumcation) devices and a server, the method comprising:
encrypting keys for each of the MTC devices to securely conduct group communication
with the network; and
including the encrypted keys in messages addressed to the MTC devices.
[Claim 29]
A method of controlling operations in a gateway to a network for a group of MTC
(Machine-Type-Communication) devices that communicate with a server through the network,
the method comprising:
adding, to a trigger message addressed to the group, a field for requesting each of the
MTC devices to attach to the network.
[Claim 30]
Amethod of controlling operations in a gateway to a network for a group of MTC
(Machine-Type-Communication) devices that communicate with a server through the network,
the method comprising:
protecting a group trigger message to be transmitted to each of the MTC devices, by use
of a private key for the group.
[Claim 31]
A method of controlling operations in an MTC (Machine-Type-Communication) device
that is grouped together with one or more different MTC devices to communicate with a server
through a network, the method comprising:
including, in a request for attaching to the network, an identifier of a trigger message
received at the MTC device.