Description
Title of Invention: SECURE SYSTEM AND METHOD OF
MAKING SECURE COMMUNICATION
Technical Field
[0001] This invention relates to a secure system and a method of making a secure commu
nication, and more specifically, to a secure system that provides a method of making a
secure discovery to form a group and secure communication between members of a
specific group.
Background Art
[0002] 3GPP (3rd Generation Partnership Project) has started to study Proximity based
Services (ProSe) for both commercial and public safety uses. 3GPP SA1 (Services
Working Group) has initiated some security requirements for secure communication,
UE (User Equipment) identity, and privacy protection.
[0003] ProSe represents a recent and enormous socio-technological trend. The principle of
these applications is to discover instances of the applications running in devices that
are within proximity of each other, and ultimately to also exchange application-related
data. In parallel to this, there is interest in proximity-based discovery and commu
nications in the public safety community.
[0004] ProSe communication can provide services to the UEs in proximity via an eNB
(Evolved Node B) or without the eNB. The SA1 requires that the ProSe service be
provided to UEs with or without network coverage. The UEs can discover other nearby
UEs or be discovered by other UEs, and they can communicate with each other. Some
use cases can be found in NPL 1.
Citation List
Non Patent Literature
[0005] NPL 1: 3GPP TR 22.803 Feasibility study for Proximity Services (ProSe), (Release
12)
Summary of Invention
Technical Problem
[0006] However, despite the security issues involving group management, discovery, au
thentication, authorization, key management, and communication termination, as well
as privacy issues, 3GPP SA3 offers no security solution.
Solution to Problem
[0007] The present invention has been made to present an overall security solution for the
above-mentioned security issues.
[0008] In one embodiment, there is provided a secure system including a plurality of User
Equipments (UEs), including a requesting device which requests a communication;
and a receiving device which receives a communication request from the requesting
device. The requesting device and the receiving device are members of a specific
group or potential members which join the specific group when the requesting device
discovers the receiving device. The requesting device and the receiving device satisfy
one or more requirements for security, the requirements for the security including a
first requirement that the requesting device are authorized by a network to discover
receiving devices that are in the specific group or to form the specific group, a second
requirement that the requesting device and the receiving device in the specific group
are able to perform a mutual authentication over a direct interface, and to perform au
thorization with a proof provided by a network, and a third requirement that the re
questing and receiving device are able to secure the direct communication.
[0009] In another embodiment, there is provided a method of making a secure commu
nication provided by a secure system including a requesting device which requests a
communication, and a receiving device which receives the communication request
from the requesting device, the method including joining a specific group before or
after the requesting device discovers the receiving device, and satisfying one or more
requirements for security. The requirements for the security includes a first r e
quirement that the requesting device are authorized by a network to discover receiving
devices that in the specific group or to form the specific group, a second requirement
that the requesting device and the receiving device in the specific group are able to
perform a mutual authentication over a direct interface, and to perform authorization
with a proof provided by a network, and a third requirement that the requesting and
receiving device are able to secure the direct communication.
Advantageous Effects of Invention
[0010] A secure system and a method of making a secure communication can present an
overall security solution for security issues.
Brief Description of Drawings
[001 1] The above and other objects, advantages and features of the present invention will be
more apparent from the following description of certain preferred embodiments taken
in conjunction with the accompanying drawings, in which:
[fig.lA]Fig. 1A is a schematic view showing the ProSe Communication scenario in
NPL 1;
[fig.lB]Fig. IB is a schematic view showing the ProSe Communication scenario in
NPL 1;
[fig.2]Fig. 2 is a schematic view showing an example of the systems which provide a
method of making a secure communication according to an exemplary embodiment of
the present invention;
[fig.3]Fig. 3 is a schematic view showing a secure system of an exemplary em
bodiment of the present invention;
[fig.4]Fig. 4 is a sequence diagram explaining a method of making a secure commu
nication of an exemplary embodiment of the invention;
[fig.5A]Fig. 5A is a schematic view showing a One-to-one session;
[fig.5B]Fig. 5B is a schematic view showing a One-to-many session; and
[fig.5C]Fig. 5C is a schematic view showing a Many-to-many session.
Description of Embodiments
[0012] For purposes of the description hereinafter, the terms "upper", "lower", "right", "left",
"vertical", "horizontal", "top", "bottom", "lateral", "longitudinal", and derivatives
thereof shall relate to the invention as it is oriented in the drawing figures. However, it
is to be understood that the invention may assume alternative variations and step
sequences, except where expressly specified to the contrary. It is also to be understood
that the specific devices and processes illustrated in the attached drawings, and
described in the following specification, are simply exemplary embodiments of the
invention. Hence, specific dimensions and other physical characteristics related to
exemplary embodiments disclosed herein are not to be considered as limiting.
[0013] In the exemplary embodiments, though the security solutions with a focus on
specifically direct communication, discovery, and communication will be explained,
the solutions can be applied to other communications as well.
[0014] Firstly, definitions given in 3GPP TR 21.905: "Vocabulary for 3GPP Specifications"
will be explained.
[0015] ProSe Direct Communication:
A communication between two or more UEs in proximity that are ProSe-enabled, by
means of user plane transmission using E-UTRA technology via a path not traversing
any network node.
[0016] ProSe-enabled UE:
A UE that supports ProSe requirements and associated procedures. Unless explicitly
stated otherwise, a Prose-enabled UE refers both to a non-public safety UE and a
public safety UE.
[0017] ProSe-enabled Public Safety UE:
A ProSe-enabled UE that also supports ProSe procedures and capabilities specific to
Public Safety.
[0018] ProSe-enabled non-public safety UE:
A UE that supports ProSe procedures but not capabilities specific to public safety.
[0019] ProSe Direct Discovery:
A procedure employed by a ProSe-enabled UE to discover other ProSe-enabled UEs
in its vicinity by using only the capabilities of the two UEs with rel.12 E-UTRA
technology.
[0020] EPC-level ProSe Discovery:
A process by which the EPC determines the proximity of two ProSe-enabled UEs
and informs them of their proximity.
[0021] Figs. 1A and IB are schematic views showing the ProSe Communication scenarios
in NPL 1. When a UE 11 and a UE 12 which are involved in the ProSe Commu
nication are served by the same eNB 19 and network coverage is available, a system
100a can decide to perform ProSe Communication using control information
exchanged between the UEs 11, 12, eNB 19 and an EPC (Evolved Packet Core) 14
(e.g., session management, authorization, security) as shown by the solid arrows in Fig.
1A. For charging, modifications should be minimized with respect to the existing ar
chitecture. The UEs 11 and 12 can in addition exchange control signaling via the ProSe
Communication path as shown by the dashed arrow in Fig. 1A.
[0022] When the UEs 11 and 12 involved in the ProSe Communication are served by
different eNBs 19, 20 and network coverage is available, a system 100b can decide to
perform ProSe Communication using control information exchanged between the UEs
11, 12, eNB 19 and the EPC 14 (e.g., session management, authorization, security) as
shown by the solid arrows in Fig. IB. In this configuration, the eNBs 11 and 12 may
coordinate with each other through the EPC 14 or communicate directly for radio
resource management as shown by the dashed arrow between the eNBs 11 and 12 in
Fig. IB. For charging, signaling modifications should be minimized with respect to the
existing architecture. The UEs 1 1 and 12 can in addition exchange control signaling
via the ProSe Communication path as shown by the dashed arrow between the UE 11
and the UE 12 in Fig. IB.
[0023] If network coverage is available for a subset of the UEs, one or more Public Safety
UEs may relay the radio resource management control information for other UEs that
do not have network coverage.
[0024] If network coverage is not available, the control path can exist directly between
Public Safety UEs. In this configuration, the Public Safety UEs can rely on preconfigured
radio resources to establish and maintain the ProSe Communication. Alter
natively, a Public Safety Radio Resource Management Function, which can reside in a
Public Safety UE, can manage the allocation of radio resources for Public Safety ProSe
Communication.
[0025] Fig. 2 is a schematic view showing an example of the systems which provide a
method of making a secure communication according to an exemplary embodiment of
the present invention. As shown in Fig. 2, a system 10 includes the UE 11, the UE 12,
an E-UTERN 13, the EPC 14, a ProSe Function 15, a ProSe APP Server 16, a ProSe
APP 17, and a ProSe APP 18.
[0026] The UE 11 and the UE 12 can communicate through a PC5, the UE 11 and the EUTERN
13 communicate through LTE-Uul, and the UE 12 can communicate with the
E-UTERN 13 and the ProSe Function 15 through LTE-Uu2 and a PC3, respectively.
The EPC 14 and the ProSe Function 15 can communicate through a PC4, the ProSe
APP server 16 can communicate with the EPC 14 and the ProSe APP 18 through a
SGI and a PCI, respectively, and the ProSe Function 15 can communicate by itself
through a PC6.
[0027] As described above, existing keys can be used when using an infrastructure, i.e., via
eNodeB. However, a new solution is needed for device-to-device direct discovery and
communication; for example, a key can be sent from the network to communicating
parties, a key can be created between communicating parties, or a similar algorithm for
negotiation can be used directly or via the network. Further, a new solution is also
needed for the security over the unlicensed spectrum.
[0028] Two different modes for ProSe Direct Communication one-to-one are supported:
Network independent direct communication: This mode of operation for ProSe
Direct Communication does not require any network assistance to authorize the
connection and communication is performed by using only functionality and in
formation local to the UE. This mode is applicable only to pre- authorized ProSeenabled
Public Safety UEs, regardless of whether the UEs are served by E-UTRAN or
not.
[0029] Network authorized direct communication: This mode of operation for ProSe Direct
Communication always requires network assistance and may also be applicable when
only one UE is "served by E-UTRAN" for Public safety UEs. For non-Public Safety
UEs both UEs must be "served by E-UTRAN".
[0030] PCI:
It is the reference point between the ProSe application 18 in the UE 12 and in the
ProSe App Server 16. It is used to define application level requirements.
[0031] PC2:
It is the reference point between the ProSe App Server 16 and the ProSe Function 15.
It is used to define the interaction between the ProSe App Server 16 and ProSe func
tionality provided by the 3GPP EPS via the ProSe Function 15. One example of use of
it may be for application data updates for a ProSe database in the ProSe Function 15.
Another example of use of it may be data for use by the ProSe App Server 16 in interworking
between 3GPP functionality and application data, e.g. name translation.
[0032] PC3:
It is the reference point between the UE 12 and the ProSe Function 15. It is used to
define the interaction between the UE 12 and the ProSe Function 15. An example of
use of it is for configuration for ProSe discovery and communication.
[0033] PC4:
It is the reference point between the EPC 14 and the ProSe Function 15. It is used to
define the interaction between the EPC 14 and the ProSe Function 15. Possible use
cases of it may be when setting up a one-to-one communication path between UEs or
when validating ProSe services (authorization) for session management or mobility
management in real time.
[0034] PC5:
It is the reference point between the UE 11 to the UE 12 used for control and user
plane for discovery and communication, for relay and one-to-one communication
(between UEs directly and between UEs over LTE-Uu).
[0035] PC6:
This reference point may be used for functions such as ProSe Discovery between
users which are subscribed to different PLMNs.
[0036] SGi:
In addition to the relevant functions defined in TS 29.061 [10] via SGi, it may be
used for application data and application level control information exchange.
[0037] Fig. 3 is a schematic view showing a secure system of an exemplary embodiment of
the present invention. As shown in Fig. 3, a secure system 1 of an exemplary em
bodiment of the present invention includes one or more requesting UEs LOl, an
operator network L02, and one or more receiving UEs L03. A method of performing a
secure communication includes steps of a secure group management LI, a secure
discovery L2, an initial authorization L3, an authentication L4, an authorization L5, a
security association establishment L6, a secure communication L7, and a termination
L8, which are performed between UEs (the requesting UE LOl, the receiving UE L03)
with or without interacting with the operator network L02.
[0038] Assuming that the network coverage is available for UEs, broadcasting is presented
as an example in this exemplary embodiment, but this exemplary embodiment also
applies to multiple-casting and one-to-one communications as shown in Figs. 1A, IB,
and 2.
[0039] From setting up of a group till communication termination, security is needed in each
step as described below. Note that steps LI - L 4 can be in a different order depending
on the service or application.
[0040] LI: Secure group management
Members can join securely, members can leave securely, and an authorization level
of service and each of the members, and any other required information can be
modified securely.
[0041] L2: Secure discovery should happen
If discovery is not secured, a device may start communication with a wrong party or
a rogue device, with the result that masquerading attacks can happen that in turn could
lead to fraudulent charging. For this purpose, the discovery related communication
must be secured, i.e., a UE authenticates identity of other UEs in proximity; integrity
protection for discovery and a device should be able to authenticate the message.
[0042] L3: Initial Authorization
The initial authorization based on secure discovery will lead to the decision that the
discovered device belongs to the group, and thus the next step can start.
[0043] L4: Authentication
Once the device is discovered and authorized as a part of the group, there should be a
mutual authentication; otherwise there is still a scope of attacks.
[0044] L5: Authorization
The next level of authorization will find out what services can be used between the
devices which belong to the same group. For example, a UE is allowed to send and
receive different types of messages or is only allowed to receive broadcasting
messages.
[0045] L6: Security association establishment (Key derivation and management)
The UEs which belong to the same group should have keys to protect their commu
nication such that other UEs which do not belong to the group or an attacker cannot
eavesdrop or alter the messages.
[0046] L7: Secure communication
The communication between UEs in the same group can be protected by the security
association, with integrity and/or confidentiality protection according to the sub
scription service type.
[0047] L8: Termination
The secure termination can provide security when UE(s) suspend or terminate the
communication, or when the entire group communication is terminated.
[0048] The detailed method of performing a secure communication of an exemplary em
bodiment of the invention that fulfills the security requirements will be explained in
the following sections. Fig. 4 is a sequence diagram explaining a method of making a
secure communication between UE 100 and network 200 of an exemplary embodiment
of the invention.
[0049] [1] Group setting and management (LI)
A group can be
(1) two devices communicating with each other (one-to-one), or
(2) more than two devices (one-to-many) where one UE can communicate with the
other devices.
(3) more than two devices (many-to-many) that can communicate with each other.
[0050] A group can be set up for different communication purposes, and group members can
be changed. To form a group, the operator network L02 can check the requesting UE
LOl which requests the UE L03 which it wants to communicate with, verify devices if
they can communicate with each other, and inform the verified devices at both sides
(the requesting UE LOl and the receiving UE L03) of the request and formation.
[0051] Hereinafter one example of creating a group will be explained. As shown in Fig. 4, a
UE 100 requests ProSe subscription to a network 200 and creates a group (Step 1). In
step 1, the UE 100 needs to meet conditions, that is policy, e.g. interest, specific
location etc. Also the network 200 needs to verify whether UE meets conditions, that is
policy, e.g. proximity range, subscription, home network in case of roaming UE, WiFi
or not, ProSe enabled, etc. The group is strictly formed, for example, the members of
the group should be registered in a whitelist, or the group is dynamically formed on a
request from the UE 100, or by the network 200 if the network 200 knows all UE
conditions.
[0052] For creating a secure group, UEs 100 must agree to be a part of the group, and only
"agreed" UEs 100 become group members. A group management includes adding
group members, removing group members, ending the group, and adding temporary
group members. Each UE 100 can see who is in proximity from e.g. a social network
application, and requests for ProSe service, and the ProSe server needs to perform the
authorization, but does not have to perform discovery.
[0053] [2] Discovery - Secure detection of UEs in proximity (L2)
Discovery and group creation in [1] can happen at the same time or be independent
procedure.
There can be following three means that a UE (the requesting UE LOl) can discover
other UEs (the receiving UEs L03) in proximity: (1) Broadcast based, (2) Network
based, and (3) Device service level information based. How secure discovery can be
done will be described as follows.
[0054] [2-1] Broadcast based solution
There are six ways (si - s6) in Broadcast based solution:
[0055] (si) Token
The broadcast message can contain a token that only the given UEs can have. The
token should be used only once to prevent the receiving side from reusing it. In order
to reach that, the UEs can calculate a token each time on receiving the broadcast
message, or the network can inform all the UEs of the token to be used next. This can
be used for such a use case as an information notification kind of service, since the
token can be reused by the receiving side.
[0056] (s2) Signing message
The broadcast message can be signed by a key that can be verified either by the
receiving UEs or by the network for the receiving UEs. Signing can happen by
different key management solutions or it can happen using the current keys for com
municating with the infrastructure network (or derivation from current keys) - a new
key hierarchy might be needed here.
[0057] (s3) Message ID
The broadcast message can have an ID that can be verified during the authentication
and is used initially only for authorization.
[0058] (s4) Random value
The broadcast message can contain a random value that can only be generated by the
network and UE. Verification of the random value is done by the network on behalf of
communicating UEs.
[0059] (s5) Key
Each UE has a specific key belonging to other devices, and thus it sends a potentially
long broadcast or a new type of broadcast that is sent in pieces with encrypted /
integrity protected parts for each UE in the group.
[0060] (s6) Stamp
The broadcast message can be signed with time-stamp and life-time. Note that this
life-time can be a very short period or can last until the next broadcast.
[006 1] [2-2] Network based solution
A network can provide information. For this purpose, the network can use the
location information received from the UE (the requesting UE L01), and the location
information can be protected by the existing network security mechanism.
[0062] [2-3] Device service level information based solution
The requesting UE L01 can use location information provided by a social network or
other services. Security can be ensured in an application layer.
[0063] Detailed examples of the discovery will be explained. The UE 100 can set features
and/or capabilities of Discovery /Discoverable in D2D (device-to-device commu
nication) server.
Case 1A:
If the UE 100 does not know whether the other UEs are in proximity, the UE 100 can
request the ProSe server for the ProSe service, and the ProSe server can send out the
request for the ProSe service and meanwhile get the other UEs location information.
Case 2A:
If the UE 100 can see who is in proximity from e.g. a social network application, and
asks for service, the ProSe server needs to perform the authorization but does not have
to perform Discovery.
[0064] If the ProSe server performs the authorization, the UEs 100 enable the ProSe and/or
UEs 100 to be allowed to get given service/communication means.
[0065] If the discovery is done based on the proximity of UEs 100, the UE 100 sends
location information periodically protected by a unicast security context. The network
200 requests location information when needed or periodically. The request (step 3)
can be broadcasted, and the broadcasted message requires security. The response (step
4) can be protected by the unicast security context.
[0066] The Network stores the conditions for proximity, which can also be given by the re
questing and receiving UE. The network 200 can broadcast to the receiving UEs in a
neighborhood which are allowed to be discovered, and the UEs respond with protected
messages. The UE 100 informs the network 200 of its conditions and capabilities at a
first communication and/or registration or when any change happens.
[0067] The broadcast based solutions by the network 200 or the UE 100 require one or more
of the following requirements. That is, the receiving side should be able to verify the
source, the broadcast message should not be re-used, the network 200 which receives
the response should be able to verify it, or the response should be discarded if it is too
long. The UE 100 can use one or more of solutions for performing secure discovery.
The solutions include a token, a sign, a message, a message ID, a random value, keys,
and stamps. Note that those solutions can be used in the step 5 (mutually authenticate,
the authentication L4), in the step 6 (authorize, the authorization L5), and in the step 7
(generate keys and negotiate algorithm, the secure communication L7), as shown in
Fig. 4. The steps 5 to 7 can happen together, and might be related to broadcast security.
[0068] [3] Initial Authorization (L3)
The initial authorization varies according to the above discovery solution.
[0069] [3-1] Broadcast based:
Whether the requesting UE L01 is allowed to communicate with the receiving UE
L03 can be checked by a network or by the receiving UE L03 having a proof provided
by the network.
[0070] [3-2] Network based:
The requesting UE L01 and the receiving UE L03 can perform a mutual authen
tication over the direct wireless interface.
[0071] [3-3] Device service level information based:
The receiving UE L03 checks a list maintained by the user or in a UE among the
members of the group of devices for ProSe service purpose.
[0072] [4] Authentication (L4)
Once the requesting UE L01 is identified as belonging to the same group, then au
thentication takes place. Authentication can be carried out locally or by interacting
with the network.
[0073] [4- 1] Authentication of the requesting UE L0 1:
This can be performed by successful identification of the requesting UE LOl by a
network or a UE with a proof from a network.
[0074] [4-2] Authentication of the receiving UE L03:
This can be performed by
[4-2-i] using a key shared between the requesting UE LOl and the receiving UE L03
[4-2-ii] using current network security keys or new keys
[4-2-iii] a network which informs the requesting UE LOl of the incoming authen
tication request from the receiving UE L03.
[0075] [5]Authorization - service access control (L5)
There should be different levels for access control to services that the requesting UE
LOl and the receiving UE L03 (hereinafter also referred to as "UE") can use within the
group.
[5-l]UE is allowed to receive and/or send a broadcasting message.
[5-2]UE is allowed to receive and/or send multiple messages.
[5-3]UE is allowed to receive and/or send a message for one-to-one communications.
[5-4] UE authorization according to subscription information and the policy UE set
for ProSe service.
[0076] A network can set up and provide the policy to the group members including the r e
questing UE LOl and the receiving UE L03 according to UE capabilities and user sub
scriptions.
[0077] The network 200 performs authorization for the UEs 100 want to join the group. The
group member of UEs 100 verify whether other UEs are authorized by the network by
using the session keys. Another method for performing validated authorization is done
by (1) a network sending an authorization value to each UE 100, and each UE 100 uses
this value to perform authorization on each other, or (2) Yet another method for
performing a validated authorization is done by sending an authorization value from a
requesting UE to a receiving UE, and then the receiving UE requests the Network to
validate this authorization value and receiving result.
[0078] [6] New key hierarchy and key management (L6)
A new key hierarchy is presented in this exemplary embodiment of the invention.
Key Kp is a key related to the group and also may related to a ProSe service. It has an
indicator KSI_p related to it. Kp can be sent from ProSe Server to use.
[0079] Keys, Kpc and Kpi are session keys that are derived from Kp at UEs. Kpc is a confi
dentiality key and Kpi is an integrity protection key. The session keys are used for UE
to perform authorization for each other, and ProSe communication setup, and have the
direct communication between them.
[0080] After authorization and authentication, the communicating devices including the requesting
UE L01 and the receiving UE L03 can start sessions to communicate with
each other. When the requesting UE L01 and the receiving UE L03 communicate with
each other, they should share communication keys. The keys can be a group key, and/
or a unique key per communicating device as well as a session key per each session.
[0081] The key can be managed by the network and sent over the secure communication
channel with the network. Alternatively, the key can be managed by the requesting UE
L01 and sent to other devices including the receiving UE L03 in the communication,
over a secure unicast communication channel that can be secured by the network
during authentication or verification. The key can also be issued by a third trusted
party.
[0082] The UEs 100 authenticate each other at the beginning of a session (S5). The authen
tication is linked to authorization (S6). Figs. 5A to 5C are schematic views showing
One-to-one, One-to-many, and Many-to-many sessions, respectively. As shown in
Figs. 5A to 5C, a UEa 2 1 and a UEa 3 1 indicate the requesting UE L01, and a UEb 22,
a UEb 32, a UEc 33 and a UEn_33n indicate the receiving UE L03.
[0083] When the session is started, firstly session keys are generated. In this exemplary em
bodiment, the requesting UE L01 (UEa 21, the UEa 31) and the receiving UE L03
(UEb 22, the UEb 32, the UEc 33, the UEn_33n) use two kinds of keys including
session keys.
Case IB:
Each group has a key Kp for each service (Kp is served as a service key) and a new
session key is created for each session.
Case 2B:
Each group has the key Kp (Kp is served as a group key), and a new session key is
created for each session.
[0084] In each case, either the ProSe server or the requesting UE L01 sends keys. For
example, the ProSe server sends the key Kp to the requesting UE L01 and the
receiving UE(s) L03, and the requesting UE L01 sends a session key to the receiving
UE(s) L03 every session. Alternatively, the ProSe server sends both of the key Kp and
the session key to the requesting UE L0 and the receiving UE(s) L03, or the requesting
UE L01 sends both of the key Kp and the session key to the receiving UE(s) L03.
[0085] Further, when the group changes if someone leaves or is added, when a session ends
or a key times out, or when the ProSe server has made a decision, for example, the key
Kp and/or the session key should be changed.
[0086] If the ProSe Server allocates the key Kp to UEs, UEs derive session keys from that
for authorization and communication. UEs can be pre-configured with algorithms for
key derivation, or the key Kp is related to a KSI (key set identifier) and a service.
Because of them, the security problems during UEs' authentication and authorization or
the security problems of a key for direct communication may be solved.
[0087] Note that the key set identifier (KSI) is a number which is associated with the cipher
and integrity keys derived during the authentication. The key set identifier can be
allocated by the network and sent with the authentication request message to the
mobile station where it is stored together with a calculated cipher key CK and an
integrity key IK. The purpose of the key set identifier is to make it possible for the
network to identify the cipher key CK and integrity key IK which are stored in the
mobile station without invoking the authentication procedure. This is used to allow r e
use of the cipher key CK and integrity key IK during subsequent connections (session).
[0088] [7] Secure Communication (L7)
Secure communication can provide message transmission availability between group
member UEs, as well as preventing a message from being eavesdropped on or altered
by UEs that do not belong to the group. Also the secure communication can prevent
UE from using an unauthorized service.
[0089] The communication within the group should have integrity and/or confidentiality
protection. All the communications can be protected by the session keys described
above, after the security association is established.
[0090] The security policy can be a negotiation and an agreement within the group with or
without the support of the operator network L02. All the group members should follow
the security policy.
[0091] Next, the security in the case where UEs' location change happens will be explained.
If none of UEs has a location change, there is no security issue. Further, if all of the
UEs have a changed location, but stayed in proximity to each other, then there is still
no security issue.
[0092] If a part of UEs (one or more UEs) have moved out of proximity from other UEs and
they do not use the ProSe service, group and security management need to be updated
for the remaining UEs in the group. Alternatively, if one or more UEs have moved out
of proximity from the UEs and they want to keep the ProSe service with each other,
group and security management need to be updated for the remaining UEs in the
group, and a new group and security are needed for the traveler.
[0093] Note that the ProSe Server should get UE location information from GMLC
(Gateway Mobile Location Center) periodically, to compare and compute the location
differences of all UEs.
[0094] [8] Termination (L8)
When the communication is to be suspended, devices should remove the session key
while keeping information of the authentication and authorization.
[0095] When the communication is to be terminated, the devices can keep history in
formation, or the allocated token with a lifetime for the next use time to prevent
signaling for authentication and authorization again.
[0096] Smooth handover from an infrastructure to a direct mode will require creation of a
key between communicating parties (the requesting UE LOl and the receiving UE L03)
before a handover happens. For example, if communicating parties are using WiFi, a
key should be allocated to WiFi AP and UEs. The WiFi AP and UEs should authorize
and authenticate each other. The key should have a limited life-time. A network can
recognize which WiFi AP the UE can communicate with. UEs can find that there is a
WiFi AP nearby and the network verifies the WiFi AP. UEs authenticate with the
ProSe Server when UEs connect to a WiFi AP. One option is that the ProSe Function
can allocate keys for the UEs to communicate with a ProSe APP Server.
[0097] To summarize the above description, the method of making a secure communication
of an exemplary embodiment includes the following features:
(1) The operator network L02 determines whether the requesting UE LOl can com
municate with the receiving UE L03 requested by the requesting UE LOl.
(2) Security in discovery of UEs in proximity can be provided by using a token, a
key, and signing provided by the network.
(3) Security in discovery of UEs in proximity can be provided by using a location
provided by the operator network L02.
(4) Security in discovery of UEs in proximity can be provided by using location in
formation provided by social network services, with security provided in an application
layer.
(5) Authorization of the devices can be performed by the network or by devices
direct verification.
(6) Mutual authentication between the requesting UE LOl and the receiving UEs that
agreed to be in the group L03 can be carried out by the network and also both UEs can
be informed with the result.
(7) Mutual authentication between the requesting UE LOl and the receiving UEs L03
can be carried out by both ends with a key shared there between.
(8) New keys for securing the ProSe communication which are a group key and a
unique session key can be used.
(9) Security policy in a group for secure communication is negotiated and set.
(10) Termination management can be performed to prevent the same keys from being
used and set up a security context for other communication.
[0098] According to the secure system of an exemplary embodiment, the operator network
L02 can determine the receiving UE(s) L03 with which the requesting UE LOl can
communicate, and can ensure secure discovery by either providing security parameters
to the requesting UE LOl or receiving UE L03, and providing location information of
the receiving UE L03 to the requesting UE LOl. Furthermore, the operator network
L02 can perform authentication and authorization for the requesting UE L01 and
receiving UE L03, and can support security association between UEs to secure ProSe
communication.
[0099] This software can be stored in various types of non-transitory computer readable
media and thereby supplied to computers. The non-transitory computer readable media
includes various types of tangible storage media. Examples of the non-transitory
computer readable media include a magnetic recording medium (such as a flexible
disk, a magnetic tape, and a hard disk drive), a magneto-optic recording medium (such
as a magneto-optic disk), a CD-ROM (Read Only Memory), a CD-R, and a CD-R/W,
and a semiconductor memory (such as a mask ROM, a PROM (Programmable ROM),
an EPROM (Erasable PROM), a flash ROM, and a RAM (Random Access Memory)).
Further, the program can be supplied to computers by using various types of transitory
computer readable media. Examples of the transitory computer readable media include
an electrical signal, an optical signal, and an electromagnetic wave. The transitory
computer readable media can be used to supply programs to computer through a wire
communication path such as an electrical wire and an optical fiber, or wireless commu
nication path.
[0100] This application is based upon and claims the benefit of priority from Japanese Patent
Application No. 2013137290, filed on June 28, 2013, the disclosure of which is in
corporated herein in its entirety by reference.
Reference Signs List
[0101] 1 secure system
10 system
1 1 UE
12 UE
13 E-UTERN
14 EPC
15 ProSe Function
16 ProSe APP Server
17 ProSe APP
18 ProSe APP
19 eNB
20 eNB
2 1 UEa
22 UEb
3 1 UEa
32 UEb
33 UEc
33n UEn
100 UE
100a system
100b system
200 network
L01 requesting UE
L02 operator network
L03 receiving UE
LI secure group management
L2 secure discovery
L3 initial authorization
L4 authentication
L5 authorization
L6 security association establishment
L7 secure communication
L8 termination

Claims
[Claim 1] A secure system including a plurality of User Equipments (UEs),
comprising:
a requesting device which requests a communication; and
a receiving device which receives a communication request from the
requesting device,
wherein the requesting device and the receiving device are members of
a specific group or potential members which join the specific group
when the requesting device discovers the receiving device, and
wherein the requesting device and the receiving device satisfy one or
more requirements for security, the requirements for the security
including a first requirement that the requesting device is authorized by
a network to discover receiving devices that are in the specific group or
to form the specific group, a second requirement that the requesting
device and the receiving device in the specific group are able to
perform a mutual authentication over a direct interface, and to perform
authorization with a proof provided by a network, and a third re
quirement that the requesting and receiving device are able to secure
the direct communication.
[Claim 2] A method of making a secure communication provided by a secure
system including a requesting device which requests a communication,
and a receiving device which receives the communication request from
the requesting device, a method comprising:
joining a specific group before or after the requesting device discovers
the receiving device; and
satisfying one or more requirements for security, the requirements for
the security including a first requirement that the requesting device is
authorized by a network to discover receiving devices that in the
specific group or to form the specific group, a second requirement that
the requesting device and the receiving device in the specific group are
able to perform a mutual authentication over a direct interface, and to
perform authorization with a proof provided by a network, and a third
requirement that the requesting and receiving device are able to secure
the direct communication.
[Claim 3] The method of making a secure communication according to claim 2,
further comprising:
performing authentications locally or by using the network, once the reWO
2014/208032 PCT/JP2014/003154
questing device and the receiving device are authorized as belonging to
the same specific group.
[Claim 4] The method of making a secure communication according to claim 3,
wherein
authentication of the requesting device is performed by the network or
by the receiving device verifying a proof that the network provided to
the requesting device, and
authentication of the receiving device is performed by one or more
ways, the ways including a first way that uses a key shared between the
requesting device and the receiving device, the second way that uses
current network security keys or new keys, and that the network can
inform a requesting device of successful authentication result of the
receiving device.
[Claim 5] The method of making a secure communication according to any one of
claims 2 to 4, further comprising:
performing one or more authorizations of different levels for access
control to services, the services being used by communication devices
including the requesting device and the receiving device within the
specific group,
wherein the authorizations include a first authorization that the commu
nication devices are allowed to receive and/or send a broadcasting
message, a second authorization that the communication devices are
allowed to receive and/or send multiple messages, and a third autho
rization that the communication devices are allowed to receive and/or
send a message for one-to-one communications.
[Claim 6] The method of making a secure communication according to any one of
claims 2 to 5, further comprising:
setting up and providing a security policy by the network to the
members of the specific group according to UE capabilities and user
subscriptions.
[Claim 7] The method of making a secure communication according to claim 3,
wherein
the network sends a key Kp to the requesting and receiving devices so
that the requesting and receiving devices can derive session keys for
authorization and secure communication with each other.
[Claim 8] The method of making a secure communication according to any one of
claims 3, 4, 5 and 7, further comprising:
sharing communication keys by communication devices including the
WO 2014/208032 PCT/JP2014/003154
requesting device and the receiving device after the authorizations and
the authentications, the communication keys including confidentiality
and integrity protection session keys for each session,; and
establishing a communication between the communication devices
using the communication keys.
[Claim 9] The method of making a secure communication according to claim 8,
wherein
the communication keys are managed by the network and sent over a
secure communication channel with the network and/or are managed by
the requesting device and sent to other communication devices over a
secure unicast communication channel that is secured by the network
during the authorizations and the authentications, or derived at the
devices from a key Kp.
[Claim 10] The method of making a secure communication according to any one of
claims 7 to 9, wherein
the communication between the communication devices is established
with a secure communication, the secure communication providing
message transmission availability between the members of the specific
group and/or preventing the message from being eavesdropped on or
altered by UEs that do not belong to the specific group.
[Claim 11] The method of making a secure communication according to any one of
claims 2 to 10, further comprising:
setting up a security policy of the specific group; and
agreeing to and following the security policy by all of the members of
the specific group.
[Claim 12] The method of making a secure communication according to any one of
claims 8 to 10, further comprising:
removing the session key while keeping information of the authen
tications and/or the authorizations when the communication is to be
suspended.
[Claim 13] The method of making a secure communication according to any one of
claims 8 to 10 and 12, further comprising:
keeping information for use in the authentication and/or the autho
rizations by the communication devices when the communication is to
be terminated.