Prepayment Standard Transfer Specification: An IEC standard
Especificação de Transferência de Padrões de Pré Pagamento: Um padrão IEC
Don Taylor
Prepayment Standard Transfer Specification: An IEC standard
Don Taylor, STS Association, South Africa
The Standard Transfer Specification is a secure message protocol between a POS and
a Meter, supported by a secure Key Management System and protocol. The STS has
been an industry standard since 1994 and is now also published as IEC/PAS 62055­
41. It is currently being converted into a full IEC standard and publication is targeted
for 1 st half of 2006. There are approximately 5 million STS meters installed in about 30
countries and operated by about 300 utility companies. This entire user base is served
from one Key Management Center with about 700 Supply Group keys under its
management care.
The STS Association is the custodian of the STS and continues to sustain the standard
in all its phases from development to application and maintenance. It also assures the
integrity and quality of the support infrastructure and facilitates access to services like
key management, product certification and the further development of standards.
Members currently comprise of 18 manufacturers, 2 utility companies and one
AMEU/ESLC representative.
Activities of the STS Association are focusing on facilitation of key management
services, product certification services, certification of other key management systems
and codes of practice for key management centers. It is actively participating on WG15
of IEC TC13 towards creation of the full IEC standard, developing enhancements to the
STS and to the existing key management system.
IEC standards that are relevant to prepayment meters, which are already published or
in final stage of publication are IEC 62051 (Glossary of terms), IEC 62052­11: General
requirements for metrology, IEC 62053­21: Particular requirements for metrology, IEC
62055­21: Framework for standardization, IEC 62055­31: Particular requirements for
payment meters and IEC 62055­41: Standard Transfer Specification.
The IEC 62055­21 Framework looks at the standardization of payment metering
systems and covers processes, functions, data elements, system entities and
interfaces from a generic perspective. It further advocates a scheme whereby many
systems or subsystems may be standardized within the IEC 62055 set of standards,
such as the STS, which is thus the first one in the set to be standardized in this
fashion. Generic functions and processes with sub­classification of functions for a
single part payment meter are also detailed.
The IEC 62055­41 Standard Transfer Specification uses the OSI reference model
defining at least an application layer and physical layer protocol with the token carrier
as the medium in the physical layer. This makes the standard more versatile and
manageable. It also defines the generic structure for a Virtual Meter in terms of
Function Objects, which in turn describe the functionality of the payment meter and,
which are then specifically defined in Companion Standards under the management of
the STS Association.
Enhancements to the STS, currently under development, follow the same IEC
reference model and maintain backward compatibility with the present STS version.
Main features of the enhancements are: bulk data transfer token; token frame with up
to 255 tokens in one frame; feedback data from the meter via the token carrier; 2 way
token carrier; 21 digit numeric token; The Companion Standards currently under
consideration are: step tariff with auxiliary charges; accounting function with social
credit, token credit, credit advance and lifeline credit; metering for water; control valve
for water; real­time clock with battery;
Requirements for key management enhancements under consideration are: the key
management center should be globally trusted, industry impartial and cater for the
deregulated market; services should be automated on 24/7 basis and remotely
accessible; variety of secure module formats, remote coding and inter ­ KMC key
exchange protocol.
In conclusion it would be true to say that prepayment is still growing and developing
and establishing support infrastructure in the international arena, while maintaining
healthy standards.
Standard Transfer Specification:
an
IEC Standard
Don Taylor
chairperson
STS Association ­ South Africa
www.sts
.org.za
za
www.sts.org.
STS ?
•
•
•
•
•
•
•
•
Payment
Credit
Encryption
Token
Decryption
Credit
Consumption
Key
Management
Point Of Sale
Credit
Payment
Encrypt
Key
Key
Management
System
Token
Key
Consumer
Decrypt
Credit
Supply
M
Prepayment Meter
Consumption
STS ?
•
•
•
•
•
•
•
•
Standard Transfer Specification
Secure message protocol ­ POS / Meter
Secure key management system + protocol
IEC standard
5 million meters
30 countries
300 utilities
1 Key Management Center ­ South Africa
700 SGC keys
STS Association ?
• Custodian of the STS
• Facilitates the support infrastructure
• Key Management, Certification and Standards
• 21 members
• 19 manufacturers + 2 utilities + AMEU/ESLC
STSA focus ?
•
•
•
•
•
•
•
Key management services
Certification of products
Certification of key management systems
Codes of practice for key management
IEC standardization
STS enhancement
Key management enhancement
IEC ­ Payment Meters
• 62051
: Glossary
• 62052­11: General requirements (metrology)
• 62053­21: Particular requirements (metrology)
• 62055­21: Framework for standardization
• 62055­31: Type Specification (payment meter)
• 62055­41: Standard Transfer Specification
IEC ­ Concept model
(62055­
21)
(62055­21)
Processes
use
• General
system
concepts
use
operate
on
Data Elements
Functions
embodied in
embodied in
System Entities
comprises
comprises
Interfaces
Users
Devices
instances
Supplier
Customer
Operator
Installer
Inspector
instance
IEC ­ Framework
Token
Carrier
instance
Interfaces
Payment
Meter
(62055­
21)
(62055­21)
Generic processes
• More than
one
standard
Generic functions
Data Elements
System
1
Customer Information Systems
CIS use
to POS Interfaces
• Create
when
required
Point Of Sale Systems
use Carrier Interfaces
POS to Token
Token Carriers
• STS is 1 st
one of
the set
use to Meter Interfaces
Token Carrier
Payment Meters
System
2
System
n
IEC ­ Meter model
(62055­
21)
(62055­21)
Supply
network
• Single­
part
payment
meter
connected supply
Token
Token
Carrier
Metering
metered supply
• Generic
functions
Token Carrier
Interface
Accounting
Meter
Application
Process
Test
Display
Delivery
User
Interface
Recording
Time
Security
delivered supply
Load circuit
IEC –
Standard Transfer Specification
(62055­41)
• STS tokens
• STA
• DES
• Mag card
• Numeric
• Serial port
POS
Application
Process
METER
Application
Process
Key Management
APDU
APDU
Application Layer
Protocol
Application Layer
Protocol
TCDU
TCDU
Physical Layer
Protocol
Physical Layer
Protocol
Virtual Meter
Function Objects
Token Carrier
Standard Transfer
Specification
Companion
Standards
STS ­ Enhancement
•
•
•
•
•
•
•
Follows IEC model
Backward compatible
Bulk token (40­940 bits)
Token frame (255 tokens)
Feedback from meter
2 way token carrier (Dallas iButton, Smart card)
Companion standards
Companion Standards
•
•
•
•
•
•
•
•
•
•
Step tariff
Auxiliary charge
Social credit
Token credit
Credit advance
Lifeline credit
Metering (water meter)
Delivery (water valve)
Real­time clock
Battery backup
Key Management enhancement
• Requirements
•
•
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•
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•
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Globally trusted Key Management Center
Industry impartial Key Management Center
Deregulated market needs
Distributed services architecture
Automated services 24/7
Remote Secure Module coding
Variety of Secure Module formats
Inter – KMC protocol
Standards repository
STSA ­ STS ­ IEC
• International arena
• Creating support infrastructure
• Providing services
Finally ?
• Article in Metering International
• Visit our website : www.sts
.org.za
za
www.sts.org.
• Join the STS Association
• Come speak to me
Biography
Speaker:
Don Taylor
Position:
Chairman
Company: STS Association
Country:
South Africa
Don Taylor is the Director of Technology for Actaris Measurement & Systems (Pty) Ltd. He is
currently Chairman of the STS Association and a participating working group member on
various standards organisations such as the SANC for the IEC, SANS, NRS, STS Association
and IEC. He is also a longstanding member of the SAIMC.
In 1976 he graduated with a Higher National Diploma in Electrical Engineering from the Cape
College for Advanced Technical Education, after which he worked for 2 years in the gold
mining industry followed by 10 years for the CSIR and 18 years in the prepayment industry.
He is recognized as a co­founder of the prepayment industry in SA and developer of the first
commercialized solid­state integrated prepayment meter worldwide in 1985. He also co­
founded the first South African prepayment meter manufacturing company Angcon
Technologies in 1986, which later became AEG Energy Control, then Schlumberger and now
Actaris. In 1994 he co­founded the IEC WG15 for payment systems and in 1997 co­founded
the STS Association of which he has been chairman since 2000.
Company Background Information
Company:
STS Association
Country:
South Africa
The STS Association ensures that users of the Standard Transfer Specification have the
supporting infrastructure to enable the secure operation of prepayment systems, and assures
the interoperability of equipment from different suppliers through the certification of STS
compliant equipment. The Association promotes the application of the standard, and further
develops it to meet emerging international needs for additional functionality.