General Properties¶

The objectives include:

• Ensuring that the Wallet Instance maintains a level of integrity that is capable of preventing any manipulation or forgery attempts by unauthorized third parties.

• Having the Wallet Provider issue a certificate of conformity to assure that the previously mentioned security and trust objectives are fulfilled.

To meet these requirements, it is necessary for each Wallet Instance to issue an attestation of conformity, guaranteeing its security and compliance with the Trust Model.

This verifiable attestation, called Wallet Instance Attestation, must be electronically signed by its issuer.

Requirements¶

The following requirements are assumed for the Wallet Instance Attestation:

1. Efficiency: The Wallet Instance Attestation should use an efficient format like JSON Web Token (JWT) for light and fast data management, and compliance with various formats used for eudiw solutions.

2. Simplicity: The Wallet Provider should be based on a REST architecture for issuing Wallet Instance Attestations.

3. Public key holder binding: The Wallet Instance Attestation must be securely linked to the Wallet Instance public key.

4. Issued and signed by an accredited Wallet Provider: The Wallet Instance Attestation must be issued and signed by an accredited and reliable Wallet Provider, thereby providing integrity and authenticity to the attestation.

5. Authenticity/Genuineness of the Wallet Instance: The Wallet Instance Attestation must ensure the integrity and authenticity of the Wallet Instance, verifying that it was accurately created and provided by the Wallet Provider. ⚠️

6. Ability to request multiple claims for several public keys: Each Wallet Instance should be able to request multiple attestations for different public keys associated with it. This requirement provides a privacy-preserving measure, as the public key could be used as a tracking tool in the credentials’ disclosure phase (also see point 10 below).

7. Reusability: The Wallet Instance Attestation should be usable multiple times during the validity period of the attestation, allowing for repeated authentication and authorization without the need to request new attestations with each interaction.

8. Expiration: The Wallet Instance Attestation should have a well-defined expiration date, after which it will no longer be considered valid, thereby ensuring the security and updating of attestations over time.

9. Revocation in case of loss/deletion of the private key: If the private key associated with the Wallet Instance is lost or deleted, the attestation automatically becomes invalid to prevent unauthorized use of the Wallet Instance. ⚠️

10. Pseudonymisation: The attestations are designed to be pseudonymised (i.e., they do not contain direct references to the person, making it impossible to identify them in the absence of additional information - see art. 4(5) GDPR for a comprehensive definition). Without such a measure, the use of the attestation on multiple RPs would pose a significant risk, as it would theoretically allow the RPs to merge databases and track Users. This requirement enhances the measures adopted according to

art. 32 GDPR.

High-end design¶

Static view of the components¶

Dynamic view of the components¶

This section describes the format of the Wallet Instance Attestation and how it is issued by the Wallet Provider.

• Message 1: The User initializes the Wallet Instance. In particular, this process happens after the Wallet Instance installation and after the expiration of the Wallet Instance Attestation is launched and every time the User wants to request or present a credential.

• Message 2-3: The Wallet Instance obtains metadata about its Wallet Provider. Among these, we also find the list of supported algorithms, public keys, endpoints.

• Message 4: The Wallet Instance verifies that the Wallet Provider is trustworthy by resolving the provider's trust chain up to the Trust Anchor.

• Message 5-7: The Wallet Instance creates a new key pair and requests a nonce from the Wallet Provider (as a measure against replay attacks).

• Message 8: The Wallet Instance generates a Wallet Instance Attestation Request, in JWS format, signed with the private key associated with the public key for which it wants to obtain the attestation.

• Message 9-13: The Wallet Instance sends the Wallet Instance Attestation Request to the Wallet Provider which verifies its validity and issues the signed attestation.

• Message 13-14:The Wallet Instance receives the Wallet Instance Attestation signed by the Wallet Provider and proceeds with a formal verification.

• Message 15:The Wallet Instance Attestation is ready to be consumed.

Detail design¶

We will go into the detail design below.

{
  "alg": "ES256",
  "kid": "5t5YYpBhN-EgIEEI5iUzr6r0MR02LnVQ0OmekmNKcjY",
  "typ": "entity-statement+jwt"
}
.
{
"iss": "https://wallet-provider.example.org",
"sub": "https://wallet-provider.example.org",
"jwks": {
  "keys": [
    {
      "crv": "P-256",
      "kty": "EC",
      "x": "qrJrj3Af_B57sbOIRrcBM7br7wOc8ynj7lHFPTeffUk",
      "y": "1H0cWDyGgvU8w-kPKU_xycOCUNT2o0bwslIQtnPU6iM",
      "kid": "5t5YYpBhN-EgIEEI5iUzr6r0MR02LnVQ0OmekmNKcjY"
    }
  ]
},
"metadata": {
  "eudi_wallet_provider": {
    "jwks": {
      "keys": [
        {
          "crv": "P-256",
          "kty": "EC",
          "x": "qrJrj3Af_B57sbOIRrcBM7br7wOc8ynj7lHFPTeffUk",
          "y": "1H0cWDyGgvU8w-kPKU_xycOCUNT2o0bwslIQtnPU6iM",
          "kid": "5t5YYpBhN-EgIEEI5iUzr6r0MR02LnVQ0OmekmNKcjY"
        }
      ]
    },
    "token_endpoint": "https://wallet-provider.example.org/token",
    "asc_values_supported": [
      "https://wallet-provider.example.org/LoA/basic",
      "https://wallet-provider.example.org/LoA/medium",
      "https://wallet-provider.example.org/LoA/high"
    ],
    "grant_types_supported": [
      "urn:ietf:params:oauth:client-assertion-type:jwt-key-attestation"
    ],
    "token_endpoint_auth_methods_supported": [
      "private_key_jwt"
    ],
    "token_endpoint_auth_signing_alg_values_supported": [
      "ES256",
      "ES384",
      "ES512"
    ]
  },
  "federation_entity": {
    "organization_name": "PagoPa S.p.A.",
    "homepage_uri": "https://wallet-provider.example.org",
    "policy_uri": "https://wallet-provider.example.org/privacy_policy",
    "tos_uri": "https://wallet-provider.example.org/info_policy",
    "logo_uri": "https://wallet-provider.example.org/logo.svg"
  }
},
"iat": 1687171759,
"exp": 1709290159
}

{
  "alg": "ES256",
  "kid": "vbeXJksM45xphtANnCiG6mCyuU4jfGNzopGuKvogg9c",
  "typ": "var+jwt"
}
.
{
  "iss": "vbeXJksM45xphtANnCiG6mCyuU4jfGNzopGuKvogg9c",
  "sub": "https://wallet-provider.example.org",
  "jti": "6ec69324-60a8-4e5b-a697-a766d85790ea",
  "type": "WalletInstanceAttestationRequest",
  "cnf": {
    "jwk": {
      "crv": "P-256",
      "kty": "EC",
      "x": "4HNptI-xr2pjyRJKGMnz4WmdnQD_uJSq4R95Nj98b44",
      "y": "LIZnSB39vFJhYgS3k7jXE4r3-CoGFQwZtPBIRqpNlrg",
      "kid": "vbeXJksM45xphtANnCiG6mCyuU4jfGNzopGuKvogg9c"
    }
  },
  "iat": 1686645115,
  "exp": 1686652315
}

{
  "alg": "ES256",
  "kid": "5t5YYpBhN-EgIEEI5iUzr6r0MR02LnVQ0OmekmNKcjY",
  "trust_chain": [
    "eyJhbGciOiJFUz...6S0A",
    "eyJhbGciOiJFUz...jJLA",
    "eyJhbGciOiJFUz...H9gw",
  ],
  "typ": "va+jwt",
  "x5c": ["MIIBjDCC ... XFehgKQA=="]
}
.
{
  "iss": "https://wallet-provider.example.org",
  "sub": "vbeXJksM45xphtANnCiG6mCyuU4jfGNzopGuKvogg9c",
  "type": "WalletInstanceAttestation",
  "policy_uri": "https://wallet-provider.example.org/privacy_policy",
  "tos_uri": "https://wallet-provider.example.org/info_policy",
  "logo_uri": "https://wallet-provider.example.org/logo.svg",
  "asc": "https://wallet-provider.example.org/LoA/basic",
  "cnf":
  {
    "jwk":
    {
      "crv": "P-256",
      "kty": "EC",
      "x": "4HNptI-xr2pjyRJKGMnz4WmdnQD_uJSq4R95Nj98b44",
      "y": "LIZnSB39vFJhYgS3k7jXE4r3-CoGFQwZtPBIRqpNlrg",
      "kid": "vbeXJksM45xphtANnCiG6mCyuU4jfGNzopGuKvogg9c"
    }
  },
  "authorization_endpoint": "eudiw:",
  "response_types_supported": [
    "vp_token"
  ],
  "vp_formats_supported": {
    "jwt_vp_json": {
      "alg_values_supported": ["ES256"]
    },
    "jwt_vc_json": {
      "alg_values_supported": ["ES256"]
    }
  },
  "request_object_signing_alg_values_supported": [
    "ES256"
  ],
  "presentation_definition_uri_supported": false,
  "iat": 1687281195,
  "exp": 1687288395
}