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Adapt PID rulebook to latest SD-JWT VC #160

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Adapt PID rulebook to latest SD-JWT VC
danielfett Mar 26, 2024
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Update docs/annexes/annex-06-pid-rulebook.md
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222 changes: 184 additions & 38 deletions docs/annexes/annex-3/annex-3.01-pid-rulebook.md
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Expand Up @@ -23,10 +23,10 @@ This PID Rulebook contains the following topics:
organization of the mandatory and optional attributes of the PID. It
also describes how Member States can specify any possible national
attributes. Two encodings for these attributes are specified, one
compliant with \[ISO18013-5\], the other compliant with \[SD-JWT\].
compliant with \[ISO18013-5\], the other compliant with \[SD-JWT VC\].

- [Chapter 3](#23-pid-attributes) specifies details about the trust infrastructure necessary
for PIDs, for both ISO/IEC 18013-5-compliant and SD-JWT-compliant
- [Chapter 3](#3-trust-infrastructure-details) specifies details about the trust infrastructure necessary
for PIDs, for both ISO/IEC 18013-5-compliant and SD-JWT-VC-compliant
encodings. This information may be moved to another document in the
future.

Expand Down Expand Up @@ -56,8 +56,8 @@ This chapter describes the structure, type, attribute identifiers and
logical organisation of the mandatory and optional attributes of the PID
within the EUDI Wallet, as well as the PID metadata:

- [Section 2.2](#22-attestation-type-and-namespace) specifies the attestation type and namespace(s) for a
PID:
- [Section 2.2](#22-attestation-type-and-namespace-iso-format) specifies the attestation type and namespace(s) for a
PID in ISO/IEC 18013-5 format:

- [Section 2.2.1](#221-eu-wide-attestation-type-and-namespace-for-pid) specifies the PID attestation type and the EU-wide
PID namespace within which the PID attributes defined in this
Expand All @@ -66,14 +66,17 @@ within the EUDI Wallet, as well as the PID metadata:
- [Section 2.2.2](#222-domestic-pid-namespaces-for-national-attributes) describes how Member States can specify national
attributes by defining a domestic PID namespace.

- [Section 2.3](#23-pid-attributes) specifies the set of PID attributes.
- [Section 2.3](#23-sd-jwt-vc-type) specifies the SD-JWT VC Type to be used for PID
attestations in SD-JWT VC format.

- [Section 2.4](#24-pid-attribute-encodings) specifies two different encodings for these attributes.
- [Section 2.4](#24-pid-attributes) specifies the set of PID attributes.

- [Section 2.5](#25-pid-attribute-encodings) specifies two different encodings for these attributes.
The first encoding uses Concise Binary Object Representation (CBOR)
and complies with ISO/IEC 18013-5:2021 \[ISO18013-5\]. The second
encoding uses JSON and complies with \[SD-JWT\] and \[OpenID4VP\].
encoding uses JSON and complies with \[SD-JWT VC\].

### 2.2 Attestation type and namespace
### 2.2 Attestation type and namespace (ISO format)

#### 2.2.1 EU-wide attestation type and namespace for PID

Expand Down Expand Up @@ -101,8 +104,7 @@ Note that the attestation type and namespace have the same value. This
is allowed according to ISO/IEC 18013-5.

PID Providers SHALL use this attestation type and namespace for the
ISO/IEC 18013-5 compliant attribute encoding specified in [Section 2.4.2](#242-isoiec-18013-5-compliant-encoding)
and for the SD-JWT-compliant encoding in [Section 2.4.3](#243-sd-jwt-compliant-encoding).
ISO/IEC 18013-5 compliant attribute encoding specified in [Section 2.4.2](#242-isoiec-18013-5-compliant-encoding) only.

#### 2.2.2 Domestic PID namespaces for national attributes

Expand All @@ -123,18 +125,59 @@ EXAMPLE: The first domestic PID namespace for Germany could be
"eu.europa.ec.eudi.pid.de.1".

PID Providers SHALL use the same domestic namespace for both ISO/IEC
18013-5-compliant PIDs and SD-JWT-compliant PIDs, see Section 2.4.
18013-5-compliant PIDs and SD-JWT-compliant PIDs, see section 2.5.

A PID Provider that defines a domestic namespace SHALL publish the
namespace, including all attribute identifiers, their definition,
presence and encoding format, in a Rulebook complying with all
applicable requirements in \[[Topic 12](../annex-2/annex-2-high-level-requirements.md#a2312-topic-12---attestation-rulebooks)\].

### 2.3 PID attributes

#### 2.3.1 Introduction

PID attributes are defined in Table 1 in [Section 2.3.2](#232-overview).
### 2.3 SD-JWT VC Type

SD-JWT VC defines the Verifiable Credential Type (`vct`). A type comes
with associated metadata that, for instance, provides information about
the type itself, outlines a schema detailing the claims that are
optional or mandatory in the SD-JWT VC, and specifies their display
methods. Additionally, a type can inherit from another type, enabling
the creation of domestic types based on a broader EU-wide standard. The
information regarding a type can be automatically discovered.

The information provided in this document SHALL be specified as a
Verifiable Credential Type in the format defined by SD-JWT VC, including
a schema for PIDs, display (rendering) information, and other metadata
specified by SD-JWT VC. This base type SHALL be identified by the URN
`urn:eu.europa.ec.eudi:pid:1`. The version number "1" in this type MAY
be used to distinguish between the first version of the PID attribute
(defined in this document) and any future version.

Domestic PID types for national attributes SHALL be defined using URLs
and extend the EU-wide PID type. It is RECOMMENDED to implement a
national base type and an extension for each version of the type. More
than one domestic PID type MAY be defined per Member State. Domestic PID
types SHALL specify in their Type Metadata any additional fields/claims
and MAY define display information.

EXAMPLE: For Germany, two Verifiable Credential Types for PIDs could be
defined initially:

* `https://example.bmi.bund.de/credential/pid/` as the national base
type, where in the metadata of the type, the `extends` field would
reference the EU-wide type `urn:eu.europa.ec.eudi:pid:1`. This base
type would not define schema or display information, as these are
defined in the concrete versions of the type.
* `https://example.bmi.bund.de/credential/pid/1.0` as the first version
of the national credential type, defining in its metadata schema and
display information. The `extends` field would reference the base
type `https://example.bmi.bund.de/credential/pid/`.

Domestic PID Type Metadata information SHALL be published at their
respective URLs as defined in the SD-JWT VC specification.

### 2.4 PID attributes

#### 2.4.1 Introduction

PID attributes are defined in Table 1 in [section 2.4.2](#242-overview).

Table 1 contains the following information:

Expand All @@ -160,7 +203,7 @@ Table 1 contains the following information:
> mandatory attribute if requested.

- The fourth column indicates how the attributes SHALL be encoded,
using the CDDL representation types defined in \[[RFC 8610](https://www.rfc-editor.org/rfc/rfc8610.html)\]. [Section 2.4](#24-pid-attribute-encodings) specifies how these representation types SHALL be serialized
using the CDDL representation types defined in \[[RFC 8610](https://www.rfc-editor.org/rfc/rfc8610.html)\]. [Section 2.5](#25-pid-attribute-encodings) specifies how these representation types SHALL be serialized
into CBOR and JSON data structures, respectively. Note the
following:

Expand All @@ -185,7 +228,7 @@ Table 1 contains the following information:
- A local offset from UTC SHALL NOT be used; the time-offset
defined in \[[RFC 3339](https://datatracker.ietf.org/doc/html/rfc3339)\] SHALL be to "Z".

#### 2.3.2 Overview
#### 2.4.2 Overview

| **Attribute identifier** | **Definition** | **Presence** | **Encoding format** |
|----------|-------------|--------------|---------------|
Expand All @@ -212,7 +255,7 @@ Table 1 contains the following information:
| resident_street | The name of the street where the PID User currently resides. | O* | tstr |
| resident_house_number | The house number where the PID User currently resides, including any affix or suffix. | O* | tstr |
| gender | PID User's gender, using a value as defined in ISO/IEC 5218. | O* | uint |
| nationality | Alpha-2 country code as specified in ISO 3166-1, representing the nationality of the PID User. | O* | See Section 2.3.6 |
| nationality | Alpha-2 country code as specified in ISO 3166-1, representing the nationality of the PID User. | O* | See section 2.4.6 |
| issuance_date | Date (and possibly time) when the PID was issued. | M | tdate or full-date |
| expiry_date | Date (and possibly time) when the PID will expire. | M | tdate or full-date |
| issuing_authority | Name of the administrative authority that has issued this PID instance, or the ISO 3166 Alpha-2 country code of the respective Member State if there is no separate authority authorized to issue PIDs. | M | tstr |
Expand All @@ -224,9 +267,9 @@ Table 1 contains the following information:
**Table 1 PID attributes**

Note: For the attributes for which the presence is indicated as O\*, see
[Section 2.3.7](#237-minimum-number-of-optional-attributes).
[section 2.4.7](#247-minimum-number-of-optional-attributes).

#### 2.3.3 Date of birth-related attributes
#### 2.4.3 Date of birth-related attributes

This document defines the following attributes related to the date of
birth of the PID User:
Expand Down Expand Up @@ -263,7 +306,7 @@ look at first sight. The examples in Annex D.2.2 of ISO/IEC 18013-5 will
help to understand how the age_over_NN attribute is to be used and
interpreted.

#### 2.3.4 Place of birth-related attributes
#### 2.4.4 Place of birth-related attributes

This document defines the following attributes related to the place of
birth of the PID User:
Expand All @@ -280,7 +323,7 @@ Having multiple attributes instead of a single one allows having
different levels of granularity for requests and responses, and thus
allows PID Providers and Relying Parties to practice data minimization.

#### 2.3.5 Address-related attributes
#### 2.4.5 Address-related attributes

This document defines the following attributes related to the current
address of the PID Users
Expand Down Expand Up @@ -313,7 +356,7 @@ least the resident city, as there will be many duplicate street names
and house numbers in a given country. These attributes have been added
primarily to assist in, for example, automated form filling.

#### 2.3.6 Nationality
#### 2.4.6 Nationality

The nationality or citizenship of the PID User is potentially a
multi-valued attribute, because a citizen can have more than one
Expand All @@ -322,7 +365,7 @@ taking as its value a single Alpha-2 country code. This implies that any
additional nationality of the PID User must be added by the respective
Member State as a domestic attribute, see [Section 2.2.2](#222-domestic-pid-namespaces-for-national-attributes).

#### 2.3.7 Minimum number of optional attributes
#### 2.4.7 Minimum number of optional attributes

PID Providers SHALL include at least four of the following six
attributes (whose presence is indicated as O\* in Table 1) in each PID,
Expand Down Expand Up @@ -370,9 +413,9 @@ defined in Table 1:

- resident_house_number

### 2.4 PID attribute encodings
### 2.5 PID attribute encodings

#### 2.4.1 Introduction
#### 2.5.1 Introduction

\[[Topic 10](../annex-2/annex-2-high-level-requirements.md#a2310-topic-10---issuing-a-pid-or-attestation-to-the-eudi-wallet)/[23](../annex-2/annex-2-high-level-requirements.md#a2310-topic-10---issuing-a-pid-or-attestation-to-the-eudi-wallet)\] specifies that PID must be issued in both the format
specified in ISO/IEC 18013-5:2021 \[ISO18013-5\] and the format
Expand All @@ -381,20 +424,19 @@ be encoded in JSON. For the former, attributes must be encoded in CBOR.

This section therefore specifies two separate encodings for the PID data
model, an ISO/IEC 18013-5-compliant encoding in CBOR, and an
SD-JWT-compliant encoding in JSON.
SD-JWT-VC-compliant encoding in JSON.

#### 2.4.2 ISO/IEC 18013-5-compliant encoding
#### 2.5.2 ISO/IEC 18013-5-compliant encoding

##### 2.4.2.1 Encoding rules
##### 2.5.2.1 Encoding rules

If attributes specified in Table 1 are encoded with CBOR, they SHALL
be encoded as specified in \[[RFC 8949](https://datatracker.ietf.org/doc/html/rfc8949)\].

The CDDL representation types used in Table 1 are specified in [Section 2.3.1](#231-introduction-introduction-1).
Rules to encode CDDL representation types with CBOR are specified in
The CDDL representation types used in Table 1 are specified in [section 2.4.1](#241-introduction-introduction-1). Rules to encode CDDL representation types with CBOR are specified
\[RFC 8610\] and \[[RFC 8949](https://datatracker.ietf.org/doc/html/rfc8949)\].

##### 2.4.2.2 Further stipulations
##### 2.5.2.2 Further stipulations

The value of all attributes (both PID attributes and PID metadata) SHALL
be valid at the value of the timestamp in the validFrom element in the
Expand Down Expand Up @@ -433,14 +475,14 @@ Instance.

All attributes in Table 1 SHALL be made selectively disclosable.

#### 2.4.3 SD-JWT-compliant encoding
#### 2.5.3 SD-JWT-compliant encoding

##### 2.4.3.1 Encoding rules
##### 2.5.3.1 Encoding rules

If attributes are encoded with JSON, they SHALL be encoded as specified
in \[RFC 8259\].

The CDDL representation types used in Table 1 are specified in [Section 2.3.1](#231-introduction-introduction-1). Rules to encode CDDL representation types with JSON are specified
The CDDL representation types used in Table 1 are specified in [Section 2.4.1](#241-introduction-introduction-1). Rules to encode CDDL representation types with JSON are specified
in \[[RFC 8949](https://datatracker.ietf.org/doc/html/rfc8949)\] Section 6.1.
Given the CDDL representation types used in the current version of this document, the following rules are relevant:

Expand Down Expand Up @@ -480,7 +522,111 @@ If other CDDL representation types will be used in future versions of
this document, the corresponding rules for encoding them with JSON will
be added here.

##### 2.4.3.2 Further stipulations

##### 2.5.3.2 Data Element Identifer to Claim Mapping

SD-JWT encoded PID attestations SHALL use claim names registered in the
JSON Web Token Claims Registry \[IANA-JWT-Claims\]. Table 2 below maps
the data element identifiers from Table 1 above to the corresponding
claim names.

Note that a hierarchical claim name structure can be used in SD-JWT VC
encoded PID attestations as SD-JWT allows for individual selective
disclosure of objects and their properties. A hierarchical claim name
structure is indicated by the notation `parent.child` in Table 3.

Data element identifiers not listed in Table 3 are used as defined above.

| Data Element Identifier | Claim Name | Note |
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Would it make sense to have next to each register claim a reference ?
For instance,

Attribute identifier Claim Name Note Reference
family_name family_name OpenID Connect Core 1.0, Section 5.1
given_name given_name OpenID Connect Core 1.0, Section 5.1
birth_date birthdate OpenID Connect Core 1.0, Section 5.1
age_over_18 age_equal_or_over.18 The 18 property name is a string. PID rulebook
age_over_NN age_equal_or_over.NN The NN property name is a string. PID rulebook
age_in_years age_in_years PID rulebook
age_birth_year age_birth_year PID rulebook
family_name_birth birth_family_name OpenID Connect for Identity Assurance Claims Registration 1.0, Section 4
given_name_birth birth_given_name OpenID Connect for Identity Assurance Claims Registration 1.0, Section 4
birth_place place_of_birth.locality OpenID Connect for Identity Assurance Claims Registration 1.0, Section 4
birth_country place_of_birth.country OpenID Connect for Identity Assurance Claims Registration 1.0, Section 4
birth_state place_of_birth.region OpenID Connect for Identity Assurance Claims Registration 1.0, Section 4
birth_city place_of_birth.locality OpenID Connect for Identity Assurance Claims Registration 1.0, Section 4
resident_address address.formatted OpenID Connect for Identity Assurance Claims Registration 1.0, Section 4
resident_country address.country OpenID Connect for Identity Assurance Claims Registration 1.0, Section 4
resident_state address.region OpenID Connect for Identity Assurance Claims Registration 1.0, Section 4
resident_city address.locality OpenID Connect for Identity Assurance Claims Registration 1.0, Section 4
resident_postal_code address.postal_code OpenID Connect for Identity Assurance Claims Registration 1.0, Section 4
resident_street address.street_address OpenID Connect for Identity Assurance Claims Registration 1.0, Section 4
resident_house_number address.house_number OpenID Connect for Identity Assurance Claims Registration 1.0, Section 4
gender gender Data type mismatch - JWT claims use male, female and custom text values.* OpenID Connect for Identity Assurance Claims Registration 1.0, Section 4
nationality nationalities Defined as an array, here containing only one entry. OpenID Connect for Identity Assurance Claims Registration 1.0, Section 4
issuance_date iat RFC7519
expiry_date exp RFC7519
issuing_authority issuing_authority PID rulebook
document_number document_number PID rulebook
administrative_number administrative_number PID rulebook
issuing_country issuing_country PID rulebook
issuing_jurisdiction issuing_jurisdiction PID rulebook

|---|---|---|
| `birth_date` | `birthdate` | |
| `age_over_18` | `age_equal_or_over.18` | Note: The `18` property name is a string.|
| `age_over_NN` | `age_equal_or_over.NN` | Note: The NN property name is a string. |
| `family_name_birth` | `birth_family_name` | |
| `given_name_birth` | `birth_given_name` | |
| `birth_place` | `place_of_birth.locality` | * |
| `birth_country` | `place_of_birth.country` | |
| `birth_state` | `place_of_birth.region` | |
| `birth_city` | `place_of_birth.locality` | |
| `resident_address` | `address.formatted` | |
| `resident_country` | `address.country` | |
| `resident_state` | `address.region` | |
| `resident_city` | `address.locality` | |
| `resident_postal_code` | `address.postal_code` | |
| `resident_street` | `address.street_address` | * |
| `resident_house_number` | `address.house_number` | * |
| `gender` | `gender` | Note: Data type mismatch - JWT claims use `male`, `female` and custom text values.* |
| `nationality` | `nationalities` | Note: Defined as an array, here containing only one entry.|
| `issuance_date` | `iat` | |
| `expiry_date` | `exp` | |
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issuance_date and iat are not necessarily the same thing. The same applies to expiry_date and exp. Compare this to the mdoc PID. The mdoc PID issuance_date and expiry_date attributes are separate from the MSO signed and validUntil timestamps.

issuance_date and expiry_date likely express the administrative validity of the PID while iat and exp express the validity of the JWT which might be considerably shorter than the administrative validity.


*Table 2: Data Element Identifier to Claim Name Mapping*

Fields marked with (*) indicate that there is not a one-to-one mapping
between the data element and a suitable pre-defined JWT claim.
This should be resolved in future versions of this document.

EXAMPLE: The following example shows a PID in SD-JWT VC format.

```json
{
"vct": "https://memberstate.example/credential/pid",
"vct#integrity": "sha384-JjSmVgyd0p3pXB1rRibZUAYoIIy6OrQ6VrjIEaFf/nJGzIxFDsf4x0xIM+B07jRM",

"given_name": "Jean",
"family_name": "Dupont",
"birthdate": "1980-05-23",

"age_equal_or_over": {
"12": true,
"14": true,
"16": true,
"18": true,
"21": true,
"65": false
},
"age_in_years": 44,
"age_birth_year": 1980,

"address": {
"street_address": "123 Via Appia",
"locality": "Rome",
"region": "Lazio",
"postal_code": "00100",
"country": "IT"
},

"nationalities": ["FR"],

"gender": "male",

"place_of_birth": {
"locality": "Leipzig",
"region": "Saxony",
"country": "DD"
},

"cnf": {
"jwk": {
"kty": "EC",
"crv": "P-256",
"x": "52aDI_ur05n1f_p3jiYGUU82oKZr3m4LsAErM536crQ",
"y": "ckhZ-KQ5aXNL91R8Eufg1aOf8Z5pZJnIvuCzNGfdnzo"
}
},

"issuing_authority": "DE",
"issuing_country": "DE"
}
```
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I think it would be helpful to the reader to have an example of the JWT claim set of the SD-JWT.
Especially to demonstrate the requirement to have selectively disclosable the attributes of claims like age_equal_or_over, address etc.

For instance,

{
    "vct": "https://memberstate.example/credential/pid",
    "vct#integrity": "sha384-JjSmVgyd0p3pXB1rRibZUAYoIIy6OrQ6VrjIEaFf/nJGzIxFDsf4x0xIM+B07jRM",
    
    "_sd": [
        "4WIgurnNMUzWOG3sbmmVbhcZScJ2coGwSbmcZrPtumA",
        "XQMnqxzAbDMg-H0XQvS99IrW7Mpl4D2zTBRyfmQgTKY",
        "YtWxyVoyG-gFNACWviWRXHsl1X4RtYSjB22Mspc4Zy0",
        "cACZqNooaasU06tJB4wbqd8a2BWrx2h-nh-QnrE4CGM",
        "fCJZUjADw2ZYmtWHy_AM-rOf9I_YnxUczsYhwpkbpaI",
        "gaxq0QkII8P_QmhGSSaiCPJRuoPIFiEYhp0ZCUP_HAk",
        "qgberZ_GO_M0luD--6ICnKoJoNsGniGMl5bP0mt1KS8",
        "v_ufEM5Ozoub5HdXM6QzPoJefxzn6-9Jp-KYIvp5K78",
        "wkt-dqQ0QJi3Mbw9_1v4PSl5Tyluctzy0BPbPasX4lI"
    ],

    "age_equal_or_over": {
        "_sd": [
            "51F7iAPg_JZLYQOZzmInfVb7Dm4A7ItKjf0DzLaFuRg",
            "8ehSQCxHC90lQQvwPqJmlsE3aBsTLXfSFdABhG1r4oY",
            "XziOO_oHFXgJO6HYVClDMQorsAOMU9P-AUqB4Ab8J6o",
            "kvFx5InkYZJJ72tEwsG27fi3jBGoatsZiVd3vA0b7Ak",
            "lQYi2wOoTefTc4rK-9Cq2mKW2Onwulk-e08f2r7SqDE",
            "vh3-Wnego_RenqKkZ_Alnteo8TVU_9Z-IyfNzaRNoOg"
        ]
    },

    "address": {
        "_sd": [
            "Fc909lFNobvjDRO4JCkkcRS24PtkAxzRarxPVJ4GorY",
            "I-da3bVCY1n6Koam7K2NMjyvTo8plzfvGeytvt7OgeM",
            "NzSDBxiSqMaFdIH92g281e47aBB3c_AXEOmVRucd3zw",
            "dpha7BGCPK1ZQyL9rFiNuEdvvSnkpGYSXfbskeK9T-I",
            "jqepCG5AgZE2zoDo_MjEZbzToSMnwZ90Oo5_3bMuYEE"
        ]
    },

    "place_of_birth": {
        "_sd": [
            "RZbCkkoc5yDveqfCZYxJqJbIKySbvGzfVfY_vwi2Srs",
            "WqbCLRC31iMI67-sdGkdyd5-e7Y-2SdDM-NOrZQR3O0",
            "pEtPxpWa4yYISJR9Po74E6b0Ij_qsVxH3IPv4xzrFNo"
        ]
    },
    
    "cnf": {
        "jwk": {
            "kty": "EC",
            "crv": "P-256",
            "x": "52aDI_ur05n1f_p3jiYGUU82oKZr3m4LsAErM536crQ",
            "y": "ckhZ-KQ5aXNL91R8Eufg1aOf8Z5pZJnIvuCzNGfdnzo"
        }
    }
}

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might be nice, but can we please merge this PR as a starting point, and then do an additional PR to add examples. etc.?


Note: The `cnf` claim is used for expressing key binding in SD-JWT VCs.
The example above shows a public key in JWK format.

Note: Additional technical claims are not shown here, including
references to the issuer, validity status information, and more.

##### 2.5.3.2 Further stipulations

PID attributes in Table 1 SHALL be released only in a VP Token, as
specified in \[OpenID4VP\]. This means that these attributes SHALL be
Expand Down