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Fail closed on OpenID4VCI key proofs
1 parent c17df7b commit 1d77157

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Lines changed: 2053 additions & 167 deletions

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‎config/module_oidc.php.dist‎

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@@ -1636,6 +1636,45 @@ $config = [
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// ModuleConfig::OPTION_VCI_CREDENTIAL_TTLS => [
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// 'UniversityDegreeCredential' => 'P1Y', // 1 year
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// 'EmployeeBadgeCredential' => 'P90D', // 90 days
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// ],
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/**
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* (optional) Whether each credential configuration binds its credentials to
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* a key the wallet proves it holds. Configurations which are not listed
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* here are proof-bound, which is the default.
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*
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* VciCredentialBindingPolicyEnum::ProofBound (the default) requires the
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* Credential Request to carry a `proofs` parameter, verifies the key proof
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* inside it, and issues the credential to the holder identifier that proof
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* resolves to. The configuration advertises both
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* `cryptographic_binding_methods_supported` and `proof_types_supported`.
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*
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* VciCredentialBindingPolicyEnum::Proofless issues credentials which are
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* not bound to any wallet key, to a subject identifier derived from the
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* authenticated user. The configuration then advertises neither of those
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* two metadata fields, and a key proof sent anyway is refused - nothing
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* told the wallet which proof type or signing algorithm to build one with.
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*
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* OpenID4VCI ties these together, which is why one option governs the
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* advertisement and the issuance at once: `proof_types_supported` must be
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* present wherever `cryptographic_binding_methods_supported` is, and a
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* Credential Request must carry `proofs` wherever `proof_types_supported`
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* is. Advertising binding and then issuing without it tells a wallet its
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* credential is held to its key when nothing of the sort was checked.
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*
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* Note that a proofless configuration can not be conformant to profiles
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* which require holder binding, such as DIIP.
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*
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* This is a top-level option rather than something inside the credential
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* configurations, because those are published verbatim as Credential
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* Issuer metadata and anything placed among them becomes visible to every
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* wallet.
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*/
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// ModuleConfig::OPTION_VCI_CREDENTIAL_BINDING_POLICIES => [
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// 'UniversityDegreeCredential' =>
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// \SimpleSAML\Module\oidc\Codebooks\VciCredentialBindingPolicyEnum::ProofBound,
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// 'EmployeeBadgeCredential' =>
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// \SimpleSAML\Module\oidc\Codebooks\VciCredentialBindingPolicyEnum::Proofless,
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// ],
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/**

‎locales/en/LC_MESSAGES/oidc.po‎

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@@ -2246,3 +2246,24 @@ msgid ""
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"You will be presented with a Credential Offer which you can use to test "
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"credential issuance."
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msgstr ""
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msgid "Credential Binding Policies"
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msgstr ""
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msgid "Every configuration requires a key proof"
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msgstr ""
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msgid ""
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"Every credential configuration binds its credentials to a key the wallet "
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"proves it holds, which is the default. Each one advertises the binding "
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"methods and proof types it accepts, and a Credential Request carrying no "
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"valid key proof is refused."
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msgstr ""
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msgid ""
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"These credential configurations issue credentials which are not bound to "
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"any wallet key, so nothing ties an issued credential to whoever presents it "
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"later. They advertise no binding methods and no proof types, and a key "
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"proof sent to them is refused. Configurations which are not listed require "
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"a key proof."
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msgstr ""

‎locales/es/LC_MESSAGES/oidc.po‎

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@@ -2246,3 +2246,24 @@ msgid ""
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"You will be presented with a Credential Offer which you can use to test "
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"credential issuance."
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msgstr ""
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msgid "Credential Binding Policies"
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msgstr ""
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msgid "Every configuration requires a key proof"
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msgstr ""
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msgid ""
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"Every credential configuration binds its credentials to a key the wallet "
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"proves it holds, which is the default. Each one advertises the binding "
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"methods and proof types it accepts, and a Credential Request carrying no "
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"valid key proof is refused."
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msgstr ""
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msgid ""
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"These credential configurations issue credentials which are not bound to "
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"any wallet key, so nothing ties an issued credential to whoever presents it "
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"later. They advertise no binding methods and no proof types, and a key "
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"proof sent to them is refused. Configurations which are not listed require "
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"a key proof."
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msgstr ""

‎locales/fr/LC_MESSAGES/oidc.po‎

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@@ -2246,3 +2246,24 @@ msgid ""
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"You will be presented with a Credential Offer which you can use to test "
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"credential issuance."
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msgstr ""
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msgid "Credential Binding Policies"
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msgstr ""
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msgid "Every configuration requires a key proof"
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msgstr ""
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msgid ""
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"Every credential configuration binds its credentials to a key the wallet "
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"proves it holds, which is the default. Each one advertises the binding "
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"methods and proof types it accepts, and a Credential Request carrying no "
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"valid key proof is refused."
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msgstr ""
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msgid ""
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"These credential configurations issue credentials which are not bound to "
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"any wallet key, so nothing ties an issued credential to whoever presents it "
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"later. They advertise no binding methods and no proof types, and a key "
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"proof sent to them is refused. Configurations which are not listed require "
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"a key proof."
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msgstr ""

‎locales/hr/LC_MESSAGES/oidc.po‎

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@@ -2294,3 +2294,24 @@ msgid ""
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"You will be presented with a Credential Offer which you can use to test "
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"credential issuance."
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msgstr ""
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msgid "Credential Binding Policies"
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msgstr ""
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msgid "Every configuration requires a key proof"
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msgstr ""
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msgid ""
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"Every credential configuration binds its credentials to a key the wallet "
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"proves it holds, which is the default. Each one advertises the binding "
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"methods and proof types it accepts, and a Credential Request carrying no "
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"valid key proof is refused."
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msgstr ""
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msgid ""
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"These credential configurations issue credentials which are not bound to "
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"any wallet key, so nothing ties an issued credential to whoever presents it "
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"later. They advertise no binding methods and no proof types, and a key "
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"proof sent to them is refused. Configurations which are not listed require "
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"a key proof."
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msgstr ""

‎locales/it/LC_MESSAGES/oidc.po‎

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@@ -2246,3 +2246,24 @@ msgid ""
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"You will be presented with a Credential Offer which you can use to test "
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"credential issuance."
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msgstr ""
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msgid "Credential Binding Policies"
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msgstr ""
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msgid "Every configuration requires a key proof"
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msgstr ""
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msgid ""
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"Every credential configuration binds its credentials to a key the wallet "
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"proves it holds, which is the default. Each one advertises the binding "
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"methods and proof types it accepts, and a Credential Request carrying no "
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"valid key proof is refused."
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msgstr ""
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msgid ""
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"These credential configurations issue credentials which are not bound to "
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"any wallet key, so nothing ties an issued credential to whoever presents it "
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"later. They advertise no binding methods and no proof types, and a key "
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"proof sent to them is refused. Configurations which are not listed require "
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"a key proof."
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msgstr ""

‎locales/nl/LC_MESSAGES/oidc.po‎

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@@ -2200,3 +2200,24 @@ msgid ""
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"You will be presented with a Credential Offer which you can use to test "
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"credential issuance."
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msgstr ""
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msgid "Credential Binding Policies"
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msgstr ""
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msgid "Every configuration requires a key proof"
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msgstr ""
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msgid ""
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"Every credential configuration binds its credentials to a key the wallet "
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"proves it holds, which is the default. Each one advertises the binding "
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"methods and proof types it accepts, and a Credential Request carrying no "
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"valid key proof is refused."
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msgstr ""
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msgid ""
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"These credential configurations issue credentials which are not bound to "
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"any wallet key, so nothing ties an issued credential to whoever presents it "
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"later. They advertise no binding methods and no proof types, and a key "
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"proof sent to them is refused. Configurations which are not listed require "
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"a key proof."
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msgstr ""

‎routing/services/services.yml‎

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@@ -54,6 +54,12 @@ services:
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SimpleSAML\Module\oidc\StatusList\StatusListLifecycle:
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public: true
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# Verifiable Credential Issuance. Values carry what a validated request resolved to rather than being
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# autowired, so they are excluded the same way the Token Status List ones are.
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SimpleSAML\Module\oidc\VerifiableCredentials\:
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resource: '../../src/VerifiableCredentials/*'
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exclude: '../../src/VerifiableCredentials/{Values}'
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SimpleSAML\Module\oidc\Factories\:
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resource: '../../src/Factories/*'
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‎src/Admin/ConfigOverview/VciOverviewBuilder.php‎

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@@ -7,6 +7,7 @@
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use DateInterval;
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use SimpleSAML\Locale\Translate;
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use SimpleSAML\Module\oidc\Codebooks\ConfigOverviewValueTypeEnum;
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use SimpleSAML\Module\oidc\Codebooks\VciCredentialBindingPolicyEnum;
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use SimpleSAML\Module\oidc\ModuleConfig;
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use SimpleSAML\Module\oidc\StatusList\Values\StatusListPool;
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use SimpleSAML\Module\oidc\StatusList\Values\StatusListPoolBag;
@@ -557,6 +558,51 @@ protected function buildCredentialConfigurationsSection(): Section
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) : null,
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$error,
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),
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$this->guardRow(
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Translate::noop('Credential Binding Policies'),
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ModuleConfig::OPTION_VCI_CREDENTIAL_BINDING_POLICIES,
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function (): Row {
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// Only the exceptions are listed. Requiring a key proof is the default, so naming
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// every configuration which does would bury the ones which do not, and it is those
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// an administrator needs to recognise on sight.
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$proofless = array_keys(
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array_filter(
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$this->moduleConfig->getVciCredentialBindingPolicies(),
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$this->isProofless(...),
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),
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);
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if ($proofless === []) {
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return new Row(
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Translate::noop('Credential Binding Policies'),
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Translate::noop('Every configuration requires a key proof'),
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ConfigOverviewValueTypeEnum::Text,
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ModuleConfig::OPTION_VCI_CREDENTIAL_BINDING_POLICIES,
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Translate::noop(
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'Every credential configuration binds its credentials to a key the ' .
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'wallet proves it holds, which is the default. Each one advertises ' .
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'the binding methods and proof types it accepts, and a Credential ' .
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'Request carrying no valid key proof is refused.',
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),
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);
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}
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return new Row(
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Translate::noop('Credential Binding Policies'),
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$proofless,
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ConfigOverviewValueTypeEnum::StringList,
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ModuleConfig::OPTION_VCI_CREDENTIAL_BINDING_POLICIES,
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null,
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Translate::noop(
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'These credential configurations issue credentials which are not bound ' .
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'to any wallet key, so nothing ties an issued credential to whoever ' .
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'presents it later. They advertise no binding methods and no proof ' .
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'types, and a key proof sent to them is refused. Configurations which ' .
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'are not listed require a key proof.',
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),
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);
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},
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),
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new Row(
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Translate::noop('Attribute to Claim Path Mappings'),
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$attributeMap,
@@ -1007,6 +1053,15 @@ protected function normalizeRedirectUriPrefix(mixed $prefix): ?string
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}
10081054

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/**
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* Whether a credential configuration issues credentials which are not bound to a holder key.
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*/
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protected function isProofless(VciCredentialBindingPolicyEnum $bindingPolicy): bool
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{
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return $bindingPolicy === VciCredentialBindingPolicyEnum::Proofless;
1062+
}
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1064+
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/**
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* Whether any credential configuration declares a format which cannot be issued.
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*/

‎src/Codebooks/VciCredentialBindingPolicyEnum.php‎

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<?php
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declare(strict_types=1);
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namespace SimpleSAML\Module\oidc\Codebooks;
6+
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/**
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* Whether a credential configuration binds the credentials it issues to a key the wallet proves it holds.
9+
*
10+
* OpenID4VCI chains the two halves of this together: `proof_types_supported` must be present in a
11+
* credential configuration whenever `cryptographic_binding_methods_supported` is, and a Credential
12+
* Request must carry `proofs` whenever the configuration advertises `proof_types_supported`. So the
13+
* choice cannot be made per metadata field, and it cannot be made per request either -- it belongs to
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* the configuration, and it governs what is advertised and what is accepted at the same time.
15+
*
16+
* Advertising binding and then issuing without it, which is what this module did before, tells a wallet
17+
* the credential it received is held to its key when nothing of the sort was checked.
18+
*/
19+
enum VciCredentialBindingPolicyEnum: string
20+
{
21+
/**
22+
* The default. A Key Proof is required, verified, and the credential is issued to the holder
23+
* identifier that proof resolves to. Both binding metadata fields are advertised.
24+
*/
25+
case ProofBound = 'proof_bound';
26+
27+
/**
28+
* Credentials are issued unbound, to a subject identifier this issuer derives from the
29+
* authenticated user. Neither binding metadata field is advertised, and a Key Proof sent anyway is
30+
* refused: nothing told the wallet which proof type or signing algorithm to produce one with, so
31+
* accepting it would mean honouring a proof this configuration never asked for.
32+
*/
33+
case Proofless = 'proofless';
34+
}

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