TETRA Experience 2006 Sao Paulo July 18 th 2006
Jan 02, 2016
July 18-19, 2006 TETRA Experience - Brazil
Agenda
Security threats TETRA security features Authentication Air interface Encryption End to End encryption Practical security measures
July 18-19, 2006 TETRA Experience - Brazil
What we want to achieve with Security
Confidentiality– No one can eavesdrop on what we are saying
Integrity– The information gets there completely intact
Availability– Communications are possible where and when
they are needed Authenticity
– The people we are talking to are the right people– The wrong people can’t try and join us
July 18-19, 2006 TETRA Experience - Brazil
Threats to communication and the threats to security
Message related threats– interception, eavesdropping, masquerading, replay,
manipulation of data
User related threats– traffic analysis, observability of user behavior
System related threats– denial of service, jamming, unauthorized use of resources
July 18-19, 2006 TETRA Experience - Brazil
Network Security
IT security is vital in TETRA networks Gateways are particularly vulnerable.Operating staff need vettingFirewalls required at access points to the network
July 18-19, 2006 TETRA Experience - Brazil
Key Definitions of TETRA Security– Authentication - ensures only valid subscriber units have
access to the system and subscribers will only try and access the authorized system
– Air Interface Encryption – protects all signaling, identity and traffic across the radio link
– End-to-End Encryption protects information as it passes through the system
Base Station Infrastructure
Dispatcher
“????”“????”
1. Authentication1. Authentication
2. Air Interface Encryption2. Air Interface Encryption
3. End3. End--toto--End EncryptionEnd Encryption
“XYZ”
Base Station
July 18-19, 2006 TETRA Experience - Brazil
Authentication
Used to ensure that terminal is genuine and
allowed on network.
Mutual authentication ensures that in addition to
verifying the terminal, the SwMI can be trusted.
Authentication requires both SwMI and terminal
have proof of secret key.
Successful authentication permits further security
related functions to be downloaded.
July 18-19, 2006 TETRA Experience - Brazil
Authentication
Authentication provides proof identity of all radios attempting use of the network
Radio can authenticate the network in turn, protects against ‘fake base stations’ etc
A session key system from a central authentication centre allows highly secure key storage – Secret key need never be exposed
Authentication process derives air interface key (TETRA standard) – automatic key changing!
MS
Switch
Session keysChallenge
Authentication Center
Mutual Challenge
Calculated Response
Calculated Response
Secret keys
July 18-19, 2006 TETRA Experience - Brazil
Radio Security Provisioning And Key Storage
TETRA MoU SFPG Recommendation 01 provides a standardized format for importing authentication and other air interface encryption keys
Use of Recommendation 01 files will allow multi vendor terminal supply
Separation of logical key programming step from factory can allow all keys to be loaded in country
– Meets national security requirements
Factory
Key Programming
TEI
TEI
K K, TEI
AuCStandardized formatImports key material from any vendor
TETRASwMI
SCK, GCK etc…
July 18-19, 2006 TETRA Experience - Brazil
What is Air Interface Encryption? First level encryption used to protect information over the Air
Interface– Typically software implementation– Protects almost everything – speech, data, signaling, identities…
Class Encryption OTAR Authentication 1 No No Optional 2 Static key Optional Optional
3 Dynamic key Mandatory Mandatory
July 18-19, 2006 TETRA Experience - Brazil
The purpose of Air Interface Encryption
OperationalInformation
ClearClearAirAir
Interface!Interface!
The air interface was considered vulnerable.
Network fixed links are considered difficult to intercept.
Air Interface encryption was designed to make the air interface comparably as secure as the fixed line connection
July 18-19, 2006 TETRA Experience - Brazil
Air Interface traffic keys
Four traffic keys are used in class 3 systems:- Derived cipher Key (DCK)
– derived from authentication process used for protecting uplink, one to one calls
Common Cipher Key (CCK)– protects downlink group calls and ITSI on initial registration
Group Cipher Key (GCK)– Provides crypto separation, combined with CCK
Static Cipher Key (SCK)– Used for protecting DMO and TMO fallback mode
July 18-19, 2006 TETRA Experience - Brazil
Standard air interface algorithms
TEA1 and TEA4– General use including public safety
TEA2– Europe public safety and military organizations only.
TEA3– For use by public safety and military organizations
outside of Europe.
July 18-19, 2006 TETRA Experience - Brazil
Over The Air Re-keying (OTAR)
Populations of terminals tend to be large and spread over wide areas so the only practical way to change encryption keys is by OTAR
This is done securely by using a derived cipher key or a session key to wrap the downloaded key
The security functionality is transparent to the user as the network provider would normally be responsible for OTAR and management of AI keys
July 18-19, 2006 TETRA Experience - Brazil
End to end encryption in TETRA ETSI Project TETRA provides standardized support for end to end
Encryption – ETSI EN302109 contains specific end to end specification– Ensures TETRA provides a standard alternative to proprietary offerings
and technologies– Ensures compatibility between infrastructures and terminals
Many organizations want their own algorithm– Confidence in strength– Better control over distribution
TETRA MoU – Security and fraud Protection Group (SFPG)– Provides detailed recommendation on how to implement end to end
encryption in TETRA
The result – Standardization and compatibility, with choice of algorithm
– A big strength of TETRA
July 18-19, 2006 TETRA Experience - Brazil
Standard end to end encryption algorithms
There are no ‘standard’ algorithms defined by SFPG but: IDEA was defined as a good candidate 64 bit block cipher
algorithm for use with TETRA and test data and an example implementation was produced
AES128 (Rijndael) was defined as a good candidate 128 bit block cipher algorithm for use with TETRA and test data and an example implementation was produced
Both algorithms have proved popular with public safety organizations and give a good level of security assurance to sensitive data
July 18-19, 2006 TETRA Experience - Brazil
End To End Encryption ‘Standardization’
TETRA MoU SFPG Recommendation 02– Framework for end to end encryption– Recommended synchronization method for speech calls– Protocol for Over The Air Keying– Sample implementations including algorithm mode and key
encryption– DOES NOT specify implementation – can be implemented
with module, software, SIM card etc..– DOES NOT provide module interface specification
July 18-19, 2006 TETRA Experience - Brazil
Related Recommendations TETRA MoU SFPG Recommendation 01
– Key transfer specification– Currently being updated to include end to end encryption
key import formats TETRA MoU SFPG Recommendation 07
– Short data service encryption TETRA MoU SFPG Recommendation 08
– Framework for dividing encryption functionality between a SIM (smartcard) and a radio
– No defined bit level interface (export control issue) TETRA MoU SFPG Recommendation 11
– IP Packet data encryption– Work in process– Will provide a suitable means for high security packet data encryption, with
commonality with voice encryption
July 18-19, 2006 TETRA Experience - Brazil
Implementing TETRA security TETRA security measures are by no means the complete
picture How well they are implemented – and how the
implementation is evaluated is critical The rest of the network – what else connects to TETRA –
is equally important The operational process and procedures equally provide
countermeasures to the threats
Landline
TETRANetwork
OtherNetwor
k OtherNetwor
k OtherNetwor
k
Link
July 18-19, 2006 TETRA Experience - Brazil
Implementation considerations – Air Interface Encryption
AIE should provide security equivalent to the fixed network There are several issues of trust here
– Do I trust that the AIE has been implemented properly?– Does AIE always operate (during registration, in fallback modes
etc)?– Do I trust the way that the network (or radio) stores keys?– Do I trust the fixed network itself or can someone break in?
A strong AIE implementation and an evaluated network can provide essential protection of information
An untested implementation and network may need reinforcing, for example with end to end encryption
July 18-19, 2006 TETRA Experience - Brazil
Benefits of end to end encryption in combination with Air Interface encryption
Air interface (AI) encryption alone and end to end encryption alone both have their limitations
For most users AI security measures are completely adequate Where either the network is untrusted, or the data is extremely
sensitive then end to end encryption may be used in addition as a overlay.
Brings the benefit of encrypting addresses and signalling as well as user data across the Air Interface and confidentiality right across the network
July 18-19, 2006 TETRA Experience - Brazil
Disabling of terminals
Vital to ensure the reduction of risk of threats to system by stolen and lost terminals
Relies on the integrity of the users to report losses quickly and accurately.
Disabling may be either temporary or permanent Disabling stops the terminal working as a radio and:
– Permanent disabling removes all keys including (k)
– Temporary disabling removes all traffic keys but allows ambience listening
The network or application must be able to remember disable commands to terminals that are not live on the network at the time of the original command being sent.
July 18-19, 2006 TETRA Experience - Brazil
Useful Recommendations
TETRA MoU SFPG Recommendation 03 – TETRA threat analysis– Gives an idea of possible threats and countermeasures
against a radio system TETRA MoU SFPG Recommendation 04 – Implementing
TETRA security features– Provides guidance on how to design and configure a TETRA
system Both documents are restricted access requiring Non
Disclosure Agreement with SFPG
July 18-19, 2006 TETRA Experience - Brazil
Assuring your security solution There are two important steps in assuring the security of
the solution: Evaluation and Accreditation
Evaluation of solutions should be by a trusted independent body– Technical analysis of design and implementation
Accreditation is the continual assessment of risks – Assessment of threats vs. solutions
• Procedural and technical solutions– Should be undertaken by end user representative and/or
their government national security organization
July 18-19, 2006 TETRA Experience - Brazil
Maximizing cost effectiveness
Evaluation can be extremely expensive – how to get best value for money?
Establish the requirements in advance– as far as they are known – security is always a changing
requirement! Look for suppliers with track record and reputation Look for validations of an equivalent solution elsewhere Consider expert help on
processes and procedures
July 18-19, 2006 TETRA Experience - Brazil
What security level do you want?TETRA Class 1TETRA Class 2TETRA Class 3TETRA w/ E2E algorithm on Smart Card TETRA w/ E2E SW algorithm in radioTETRA w/ E2E hardware solution
TETRA is @ your Service
July 18-19, 2006 TETRA Experience - Brazil
www.Tetramou.comwww.ETSI.org
www.Motorola.com/[email protected]
Thank You
Contents
Basic data services in TETRA
The concern about data speed
TETRA data applications, examples
Wireless Application Protocol, WAP
Towards higher data speeds
Conclusions
Basic data services in TETRA
Status messages– efficient, real time
Short Data Service, SDS– text messaging +
application platform
IP packet data– advanced applications,
opens the world of Intranet and Internet connectivity
Circuit mode data– for specialized applications,
rarely used
36 kbits/sgross bit
rate
4 channels
1 2
3 4
Carrier
Status messages
Data sent as 16 bit numeric values
32768 values free for use, the rest reserved for system use
Converted into text in the receiving terminal or workstation
Fast and efficient
Easy to use
Sent over control channel, do not load traffic channels
Short Data ServiceFour SDS-types specified by TETRA standard:
SDS-1, SDS-2, SDS-3 and SDS-4 TL
SDS-1, -2 and -3 are fixed length (16, 32, 64 bits)
SDS-4 TL is variable length (max 1278 bits). Protocol identifier defines how SDS-4 is used, most typical use is text messaging (140/160 chars) and AVL
Data sent over control channel or traffic channel (simultaneous voice and data)
Text entry using the keypad of the phone, single device for voice and data
MM05 11:28 p12553: VIPs arriving in 5 minutes at gate 23, prepare security and transport.
OK
Hello, I will be back in the ioffice in 15 minutes. I will call you then. John
OK
IP-packet data
Similar to the GPRS service in GSM networks
Enables advanced data applications
Enables Intranet and Internet connectivity
Excellent application platformUses traffic channel, single slot
or multiple time slots
TETRA data services enable a wide range of applications
Database accessImage communicationsIntranet/internet accessReportinge-mail, calendarWorkforce management CC&C system integration File transmissionInformation push, alarm
distributionInformation pull Control and monitoring, telemetry
TETRA fullfils 95% of daily data needs
TETRA GPRS EDGE 3G
Data speed < 28 kbps < 40kbps < 160kbps < 1Mbps
Multimedia services Text, images
Text, images
Text, images, video
Text, images, video
Internet/intranet access Yes Yes Yes Yes
Complementing non-criticalservices 5%
Fundamental daily services 95%
Complementary wireless data services can be used to complement non-critical data services, if necessary
The concern of data speed
Single slot IP packet data provides approximately 3 … 4 kbps payload
Multislot data increases performance but has side effects– Increased power consumption in handsets– Decreases voice capacity
Robust basic data services more important than extreme speeds especially in public safety
Majority of daily data services consist of low data volume database queries in the range of 0.5 … 10 kB per transaction
Smart applications are more important than the raw data speed, bloated applications will eat available bandwidth, no matter how much bandwidth is available
The concern of data speed, example
• Original photo image taken with a digital camera. Original size is 1600x1200 and file size 1MByte
• Pixel size of a TETRA handheld terminal typically 100 x 130 pixels
• Compression and optimization for 100x130 pixel screen shrinks the 1MByte image into 7 kilobytes
100 x 130 x 16 (colour) = 26 kBytes
With further optimisation and compression from 26 kB to 7 kB
Optimized for handportable radio’s screen 7 kB
Example of an integrated, smart application
• Police field command application using AVL, on-board databases, status messaging, text messages and IP packet data
• Minimizes over-the-air data, yet very graphics intensive and informative
813
812
Off-duty
Car chase
Not in car
At scene
Transport
On the way
Free
F9MOB
POKE/K1F1Show
F7Forms/En
F6Equipment
F3Status
F4Maps/AVL
F2Report/His
F8Setup
F5Messages
814
811
ZOOM--
ZOOM+
Send only the necessary information over the air
Keep high volume, ‘static’ data (maps, images, floorplans of buildings) in onboard databases
Update static data at the station using fixed LAN or WLAN
Over the air information is typically low volume:– Location information– Status of field units– Text messaging– Compressed images
Automatic Vehicle/Person Location, AVL / APL
Integrated GPS in new terminals
Position of every unit in real time
– Location shown on GIS at Command and control room
TETRA SDS or TETRA IP can be used to deliver location information
New ETSI LIP standard for compact SDS location information, 76 bits instead of about 200 bits
Image communication
”One picture paints thousand words”
TETRA IP one slot packet data is sufficient for image transmission
Image compression technologies reduce data volumes for fast transmission, e.g. JPEG2000
Retrieve images from a database (pull)
Send images from command and control centre (push)
Increases efficiency and officer safety
Wireless Application Protocol (WAP)
Specified to create a global protocol to work across differing wireless network technologies
WAP offers bearer independence
Allows applications developed to work across TETRA and GSM and GPRS
Optimised for the constraints of handheld devices
Application Portal2. Locate
3. Mail
4. Report
5. Search
Link Menu
WAP Server
TETRA High Speed Data
TETRA high speed data is part of TETRA 2 standardization
TETRA HSD will complement the current TETRA services with higher data speeds
User experience comparable to GPRS/EDGE
Very spectrum-efficient
Adapts its speed (modulation) when necessary
Development continues
Evolution
TETRA High Speed Data
Time
Integrated GPS
Colours
Next …
Imagecommunication
Advanced locationapplications
Java
Situationawareness
Multi-slot packet data
Summary
TETRA provides a rich set of basic and advanced data services
Data applications complement TETRA voice services
IP over TETRA is a solid and robust platform for data applications
Accessing data from the field opens totally new opportunities for public safety and other user segments
Data speed in TETRA IP cover the majority of current needs