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Fix #622: Clarify PublicKeyCredentialEntity name descriptions #666

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merged 9 commits into from
Jan 3, 2018
44 changes: 24 additions & 20 deletions index.bs
Original file line number Diff line number Diff line change
Expand Up @@ -1343,8 +1343,7 @@ optionally evidence of [=user consent=] to a specific transaction.
: <dfn>rp</dfn>
:: This member contains data about the [=[RP]=] responsible for the request.

Its value's {{PublicKeyCredentialEntity/name}} member contains the friendly name of the [=[RP]=] (e.g. "Acme Corporation",
"Widgets, Inc.", or "Awesome Site".
Its value's {{PublicKeyCredentialEntity/name}} member is required.
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RP's "name" is optional according to CTAP spec. See below comment.


Its value's {{PublicKeyCredentialRpEntity/id}} member specifies the [=relying party identifier=] with which the credential
should be associated. If omitted, its value will be the {{CredentialsContainer}} object's [=relevant
Expand All @@ -1353,14 +1352,8 @@ optionally evidence of [=user consent=] to a specific transaction.
: <dfn>user</dfn>
:: This member contains data about the user account for which the [=[RP]=] is requesting attestation.

Its value's {{PublicKeyCredentialEntity/name}} member contains a name for the user account (e.g.,
"john.p.smith@example.com" or "+14255551234").

Its value's {{PublicKeyCredentialUserEntity/displayName}} member contains a friendly name for the user account (e.g.,
"John P. Smith").

Its value's {{PublicKeyCredentialUserEntity/id}} member contains the [=user handle=] for the account, specified by the
[=[RP]=].
Its value's {{PublicKeyCredentialEntity/name}}, {{PublicKeyCredentialUserEntity/displayName}} and
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user's "name" and "displayName" are not required according to CTAP spec. Only user's "id" is required.
For very security conscious RPs, who don't want to store any user identifiable information on the FIDO device, they will only set "id" (which is supposed to be random bytes). There is no UI requirement for single account per RP case.

On FIDO device, RP's "id" and users "id" makes a unique combination to identify a credentials. Rest of the fields are helper details which are optional.

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For an authenticator with a display (or, for example, an authenticator app on a phone), needs this information to show a useful message. "Do you want to register at example.com with Alex P. Mueller?" is a lot more informative (and, I would argue, security conscious) than "Do you want to register?".

Storing this information on the authenticator is more privacy than security sensitive, especially considering that the device is already entrusted with the keys. Perhaps I am biased but I assume authenticator vendors are security and privacy conscious enough to encrypt this additional information. If not, don't buy their products.

For getAssertion, I am fine with making this optional. If the device needs the information, it can store it.

{{PublicKeyCredentialUserEntity/id}} members are required.

: <dfn>challenge</dfn>
:: This member contains a challenge intended to be used for generating the newly created credential's [=attestation
Expand Down Expand Up @@ -1405,10 +1398,18 @@ associated.
</xmp>
<div dfn-type="dict-member" dfn-for="PublicKeyCredentialEntity">
: <dfn>name</dfn>
:: A human-friendly identifier for the entity. For example, this could be a company name for a [=[RP]=], or a
user's name. This identifier is intended for display. [=Authenticators=] MUST accept and store a 64 byte minimum length
for a name members's value. Authenticators MAY truncate a
name member's value to a length equal to or greater than 64 bytes.
:: A human-readable name for the entity. Its function depends on what the {{PublicKeyCredentialEntity}} represents:
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I would s/-readable/-palatable/. And add this note:
"Note: An identifier that is human-palatable is intended to be rememberable and reproducible by typical human users, in contrast to identifiers that are, for example, randomly generated sequences of bits."

c.f. https://www.internet2.edu/media/medialibrary/2013/09/04/internet2-mace-dir-eduperson-200604.html

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Sounds good. I'll change to "palatable" in the ...UserEntity bullet point, but leave the top one as "readable" since that applies to both the User and Rp variants and Rp.name doesn't necessarily need to be reproducible. Does that sound good?

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ok.

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What does copyright legalese say about flat-out copying that definition from the EduPerson spec? Should we reference the EduPerson spec for it?

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As per the 2017-12-13 WG call, this is fair use and attribution is good practice.


- When inherited by {{PublicKeyCredentialRpEntity}} it is a human-friendly identifier for the [=[RP]=], intended only
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s/identifier/name/

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Done!

for display. For example, "ACME Corporation", "Wonderful Widgets, Inc." or "Awesome Site".
- When inherited by {{PublicKeyCredentialUserEntity}}, it is a human-readable identifier for a user account. It is
intended only for display, and SHOULD allow the user to easily tell the difference between user accounts with similar
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well, when inherited by {{PublicKeyCredentialUserEntity}}, an RP MAY use the name member's value to store an account identifier (aka a username), yes?

I'm thinking we should add a Note: wrt an RP's options when employing PublicKeyCredentialUserEntity.id and PublicKeyCredentialUserEntity.name.

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I'm not sure what you mean by your first paragraph. The member is required and won't be passed back to the RP, only (optionally) stored by the authenticator. The RP MAY use name for a username, yes, MUST use it, and SHOULD NOT use it for anything too functionally different from a conventional username.

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see comments below...

{{PublicKeyCredentialUserEntity/displayName}}s. For example, "alexm", alex.p.mueller@acme.com" or "+14255551234". The
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s/, alex.p.mueller/, "alex.p.mueller/

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Good catch, thanks!

[=[RP]=] SHOULD let the user choose this, and MAY restrict the choice as needed or appropriate.
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I suggest: s/ [=[RP]=] SHOULD /=[RP]=] MAY / because this is really up to the RP's deployment context.

Also, after "appropriate.", I would add: "For example, an [=[RP]=] may choose to map human-palatable [=username=] account identifiers to {{PublicKeyCredentialUserEntity}}'s {{PublicKeyCredentialUserEntity/name}}."

..where [=username=] perhaps should link to https://html.spec.whatwg.org/#attr-fe-autocomplete-username (AFAICT, it seems to be the most appropriate place to link "username" to in the greater Web specs space, for our purposes here).

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Apparently, [=username=] already links to https://url.spec.whatwg.org/#concept-url-username . Should we change that?

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Should we change that?

yeah, none of the autolinks for "username" amongst whatwg/w3c specs seemed very satisfying to me, so i was thinking that the link to https://html.spec.whatwg.org/#attr-fe-autocomplete-username would be the most clear for readers in terms of implying that we mean username in the sense of "unique-for-this-rp user account name". Though, I suppose we could just define it as such ourselves.

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Ok, done!


[=Authenticators=] MUST accept and store a 64 byte minimum length for a {{PublicKeyCredentialEntity/name}} members's
value. Authenticators MAY truncate a {{PublicKeyCredentialEntity/name}} member's value to a length equal to or greater
than 64 bytes.

: <dfn>icon</dfn>
:: A [=URL serializer|serialized=] URL which resolves to an image associated with the entity. For example, this could be
Expand Down Expand Up @@ -1451,9 +1452,12 @@ credential.
:: The [=user handle=] of the user account entity.

: <dfn>displayName</dfn>
:: A friendly name for the user account (e.g., "John P. Smith"). [=Authenticators=] MUST accept and store a 64 byte minimum
length for a displayName members's value. Authenticators MAY truncate a
displayName member's value to a length equal to or greater than 64 bytes.
:: A human-friendly name for the user account, intended only for display. For example, "Alex P. Müller" or "田中 倫". The
[=[RP]=] SHOULD let the user choose this, and SHOULD NOT restrict the choice more than necessary.

[=Authenticators=] MUST accept and store a 64 byte minimum length for a {{PublicKeyCredentialUserEntity/displayName}}
members's value. Authenticators MAY truncate a {{PublicKeyCredentialUserEntity/displayName}} member's value to a length
equal to or greater than 64 bytes.
</div>


Expand Down Expand Up @@ -3756,14 +3760,14 @@ The sample code for generating and registering a new key follows:

// Relying Party:
rp: {
name: "Acme"
name: "ACME Corporation"
},

// User:
user: {
id: Uint8Array.from(window.atob("MIIBkzCCATigAwIBAjCCAZMwggE4oAMCAQIwggGTMII="), c=>c.charCodeAt(0)),
name: "john.p.smith@example.com",
displayName: "John P. Smith",
name: "alex.p.mueller@example.com",
displayName: "Alex P. Müller",
icon: "https://pics.acme.com/00/p/aBjjjpqPb.png"
},

Expand Down