Subject: Re: Abstraction from existing technologies

From: Christian Hauser <[email-masked]>
Date: Wed, 25 Jul 2001 16:27:10 +0200 (MEST)

On Jul 24, 11:10, Shahid Shoaib wrote:
> Subject: Re: Abstraction from existing technologies
>
>
> ----- Original Message -----
> From: "Christian Hauser" <[email-masked]>
> To: <[email-masked]>
> Sent: Friday, July 20, 2001 7:35 AM
> Subject: Abstraction from existing technologies
>
> > This entity would know very accurate location information about the
users.
> > Because that information has to be prevented from being linked to the
> users'
> > identities (as I depicted in my mail from July, 12th), this Location
> Service
> > must be usable pseudonymously.
>
> The problem is that where ever the mobile user goes, he has to be
> authenticated first. For example, if the user moves from a UMTS network
> outside to a WLAN network inside a building, he will need to be
> authenticated by the WLAN operator, which will reveal his identity and
> location to the WLAN operator.

In my opinion, authenticating does not necessarily have to imply revealing
a user's real identity. I think, it should be possible to be authenticated
by a pseudonym (perhaps with a trusted third party guaranteeing for the
integrity of the pseudonym and/or for the liquidity of the user). According to the
provider's policy more or less additional information can be bound to that
pseudonym, whatever the provider needs for authentication.

If a user would use different pseudonyms with different providers (what I
would highly recommend), he would have to give them a reference to his location
information in the location service. (This reference should look different
for different pseudonyms in order to disable linkage to the same target by
parties other than the location service.)

Best regards,

Christian Hauser

Institute of Communication Networks and Computer Engineering
University of Stuttgart, Pfaffenwaldring 47, 70569 Stuttgart, Germany

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---

From: Shahid Shoaib <[email-masked]>
Date: Wed, 25 Jul 2001 16:51:15 -0700

Comments inline

----- Original Message -----
From: "Christian Hauser" <[email-masked]>
To: <[email-masked]>
Cc: <[email-masked]>
Sent: Wednesday, July 25, 2001 7:27 AM
Subject: Re: Abstraction from existing technologies

> pseudonym, whatever the provider needs for authentication.

I understand your point. I agree that it may be possible for the users to
get themselves authenticated with different network providers using possibly
different pseudonyms. I have two concerns.

First, will it be possible for the mobile device to do a transparent and
seamless handover (with possibility of session migration) between two
different (or same) access technologies, provided by different operators?

Second, existing UMTS standards require the mobile terminal to have a USIM
at all times. The USIM identifies the user to any UMTS network provider.
Without the USIM no calls or location estimates (except for emergencies) can
be made. Other types of wireless networks do not have this requirement. So
the UMTS operators will always be aware about the real identity of the user.

Best Regards,
Shahid
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Shahid Shoaib                                  +1-408-451-4740 Direct
DoCoMo USA Labs Inc.                  +1-408-573-1090 Fax
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