Liaison statement
Use of Chargeable User Identity (CUID) in RADIUS

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State Posted
Submitted Date 2023-10-10
From Group WBA
From Contact Bruno Tomas
To Group madinas
To Contacts Carlos Bernardos <cjbc@it.uc3m.es>
Juan-Carlos Zúñiga <juzuniga@cisco.com>
Cc MAC Address Device Identification for Network and Application Services Discussion List <madinas@ietf.org>
Erik Kline <ek.ietf@gmail.com>
Carlos Bernardos <cjbc@it.uc3m.es>
Éric Vyncke <evyncke@cisco.com>
Juan-Carlos Zúñiga <juzuniga@cisco.com>
Response Contact pmo@wballiance.com
Purpose For information
Attachments WBA-LS IETF MADINAS - CUID - 2023-10-06
Body 
Dear Members of the IETF MADINAS Group,

The objective of the Roaming Work Group (RWG) is to support the development and
maintenance of roaming specifications, guidelines, best practices, and
templates etc. Our group is responsible for maintaining WBA Wireless Roaming
Intermediary eXchange (WRIX) documents published by the WBA to facilitate and
standardize the deployment of Wi-Fi roaming worldwide.

It has come to our attention that because of the discussions at IETF 117
MADINAS meeting, an issue was raised regarding the handling of the Chargeable
User ID Radius attribute #89 (CUID) in the RADIUS exchange. The discussions at
MADINAS highlighted an issue regarding the possibility for privacy leakage
across the interfaces between an IDP and an ANP.

The WBA RWG takes the management of end user privacy very seriously, however;
there are several use cases where the ability to identify unique user
interactions are critical to managing roaming or other use cases. As a result,
the RWG will be reviewing our requirements and best practices in detail with
the intention of clarifying the correct usage and handling of this attribute.

We welcome input and discussion with MADINAS in this review to ensure that end
user privacy is protected while ensuring that business operations can continue.
After the WBA RWG has completed our analysis, we would welcome a joint meeting
to review and discuss recommendations in the first quarter of 2024. For more
information, please contact the WBA PMO (pmo@wballiance.com)

Sincerely,
WBA Roaming Working Group Chairs