Token Identifier rollover
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D-day for when all STS prepayment meters will be affected by the TID rollover scheduled for 24 November 2024 may seem far in the future but the risk of not being prepared is that any token generated after this date and using the 24-bit TID will be rejected by the meter.


This article first appeared in ESI Africa Edition 2, 2019. You can read the magazine's articles here or subscribe here to receive a print copy.

Here is a thorough checklist to ensure your tokens are not deemed as being old as the TID value embedded in the token will have reset back to zero.

The Token Identifier is a 24-bit field, contained in STS compliant tokens, that identifies the date and time of when the token was generated. It is used to determine if a token has already been used in a prepayment meter. The TID represents the number of minutes elapsed since the base date of 1 January 1993.

The incrementing of the 24-bit field means that at some point in time, the TID value will roll over to a zero value. Notably, the TID has a limited range and will run out in November 2024, at which point all existing prepayment meters will stop accepting credit tokens. In order to circumvent this issue, the memory of each meter needs to be cleared of all stored TIDs and its cryptographic key needs to be changed before 2024.

Why has this come about?

With technology constantly changing and upgrading, the STS system had to include positive changes to ensure that the system continues to operate the way it has since its inception. Also, with the concerns and challenges that the market faces in terms of ghost vending – the illegal practice of selling prepaid electricity resulting in a loss of revenue and contributing significantly to nontechnical losses at utilities – a solution needed to be implemented.

Some of the benefits of this process are:

Significantly stronger algorithms for vending key creation and protection. The new system will use up to 192bit encryption and state-of-the-art algorithms.

Key expiration, which will allow for a vending key to be expired after a certain time. This ensures that even if a vending key has been comprised, the key will expire after a stipulated timeframe, significantly reducing the risks when a vending system or security module is stolen.

The longevity of the STS system is guaranteed.

All meters that have used tokens purchased from unauthorised vendors will no longer be able to purchase from those vendors.

Your rollover project management checklist

1. Secure module suppliers: confirm if these are upgradable based on the prism unique serial and process upgrade

  • Upgrade SM to cater for the rollover bit and multiple base dates
  • Test SM by initialisation, keyloading, and new firmware functionality to the STS600-4-2 specification
  • Certify SM to CTS spec for STS600-4-2 (STS531-8-2)
  • Field test SM by code at KMC and test tokens with live keys
  • Deploy upgraded SM to the field

2. Key management centre suppliers: application for new keys with new base dates

  • Issue new vending keys in the new key load file format to upgraded vending and meter manufacturer systems when so requested and are ready to receive them
  • Maintain support for legacy key load files until all TID rollover key change programs have been completed

3. Upgrade vending software: vending system upgraded to support STS600 edition 2

  • Update software to cater for the new Key Load File (9KLF) specification
  • Update software to handle multiple base dates
  • Certify software to CTS test specs
  • Upgrade customer vending software in the field
  • Get contact details of all subvendors that use their vending systems and communicate these to the STS Association

4. Utilities: responsible for their own rollout plan of the TID rollover keychanges to the new base date

  • Request the vending system supplier to upgrade the vending system
  • In the case where the utility has developed its own vending system, the utility must do the upgrade
  • Divide the installed base of meters into smaller manageable groups for processing one group at a time
  • Decide on key-change program option
  • Compile a program for the entire key change operation
  • Start the program on a pilot site to test the processes
  • Roll out to other meter groups
  • Ensure that the entire program is completed at least one year before the TID rollover date of 2024

Challenging areas to be anticipated

The Token Identifier rollover is a segmented process involving different segments of the STS compliant prepayment architectural landscape.

This could offer some level of difficulty or provide challenges if not managed correctly. Sound planning, with active marketing, is key in overcoming the challenges related to:

  • Key management centre for the application of a vending key on a new base date
  • Security module to cater for the rollover functionality
  • Vending system to allow for the management of the change process
  • Meter manufacturing on a new vending key with a new base date
  • Utility planning and marketing of a rollout plan
  • Consumer support centre

Note that the affected stakeholders and utilities need not attempt the rollover in isolation as Landis+Gyr welcomes the opportunity to assist in ensuring the successful execution of this process. The company has invested considerable time and resources into ensuring that Landis+Gyr’s technical departments fully understand the segments within this process, so as to be better equipped to meet and exceed the needs of any utility or party requiring further assistance.

Landis+Gyr are ready and able to provide support relating to:

  • upgrading of secure modules with assistance in understanding the new annual licence fees related to these modules,
  • guidance with and application for new vending keys with new base dates,
  • ensuring that the current used vending software is upgraded and will manage the change process, and
  • actioning the already planned and marketed roll out plan to the meter base.

The time to act is now. ESI

About the company

Landis+Gyr South Africa is an electronic meter manufacturing company that offers a complete range of metering solutions, from prepayment, smart and credit metering to meter test equipment and system solutions. It is a Level 1 BBBEE company that is strongly committed to black economic empowerment, local manufacturing, support of local BEE suppliers, and skills development for South African people.

Visit Landis+Gyr booth C4 at African Utility Week and POWERGEN Africa www.landisgyr.com

This article first appeared in ESI Africa Edition 2, 2019. You can read the magazine's articles here or subscribe here to receive a print copy.