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<p class="MsoNormal"><span lang="EN-US" style="mso-fareast-language:EN-US">Hi Tom,<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="mso-fareast-language:EN-US">Thanks for your input! But to clarify: The spec doesn’t use TLS.<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="mso-fareast-language:EN-US">Are you aware of ongoing development using this standard?<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="mso-fareast-language:EN-US">Best,<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="mso-fareast-language:EN-US">Felix<o:p></o:p></span></p>
<p class="MsoNormal"><span style="mso-fareast-language:EN-US"><o:p> </o:p></span></p>
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<p class="MsoNormal"><b><span style="font-size:12.0pt;color:black">From: </span></b><span style="font-size:12.0pt;color:black">Tom Jones <thomasclinganjones@gmail.com><br>
<b>Date: </b>Saturday, 11 November 2023 at 18:04<br>
<b>To: </b>Digital Credentials Protocols List <openid-specs-digital-credentials-protocols@lists.openid.net><br>
<b>Cc: </b>Linker Felix <flinker@inf.ethz.ch><br>
<b>Subject: </b>Re: [Openid-specs-digital-credentials-protocols] Formal Analysis - OpenID for Verifiable Presentations over BLE - draft 00<o:p></o:p></span></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">Generally I have been opposed to channel binding using tls as tls is not generally available at the application level. I like the idea here if it can be fully controlled at the application level. We still have the problem of channel establishment
but I have a solution for that as well. <o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">This isn't so much a pr as a reboot of the whole project.<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">The challenge will be integration with phone OS.<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal" style="margin-bottom:12.0pt">I think this is a case where the implementations should drive the standard rather than the other way around.<o:p></o:p></p>
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<p class="MsoNormal">thx ..Tom (mobile)<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">On Sat, Nov 11, 2023, 3:48 AM Linker Felix via Openid-specs-digital-credentials-protocols <<a href="mailto:openid-specs-digital-credentials-protocols@lists.openid.net">openid-specs-digital-credentials-protocols@lists.openid.net</a>> wrote:<o:p></o:p></p>
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<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US">Hi all,</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US"> </span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US">Earlier this year, I started a formal analysis of the OpenID for Verifiable Presentations over BLE draft 00 and shared my early results in a call. IETF motivated
me to finalize my work and I thus finished my formal Tamarin models and opened a pull request to the specification proposing two changes to improve its security properties. Notably, in comparison to my results from earlier this year, I changed my proposed
fixes. </span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US"> </span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US">Exec. summary: The specification does not sufficiently bind the messages exchanged over the BLE channel to that channel. Thus, an interceptor can both acquire
VP tokens not intended for them, and make a verifier believe that a device under the control of an attacker exchanged a VP token with them. I propose to fix this by authenticating the two ephemeral ECDH half-keys used for connection establishment. Details
in the PR.</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US"> </span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US">You can find a repository that describes my findings of the formal analysis here:
</span><a href="https://github.com/felixlinker/tamarin_openid4vp_ble" target="_blank">felixlinker/tamarin_openid4vp_ble (github.com)</a><span lang="EN-US"> I tried to stay brief!</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US"> </span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US">You can find my PR here:
</span><a href="https://github.com/openid/openid4vp_ble/pull/46" target="_blank">Formal Analysis Results by felixlinker · Pull Request #46 · openid/openid4vp_ble (github.com)</a><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"> <o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US">Are there any questions?
</span><span lang="DE" style="font-family:"Apple Color Emoji"">😊</span><span lang="DE">
</span><span lang="EN-US">Should I join one of the calls to discuss the findings?</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US"> </span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US">I hope this brings some value to the spec!</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US"> </span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US">Best,</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US">Felix</span><o:p></o:p></p>
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<p class="MsoNormal">-- <br>
Openid-specs-digital-credentials-protocols mailing list<br>
<a href="mailto:Openid-specs-digital-credentials-protocols@lists.openid.net" target="_blank">Openid-specs-digital-credentials-protocols@lists.openid.net</a><br>
<a href="https://lists.openid.net/mailman/listinfo/openid-specs-digital-credentials-protocols" target="_blank">https://lists.openid.net/mailman/listinfo/openid-specs-digital-credentials-protocols</a><o:p></o:p></p>
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