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June change proposal: service providers

From: Dan Auerbach <dan@eff.org>
Date: Tue, 25 Jun 2013 23:49:46 -0700
Message-ID: <51CA8F0A.7080909@eff.org>
To: "public-tracking@w3.org" <public-tracking@w3.org>
I unfortunately haven't had time to digest the history and current state
of the service provider debate as reflected by the June document. I'm
posting old relevant text so that I don't give up my right to object
about service providers, since I think the text below is more detailed
and requires some important technical controls on the part of service
providers:


A first party may outsource website functionality to a third party, in
which case the third party may act as the first party under this
standard with the following additional restrictions.

1 Technical Precautions

1.1 Operative Text

Throughout all data reception, retention, and use, outsourced service
providers must use all feasible technical precautions to both mitigate
the linkability of and prevent the linking of data from different first
parties.

Structural separation ("siloing") of data per first party, including
both separate data structures and avoidance of shared unique identifiers
are necessary, but not necessarily sufficient, technical precautions.

1.2 Non-Normative Discussion

1.2.1 Siloing in the Browser

Outsourcing services should use browser access control features so that
stored data specific to one first party is never accessed or received
when the user visits another first party.

1.2.1.1 Same-Origin Policy

The same-origin policy silos stored data by domain name. An outsourcing
service can use a different domain name for each first party.

Example: Example Analytics provides an outsourced analytics service to
Example News and Example Sports, two unrelated websites. Example
Analytics stores its cookies for Example News at
examplenews.exampleanalytics.com, and it stores its cookies for Example
Sports at examplesports.exampleanalytics.com.

1.2.1.2 Cookie Path Attribute

The HTTP cookie path can be used to silo data to a first party.

Example: Example Analytics stores its cookies for Example News with
"Path=/examplenews", and it stores its cookies for Example Sports with
"Path=/examplesports".

1.2.1.3 Storage Key

For key/value storage APIs, such as Web Storage and Indexed Database, an
outsourcing service can use a different key or key prefix for each first
party.

Example: Example Analytics stores data for Example News at
window.localStorage["examplenews"] and data for Example Sports at
window.localStorage["examplesports"].

1.2.2 Siloing in the Backend

1.2.2.1 Encryption Keys

An outsourcing service should encrypt each first party's data with a
different set of keys.

1.2.2.2 Access Controls

An outsourcing service should deploy access controls so that only
authorized personnel are able to access siloed data, and only for
authorized purposes.

1.2.2.3 Access Monitoring

An outsourcing service should deploy access monitoring mechanisms to
detect improper use of siloed data.

1.2.3 Retention in the Backend

An outsourcing service should retain information only so long as
necessary to provide necessary functionality to a first party. If a
service creates periodic reports, for example, it should delete the data
used for a report once it is generated. An outsourcing service should be
particularly sensitive to retaining protocol logs, since they may allow
correlating user activity across multiple first parties.

2 Internal Practices

2.1 Operative Text

Throughout all data reception, retention, and use, outsourced service
providers must use sufficient internal practices to prevent the linking
of data from different first parties.

2.2 Non-Normative Discussion

2.2.1 Policy

An outsourcing service should establish a clear internal policy that
gives guidance on how to receive, retain, and use outsourced data in
compliance with this standard.

2.2.2 Training

Personnel that interact with outsourced data should be familiarized with
internal policy on compliance with this standard.

2.2.3 Supervision and Reporting

An outsourcing service should establish a supervision and reporting
structure for detecting improper access.

2.2.4 Auditing

External auditors should periodically examine an outsourcing service to
assess whether it is in compliance with this standard and has adopted
best practices. Auditor reports should be made available to the public.

3 Use Direction

An outsourced service must use data retained on behalf of a first party
ONLY on behalf of that first party, and must not use data retained on
behalf of a first party for their own business purposes, or for any
other reasons.

4 First-Party Requirements

4.1 Representation

A first party's representation that it is in compliance with this
standard includes a representation that its outsourcing service
providers comply with this standard.

4.2 Contract

A first party must enter into a contract with an outsourcing service
provider that requires that outsourcing service provider to comply with
these requirements.



-- 
Dan Auerbach
Staff Technologist
Electronic Frontier Foundation
dan@eff.org
415 436 9333 x134
Received on Wednesday, 26 June 2013 06:50:14 UTC

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