1. TETRA Experience 2006
Sao Paulo
July 18th 2006

2. TETRA Security Encryption and Management
Ramón Montañez

3. 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

4. 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

5. 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

6. TETRA Experience - Brazil
Network Security
IT security is vital in TETRA networks
Gateways are particularly vulnerable.
Operating staff need vetting
Firewalls required at access points to the network
July 18-19, 2006
TETRA Experience - Brazil

7. 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. Authentication
2. Air Interface Encryption
3. End - to
End Encryption
XYZ”
July 18-19, 2006
TETRA Experience - Brazil

8. 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

9. TETRA Experience - Brazil
Authentication
Authentication Center
Challenge
Session keys
Calculated Response
Switch
Secret keys
Mutual Challenge MS
Calculated Response
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!
July 18-19, 2006
TETRA Experience - Brazil

10. 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
SCK, GCK etc…
Standardized format
Imports key material from any vendor
AuC
TEI
Factory
TEI
TETRA
SwMI
Key Programming K
K, TEI
July 18-19, 2006
TETRA Experience - Brazil

11. 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

12. The purpose of Air Interface Encryption
Network fixed links are considered difficult to intercept.
Clear
Air
Interface!
The air interface was considered vulnerable.
Air Interface encryption was designed to make the air interface comparably as secure as the fixed line connection
Air
Interface
Encryption
Fixed
Links
Operational
Information
July 18-19, 2006
TETRA Experience - Brazil

13. 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

14. 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

15. 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

16. End to end encryption in TETRA
ETSI Project TETRA provides standardized support for end to end Encryption
ETSI EN 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

17. 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

18. 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

19. 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

20. 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
Link
Other
Network
Other
Network
TETRA
Network
Other
Network
Landline
July 18-19, 2006
TETRA Experience - Brazil

21. 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

22. 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

23. 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

24. 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

25. 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

26. 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

27. What security level do you want?
TETRA Class 1
TETRA Class 2
TETRA Class 3
TETRA w/ E2E algorithm on Smart Card
TETRA w/ E2E SW algorithm in radio
TETRA w/ E2E hardware solution
TETRA your Service
July 18-19, 2006
TETRA Experience - Brazil

28. TETRA Experience - Brazil
Thank You
July 18-19, 2006
TETRA Experience - Brazil 18

29. TETRA Experience 2006
Sao Paulo
July 18th 2006

30. TETRA Data Services & Applications
Ole Arrhenius
TETRA Experience Sao Paulo,

31. Contents Basic data services in TETRA The concern about data speed
TETRA data applications, examples
Wireless Application Protocol, WAP
Towards higher data speeds
Conclusions

32. Basic data services in TETRA
4 channels
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 1 2
36 kbits/s
gross bit
rate 3 4
Carrier

33. 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

34. Short Data Service
Four 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
Hello, I will be back in the ioffice in 15 minutes. I will call you then. John OK
MM05 11:28 p12553: VIPs arriving in 5 minutes at gate 23, prepare security and transport. OK

35. IP-packet data Similar to the GPRS service in GSM networks
Enables advanced data applications
Enables Intranet and Internet connectivity
Excellent application platform
Uses traffic channel, single slot or multiple time slots

36. TETRA data services enable a wide range of applications
Database access
Image communications
Intranet/internet access
Reporting
, calendar
Workforce management
CC&C system integration
File transmission
Information push, alarm distribution
Information pull
Control and monitoring, telemetry

37. TETRA fullfils 95% of daily data needs
Fundamental daily services 95%
TETRA
GPRS
EDGE 3G
Data speed
< 28 kbps
< 40kbps
< 160kbps
< 1Mbps
Multimedia services
Text, images
Text, images, video
Internet/intranet access
Yes
Complementing non-critical services 5%
Complementary wireless data services can be used to complement non-critical data services, if necessary

38. 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

39. The concern of data speed, example
Optimized for handportable radio’s screen 7 kB
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

40. 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

41. On screen AVL map with touch screen action buttons …

42. ZOOM + ZOOM -- F9 MOB F1 Show F2 Report/His F3 Status F4 Maps/AVL
F5 Messages F6
Equipment
F7 Forms/En
POKE/K1
F8 Setup
812
Free
On the way
813
At scene
Transport
ZOOM +
Not in car
811
ZOOM --
Car chase
814
Off-duty
F9 MOB

43. 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

44. More examples of applications using TETRA data services

45. 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

46. 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

47. 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
WAP Server
Application Portal
2. Locate
3. Mail
4. Report
5. Search
Link
Menu
TETRA

48. What about the future ?

49. 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

50. Development continues
Next …
TETRA High Speed Data
Evolution
Java
Multi-slot packet data
Situation awareness
Integrated GPS
Colours
Advanced location applications
Image communication
Time

51. 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

52. TETRA Experience 2006
Sao Paulo
July 18th 2006