Re: [urn] Informal NID registration interest

[Ted Hardie <[e-mail]>]

Thanks for the reply.  Some additional comments below.

On Tue, Mar 30, 2021 at 8:42 AM Kate Gray <[e-mail]> wrote:

> *From:* Kate Gray <[e-mail]>
> *Sent:* Monday, March 29, 2021 1:40 PM
> *To:* Ted Hardie <[e-mail]>
> *Subject:* Re: [urn] Informal NID registration interest
>
> Answers inline.
>
> ------------------------------
> *From:* Ted Hardie <[e-mail]>
> *Sent:* Monday, March 29, 2021 10:50 AM
> *To:* Kate Gray <[e-mail]>
> *Cc:* [e-mail] <[e-mail]>
> *Subject:* Re: [urn] Informal NID registration interest
>
> Howdy,
>
> Thanks for submitting the registration.  I have a couple of questions,
> inline below.
>
> On Sun, Mar 28, 2021 at 3:05 PM Kate Gray <[e-mail]> wrote:
>
> Hello,
>
> I am interested in registering an informal NID for URNs.
>
> I have attempted to fill out the template as requested.  I apologize if I
> screwed up somewhere; this is my first time doing this.
>
> Namespace Identifier: Assigned by IANA (informal)
>
> Version: 1
>
> Date: 2021-03-28
>
> Registrant:
>     Kate Gray <kate&codebykate.com>
>     340 S Lemon Ave #5926
>     Walnut, CA 91789 USA
>
> Purpose:
>     The purpose of this NID is to provide a Uniform Resource Name
> representing
>     derived keys within a card issuance scheme.  Specifically, they
> provide a
>     path within a hierarchal tree representing implementers (referred to as
>     tenants within the system), card issuers (e.g. Universities), optional
> sub-
>     issuers (e.g. Departments), and individual keys within a card (used for
>     different purposes).
>
>     These URNs will be used by card manufacturers (to preload data for
> issuers),
>     as well as issuers and users to refer to the cards and keys throughout
> the
>     card lifecycle.  Good security practices require the use of diversified
>     (per-card) keys, so that an attacker who defeats the security on a
> card will
>     not have the keys required to attack other cards within the system.
>
>     A cryptographic module (generally a smart card) can be pre-provisioned
> with
>     the issuer keys, and the URN for a given key provided to it.  With this
>     information and cryptographic keying material, the appropriate keys
> can be
>     derived, without the host needing to know the issuer keys.
>
>     While this URN will be implemented into software (including open source
>     software), and published to permit others within the industry to
>     interoperate, it is not expected to become a formal standard, or to be
>     publicly resolvable.  The general use will be between actors in a card
>     issuance scheme, for purposes like enabling a vending machine to
> derive a
>     balance update key for a stored balance wallet on a card, or for a help
>     desk agent to determine the Personal Unblocking Key (PUK) for a user
> that
>     has lost their PIN.
>
> Syntax:
>
>   All URNs defined under the namespace have the following structure,
>   specified in RFC 7405 ABNF notation[1]:
>
>     NSS                = %s"urn:" NID ":" TenantId "@" TenantVersion ":"
>                          IssuerId "@" IssuerVersion ":" Purpose "@"
>                          PurposeVersion "/" ResourceId "@"
> ResourceKeyVersion
>     NID                = "urn" - DIGIT
>     TenantId           = 3*(label)
>     TenantVersion      = version
>     IssuerId           = 3*(label) / 3*(label) ":" 3*(label) / 3*(label)
> ":" 3*(label) ":" 3*(label)
>     IssuerVersion      = version
>
>
> To confirm my understanding here:  the TenantId is associated with the
> software writer who went to the website and requested a new ID.  That
> implementer then manages the uniqueness of the TenantVersion, the IssuerId,
> and IssuerVersion of the NSS.  The latter two are managed by ensuring that
> each IssuerID minted goes only to a single organization? Is that correct?
>
> The tenantID is associated with the implementer of the card issuance
> scheme.  It's functionally similar to a persistent domain name, issued
> without charge and in perpetuity.
>
> The implementer may be a commercial entity, a standards body, or a parent
> organization of some sort.  For example, an organization like the UC system
> might wish to run their own tenant, with issuer keys given to each
> particular university within the system.
>
> The term tenant is used within the scheme because it's intended to allow
> key management software to create separate trees in much the way that Gmail
> and Office 365 have separate tenants within their hosted email solutions.
> Allowing a single piece of software to have multiple tenants allows for
> organizational flexibility in terms of division of responsibility.
>
>
>
>
>     Purpose            = 3*(alphanum / other)
>     PurposeVersion     = version
>     ResourceId         = 1*(alphanum / other)
>     ResourceKeyVersion = version
>     label              = loalpha / loalpha *(alphanum / "-") alphanum
>
>
> I am not sure that I understand the ABNF of "label".  According to section
> 3.6 of RFC 5234, * without a minimum or maximum bound can include zero of
> the following element.  That appears to mean that loalpha alphanum would be
> a legal result.  Is that intended, or is the "-" always present?
>
>
> The intent is that the first character in the label must be lowercase
> alpha.  After that, alpha numeric may be used.  Dashes may be present, but
> if present, must be followed by at least one alpha numeric character.
>
>
I suspect we need to get a full ABNF review here, because I don't think
this ABNF matches your intent (if there must be a loalpha to start, I
believe you need "1*loalpha" followed by the alternatives, for example).
I'm also a little confused by the TenantId and IssuerId construct, because
"3*label" means that there is a minimum of 3 labels.  Because there is no
delimiter between the labels in that construct, it would be hard to
identify where the label boundaries are. That is, I think if someone
presented a TenantId like this:

aXaaa-YbbbGGa

"aX" could be a label but "aXa" could as well, so it is not clear where the
label boundary is.  On the other hand, if your intent is to say that these
labels must be a minimum of 3 characters long,  it is probably easier to
define that within  the "label" rule.

If you use the verification tools here:
https://tools.ietf.org/inventory/verif-tools (e.g. Eustathius or abnfgen),
do the productions match what you expect?



>
>
>     version            = 2*2(HEXDIG)
>     alphanum           = loalpha / DIGIT
>     loalpha            = %x61-7A
>     other              = "-" / "_"
>
>     As the full string of the URN is used as an input to the Key Derivation
>     Function, equivalent URNs are impossible.  As such, the equivalency
> rules
>     consist of bit-by-bit comparisons (Simple String Comparison).
>
> Assignment:
>
>     Registration within this NID is private.
>
>     Implementers will register a Tenant ID, and be responsibile for
> issuers and
>     sub-issuers within their card issuance tenancy.  The web site will be
>     responsible for ensuring that Tenant IDs are unique.
>
>
> Can you specify the website which will issue them?  As written, it might
> be misread to imply that someone else could set up a website to issue
> these, which could result in collisions.
>
>
> Tenant IDs will be registered, free of charge, through the website
> "credentsys.cloud".
>
>
Thank you; I suggest that the template include this information.


>     Uniqueness will be guaranteed through a combination of statistical and
>     database-based methods.  For example, when issuing management for PIV
> cards,
>     the keying material used incudes a UUID that is guaranteed
> mathematically to
>     be unique.  In contrast, when deriving GlobalPlatform keys (which use
> a 10
>     byte unique ID for the card), issuers will be responsible for keeping a
>     record of all such cards issued and ensuring there are no duplicate
> IDs.
>
>
> GlobalPlatform keys do not appear to be referenced in the ABNF above.  Are
> these a sub type of the ResourceID?  If so, given these examples, is 1
> really the minimum number of characters for a ResourceID?
>
>
> That was intended as an example.  Different applets and card types provide
> different identifiers.  GlobalPlatform (the most common type of key) only
> allows 10 characters for derivation.  The goal is to ultimately be platform
> agnostic.
>

It might be useful to note that this is an example in the template.  I
would also be surprised if a single character could be useful ID, but if
this is your preferred minimum, it is up to you.



>
>
>
>     Because each issuer is at a unique path within the hierarchal tree,
>     uniqueness is guaranteed as long as they take care not to issue
> duplicate
>     cards within their own subtree.
>
> Security and Privacy:
>
>     As these identifiers will be used in the generation of cryptographic
> keys,
>     their opacity does serve to provide a degree of "security through
> obscurity"
>     for attackers looking to compromise the cards.  The loss of that
> obscurity
>     (for example, if an attacker is able to find a users card ID in the
> browser
>     history) in theory represents a slight loss of security for the user.
>
>     Keys for this system will be stored in Hardware Security Modules
> (HSMs), and
>     configured such that the actual keying material for that level never
> leaves
>     the cryptographic envelope.  Through the use of hash functions that
> provide
>     strong cryptographic guarantees, and hardware security on the keys
>     themselves, there is no need for the identifiers to be private, and no
> risk
>     to the user should an attacker somehow gain access to his identifier
> without
>     having additionally compromised the HSM or a machine connected to the
> HSM.
>
>     In a broader sense, the point of this card issuance scheme is to
> facilitate
>     the issuance of privacy-protecting and security-enhancing credentials
> to
>     individuals within organizations.  Such cards permit strong
> authentication,
>     as well as multi-factor logins that are resistant to phishing and which
>     enable mutual authentication from the server level.  As such, the net
> effect
>     on Privacy and Security will be positive.
>
> Evaluating the system described is beyond the scope of the URN review
> process, but I will say that the description above seems to place a great
> deal of stress on the HSM and not much on what other inputs the hash
> function has and what properties are available to update the hash function
> used.  If you desire such a review, I believe the IETF security area
> advisory group ([e-mail]) could provide that.
>
>
> Thank you for the recommendation.
>
>
Thanks again for your reply and registration.

best regards,

Ted Hardie


>
>
> Interoperability:
>
>     The author is not aware of any potential conflicts with this
> namespace, and
>     given the rather tightly coupled nature of the identifier with the
>     implementation, any overlapping areas of concern for other systems
> should
>     not present interoperability issues, as there will be no operability.
>
> Resolution:
>
>     Resolution mechanisms are not intended or anticipated for this
> namespace.
>
>
> Thanks again for submitting the registration.
>
> regards,
>
> Ted Hardie
>
>
> _______________________________________________
> urn mailing list
> [e-mail]
> https://www.ietf.org/mailman/listinfo/urn
>
>
> ------------------------------
> *From:* Ted Hardie <[e-mail]>
> *Sent:* Monday, March 29, 2021 10:50 AM
> *To:* Kate Gray <[e-mail]>
> *Cc:* [e-mail] <[e-mail]>
> *Subject:* Re: [urn] Informal NID registration interest
>
> Howdy,
>
> Thanks for submitting the registration.  I have a couple of questions,
> inline below.
>
> On Sun, Mar 28, 2021 at 3:05 PM Kate Gray <[e-mail]> wrote:
>
> Hello,
>
> I am interested in registering an informal NID for URNs.
>
> I have attempted to fill out the template as requested.  I apologize if I
> screwed up somewhere; this is my first time doing this.
>
> Namespace Identifier: Assigned by IANA (informal)
>
> Version: 1
>
> Date: 2021-03-28
>
> Registrant:
>     Kate Gray <kate&codebykate.com>
>     340 S Lemon Ave #5926
>     Walnut, CA 91789 USA
>
> Purpose:
>     The purpose of this NID is to provide a Uniform Resource Name
> representing
>     derived keys within a card issuance scheme.  Specifically, they
> provide a
>     path within a hierarchal tree representing implementers (referred to
> as
>     tenants within the system), card issuers (e.g. Universities), optional
> sub-
>     issuers (e.g. Departments), and individual keys within a card (used for
>     different purposes).
>
>     These URNs will be used by card manufacturers (to preload data for
> issuers),
>     as well as issuers and users to refer to the cards and keys throughout
> the
>     card lifecycle.  Good security practices require the use of diversified
>     (per-card) keys, so that an attacker who defeats the security on a
> card will
>     not have the keys required to attack other cards within the system.
>
>     A cryptographic module (generally a smart card) can be pre-provisioned
> with
>     the issuer keys, and the URN for a given key provided to it.  With this
>     information and cryptographic keying material, the appropriate keys
> can be
>     derived, without the host needing to know the issuer keys.
>
>     While this URN will be implemented into software (including open source
>     software), and published to permit others within the industry to
>     interoperate, it is not expected to become a formal standard, or to be
>     publicly resolvable.  The general use will be between actors in a card
>     issuance scheme, for purposes like enabling a vending machine to
> derive a
>     balance update key for a stored balance wallet on a card, or for a help
>     desk agent to determine the Personal Unblocking Key (PUK) for a user
> that
>     has lost their PIN.
>
> Syntax:
>
>   All URNs defined under the namespace have the following structure,
>   specified in RFC 7405 ABNF notation[1]:
>
>     NSS                = %s"urn:" NID ":" TenantId "@" TenantVersion ":"
>                          IssuerId "@" IssuerVersion ":" Purpose "@"
>                          PurposeVersion "/" ResourceId "@"
> ResourceKeyVersion
>     NID                = "urn" - DIGIT
>     TenantId           = 3*(label)
>     TenantVersion      = version
>     IssuerId           = 3*(label) / 3*(label) ":" 3*(label) / 3*(label)
> ":" 3*(label) ":" 3*(label)
>     IssuerVersion      = version
>
>
> To confirm my understanding here:  the TenantId is associated with the
> software writer who went to the website and requested a new ID.  That
> implementer then manages the uniqueness of the TenantVersion, the IssuerId,
> and IssuerVersion of the NSS.  The latter two are managed by ensuring that
> each IssuerID minted goes only to a single organization? Is that correct?
>
>
>
>     Purpose            = 3*(alphanum / other)
>     PurposeVersion     = version
>     ResourceId         = 1*(alphanum / other)
>     ResourceKeyVersion = version
>     label              = loalpha / loalpha *(alphanum / "-") alphanum
>
>
> I am not sure that I understand the ABNF of "label".  According to section
> 3.6 of RFC 5234, * without a minimum or maximum bound can include zero of
> the following element.  That appears to mean that loalpha alphanum would be
> a legal result.  Is that intended, or is the "-" always present?
>
>
>
>     version            = 2*2(HEXDIG)
>     alphanum           = loalpha / DIGIT
>     loalpha            = %x61-7A
>     other              = "-" / "_"
>
>     As the full string of the URN is used as an input to the Key
> Derivation
>     Function, equivalent URNs are impossible.  As such, the equivalency
> rules
>     consist of bit-by-bit comparisons (Simple String Comparison).
>
> Assignment:
>
>     Registration within this NID is private.
>
>     Implementers will register a Tenant ID, and be responsibile for
> issuers and
>     sub-issuers within their card issuance tenancy.  The web site will be
>     responsible for ensuring that Tenant IDs are unique.
>
>
> Can you specify the website which will issue them?  As written, it might
> be misread to imply that someone else could set up a website to issue
> these, which could result in collisions.
>
>
>     Uniqueness will be guaranteed through a combination of statistical and
>     database-based methods.  For example, when issuing management for PIV
> cards,
>     the keying material used incudes a UUID that is guaranteed
> mathematically to
>     be unique.  In contrast, when deriving GlobalPlatform keys (which use
> a 10
>     byte unique ID for the card), issuers will be responsible for keeping a
>     record of all such cards issued and ensuring there are no duplicate
> IDs.
>
>
> GlobalPlatform keys do not appear to be referenced in the ABNF above.  Are
> these a sub type of the ResourceID?  If so, given these examples, is 1
> really the minimum number of characters for a ResourceID?
>
>
>
>     Because each issuer is at a unique path within the hierarchal tree,
>     uniqueness is guaranteed as long as they take care not to issue
> duplicate
>     cards within their own subtree.
>
> Security and Privacy:
>
>     As these identifiers will be used in the generation of cryptographic
> keys,
>     their opacity does serve to provide a degree of "security through
> obscurity"
>     for attackers looking to compromise the cards.  The loss of that
> obscurity
>     (for example, if an attacker is able to find a users card ID in the
> browser
>     history) in theory represents a slight loss of security for the user.
>
>     Keys for this system will be stored in Hardware Security Modules
> (HSMs), and
>     configured such that the actual keying material for that level never
> leaves
>     the cryptographic envelope.  Through the use of hash functions that
> provide
>     strong cryptographic guarantees, and hardware security on the keys
>     themselves, there is no need for the identifiers to be private, and no
> risk
>     to the user should an attacker somehow gain access to his identifier
> without
>     having additionally compromised the HSM or a machine connected to the
> HSM.
>
>     In a broader sense, the point of this card issuance scheme is to
> facilitate
>     the issuance of privacy-protecting and security-enhancing credentials
> to
>     individuals within organizations.  Such cards permit strong
> authentication,
>     as well as multi-factor logins that are resistant to phishing and which
>     enable mutual authentication from the server level.  As such, the net
> effect
>     on Privacy and Security will be positive.
>
> Evaluating the system described is beyond the scope of the URN review
> process, but I will say that the description above seems to place a great
> deal of stress on the HSM and not much on what other inputs the hash
> function has and what properties are available to update the hash function
> used.  If you desire such a review, I believe the IETF security area
> advisory group ([e-mail]) could provide that.
>
>
>
> Interoperability:
>
>     The author is not aware of any potential conflicts with this
> namespace, and
>     given the rather tightly coupled nature of the identifier with the
>     implementation, any overlapping areas of concern for other systems
> should
>     not present interoperability issues, as there will be no operability.
>
> Resolution:
>
>     Resolution mechanisms are not intended or anticipated for this
> namespace.
>
>
> Thanks again for submitting the registration.
>
> regards,
>
> Ted Hardie
>
>
> _______________________________________________
> urn mailing list
> [e-mail]
> https://www.ietf.org/mailman/listinfo/urn
>
> _______________________________________________
> urn mailing list
> [e-mail]
> https://www.ietf.org/mailman/listinfo/urn
>