Trust List validation

CHANGELOG.md

@@ -50,6 +50,10 @@ Release 6.0.0 (unreleased):
    - Update Bouncy Castle 1.84
    - Update to kotlinx.coroutines 1.11.0
  - Matrix testing
+ - Add `LoTEFilterService` for extracting trust list certificates from `LoTE` based on `ServiceTypeIdentifier`
+ - Add signature and time validity checks of certificate against the trust list
+ - Add JAdES B-B validation (Used when fetching LoTE)
+ - Add `issuer` property in `StoreEntry`, for evaluation of trust against trust list
 
 Release 5.12.0:
  - W3C JWT VC:

etsi-data-classes/src/commonMain/kotlin/at/asitplus/etsi/EtsiX509CertificateSerializer.kt

@@ -6,10 +6,15 @@ import kotlinx.serialization.KSerializer
 import kotlinx.serialization.SerialName
 import kotlinx.serialization.Serializable
 import kotlinx.serialization.descriptors.SerialDescriptor
+import kotlinx.serialization.descriptors.buildClassSerialDescriptor
 import kotlinx.serialization.encoding.Decoder
 import kotlinx.serialization.encoding.Encoder
+import kotlinx.serialization.json.JsonDecoder
+import kotlinx.serialization.json.jsonObject
+import kotlinx.serialization.json.jsonPrimitive
+import kotlin.io.encoding.Base64
 
-class EtsiX509CertificateSerializer : KSerializer<X509Certificate> {
+class EtsiX509CertificateSerializer : KSerializer<X509Certificate?> {
     private val delegate = EtsiX509CertificateSerializationSurrogate.serializer()
     override val descriptor: SerialDescriptor
         get() = SerialDescriptor(
@@ -19,8 +24,10 @@ class EtsiX509CertificateSerializer : KSerializer<X509Certificate> {
 
     override fun serialize(
         encoder: Encoder,
-        value: X509Certificate
+        value: X509Certificate?
     ) {
+        if (value == null) return encoder.encodeNull()
+
         encoder.encodeSerializableValue(
             EtsiX509CertificateSerializationSurrogate.serializer(),
             EtsiX509CertificateSerializationSurrogate(
@@ -29,9 +36,16 @@ class EtsiX509CertificateSerializer : KSerializer<X509Certificate> {
         )
     }
 
-    override fun deserialize(decoder: Decoder) = decoder.decodeSerializableValue(
-        EtsiX509CertificateSerializationSurrogate.serializer(),
-    ).value
+    override fun deserialize(decoder: Decoder): X509Certificate? = try {
+        if (decoder is JsonDecoder) {
+            val element = decoder.decodeJsonElement()
+            decoder.json.decodeFromJsonElement(delegate, element).value
+        } else {
+            decoder.decodeSerializableValue(delegate).value
+        }
+    } catch (_: Exception) {
+        null
+    }
 
     @Serializable
     private data class EtsiX509CertificateSerializationSurrogate(

etsi-data-classes/src/commonMain/kotlin/at/asitplus/etsi/ServiceDigitalIdentity.kt

@@ -22,7 +22,7 @@ interface OtherId
 @Serializable
 data class ServiceDigitalIdentity(
     @SerialName(SerialNames.X509_CERTIFICATE)
-    val x509Certificates: List<@Serializable(with = EtsiX509CertificateSerializer::class) X509Certificate>? = null,
+    val x509Certificates: List<@Serializable(with = EtsiX509CertificateSerializer::class) X509Certificate?> = emptyList(),
     @SerialName(SerialNames.X509_SUBJECT_NAMES)
     val x509SubjectNames: List<Rfc4514DistinguishedName>? = null,
     @SerialName(SerialNames.PUBLIC_KEY_VALUE)
@@ -33,18 +33,15 @@ data class ServiceDigitalIdentity(
     val otherIds: List<OtherId>? = null,
 ) {
     init {
-        require(x509Certificates?.isNotEmpty() != false) {
-            "Expected at least 1 X509Certificate, but got 0."
+        require( x509Certificates.isNotEmpty() || x509SKIs?.isNotEmpty() != false) {
+            "Expected at least 1 X509Certificate or at least 1 X509SKI, but got 0."
         }
         require(x509SubjectNames?.isNotEmpty() != false) {
             "Expected at least 1 X509SubjectName, but got 0."
         }
         require(publicKeyValues?.isNotEmpty() != false) {
             "Expected at least 1 PublicKeyValue, but got 0."
         }
-        require(x509SKIs?.isNotEmpty() != false) {
-            "Expected at least 1 X509SKI, but got 0."
-        }
         require(otherIds?.isNotEmpty() != false) {
             "Expected at least 1 other id, but got 0."
         }

etsi-data-classes/src/commonMain/kotlin/at/asitplus/etsi/TrustListPayload.kt

@@ -0,0 +1,10 @@
+package at.asitplus.etsi
+
+import kotlinx.serialization.SerialName
+import kotlinx.serialization.Serializable
+
+@Serializable
+data class TrustListPayload(
+    @SerialName("LoTE")
+    val loTe: ListOfTrustedEntities
+)

vck/build.gradle.kts

@@ -29,6 +29,7 @@ kotlin {
             dependencies {
                 api(project(":dif-data-classes"))
                 api(project(":openid-data-classes"))
+                api(project(":etsi-data-classes"))
                 api(project(":sd-jwt-type-metadata"))
                 commonImplementationAndApiDependencies()
             }

vck/src/commonMain/kotlin/at/asitplus/wallet/lib/agent/HolderAgent.kt

@@ -15,6 +15,7 @@ import at.asitplus.openid.dcql.DCQLQuery
 import at.asitplus.signum.indispensable.cosef.CoseKey
 import at.asitplus.signum.indispensable.cosef.toCoseKey
 import at.asitplus.signum.indispensable.pki.X509Certificate
+import at.asitplus.signum.indispensable.pki.leaf
 import at.asitplus.wallet.lib.agent.SubjectCredentialStore.StoreEntry
 import at.asitplus.wallet.lib.data.CredentialPresentation
 import at.asitplus.wallet.lib.data.CredentialPresentationRequest
@@ -68,7 +69,8 @@ class HolderAgent(
                     vc = validated.jws,
                     vcSerialized = credential.vcJws,
                     scheme = credential.scheme,
-                    renewalInfo = renewalInfo
+                    renewalInfo = renewalInfo,
+                    issuer = credential.signedVcJws.jws.jwsHeader.certificateChain?.leaf?.encodeToDerOrNull()
                 )
             }
 
@@ -82,7 +84,8 @@ class HolderAgent(
                     vcSerialized = credential.vcSdJwt,
                     disclosures = validated.disclosures,
                     scheme = credential.scheme,
-                    renewalInfo = renewalInfo
+                    renewalInfo = renewalInfo,
+                    issuer = credential.signedSdJwtVc.jws.jwsHeader.certificateChain?.leaf?.encodeToDerOrNull()
                 )
             }
 
@@ -92,7 +95,8 @@ class HolderAgent(
                 subjectCredentialStore.storeCredential(
                     issuerSigned = validated.issuerSigned,
                     scheme = credential.scheme,
-                    renewalInfo = renewalInfo
+                    renewalInfo = renewalInfo,
+                    issuer = credential.issuerSigned.issuerAuth.unprotectedHeader?.certificateChain?.getOrNull(0)
                 )
             }
         }

vck/src/commonMain/kotlin/at/asitplus/wallet/lib/agent/InMemorySubjectCredentialStore.kt

@@ -17,6 +17,7 @@ class InMemorySubjectCredentialStore : SubjectCredentialStore {
         vcSerialized: String,
         scheme: ConstantIndex.CredentialScheme,
         renewalInfo: CredentialRenewalInfo?,
+        issuer: ByteArray?
     ) = SubjectCredentialStore.StoreEntry.Vc(vcSerialized, vc, scheme.schemaUri, renewalInfo)
         .also { credentials += it }
 
@@ -26,13 +27,15 @@ class InMemorySubjectCredentialStore : SubjectCredentialStore {
         disclosures: Map<String, SelectiveDisclosureItem?>,
         scheme: ConstantIndex.CredentialScheme,
         renewalInfo: CredentialRenewalInfo?,
+        issuer: ByteArray?
     ) = SubjectCredentialStore.StoreEntry.SdJwt(vcSerialized, vc, disclosures, scheme.schemaUri, renewalInfo)
         .also { credentials += it }
 
     override suspend fun storeCredential(
         issuerSigned: IssuerSigned,
         scheme: ConstantIndex.CredentialScheme,
         renewalInfo: CredentialRenewalInfo?,
+        issuer: ByteArray?
     ) = SubjectCredentialStore.StoreEntry.Iso(issuerSigned, scheme.schemaUri, renewalInfo)
         .also { credentials += it }
 

vck/src/commonMain/kotlin/at/asitplus/wallet/lib/agent/SubjectCredentialStore.kt

@@ -11,6 +11,7 @@ import at.asitplus.openid.OAuth2AuthorizationServerMetadata
 import at.asitplus.openid.SupportedCredentialFormat
 import at.asitplus.signum.indispensable.cosef.io.coseCompliantSerializer
 import at.asitplus.signum.indispensable.josef.io.joseCompliantSerializer
+import at.asitplus.signum.indispensable.pki.X509Certificate
 import at.asitplus.wallet.lib.data.AttributeIndex
 import at.asitplus.wallet.lib.data.ConstantIndex
 import at.asitplus.wallet.lib.data.IsoMdocFallbackCredentialScheme
@@ -43,6 +44,7 @@ interface SubjectCredentialStore {
         vcSerialized: String,
         scheme: ConstantIndex.CredentialScheme,
         renewalInfo: CredentialRenewalInfo? = null,
+        issuer: ByteArray? = null
     ): StoreEntry
 
     /**
@@ -58,6 +60,7 @@ interface SubjectCredentialStore {
         disclosures: Map<String, SelectiveDisclosureItem?>,
         scheme: ConstantIndex.CredentialScheme,
         renewalInfo: CredentialRenewalInfo? = null,
+        issuer: ByteArray? = null
     ): StoreEntry
 
     /**
@@ -70,6 +73,7 @@ interface SubjectCredentialStore {
         issuerSigned: IssuerSigned,
         scheme: ConstantIndex.CredentialScheme,
         renewalInfo: CredentialRenewalInfo? = null,
+        issuer: ByteArray? = null
     ): StoreEntry
 
     /**
@@ -87,6 +91,7 @@ interface SubjectCredentialStore {
         val credentialFormat: CredentialFormatEnum
         val claimFormat: ClaimFormat
         val renewalInfo: CredentialRenewalInfo?
+        val issuer: ByteArray?
 
         fun getFallbackScheme(): ConstantIndex.CredentialScheme?
 
@@ -100,6 +105,8 @@ interface SubjectCredentialStore {
             override val schemaUri: String,
             @SerialName("credential-renewal-info")
             override val renewalInfo: CredentialRenewalInfo? = null,
+            @SerialName("issuer")
+            override val issuer: ByteArray? = null,
         ) : StoreEntry {
             override fun getFallbackScheme(): ConstantIndex.CredentialScheme =
                 VcFallbackCredentialScheme(vc.vc.type.first { it != VERIFIABLE_CREDENTIAL })
@@ -121,6 +128,8 @@ interface SubjectCredentialStore {
             override val schemaUri: String,
             @SerialName("credential-renewal-info")
             override val renewalInfo: CredentialRenewalInfo? = null,
+            @SerialName("issuer")
+            override val issuer: ByteArray? = null
         ) : StoreEntry {
             override fun getFallbackScheme(): ConstantIndex.CredentialScheme =
                 SdJwtFallbackCredentialScheme(sdJwt.verifiableCredentialType)
@@ -137,6 +146,8 @@ interface SubjectCredentialStore {
             override val schemaUri: String,
             @SerialName("credential-renewal-info")
             override val renewalInfo: CredentialRenewalInfo? = null,
+            @SerialName("issuer")
+            override val issuer: ByteArray? = null
         ) : StoreEntry {
             override fun getFallbackScheme(): ConstantIndex.CredentialScheme? = catchingUnwrapped {
                 IsoMdocFallbackCredentialScheme(issuerSigned.issuerAuth.payload?.docType!!)
@@ -171,4 +182,4 @@ data class CredentialRenewalInfo(
     val oauthMetadata: OAuth2AuthorizationServerMetadata,
     val credentialFormat: SupportedCredentialFormat,
     val credentialIdentifier: String,
-)
+)

vck/src/commonMain/kotlin/at/asitplus/wallet/lib/etsi/LoTEFilterService.kt

@@ -0,0 +1,52 @@
+package at.asitplus.wallet.lib.etsi
+
+import at.asitplus.etsi.EtsiX509CertificateSerializer
+import at.asitplus.etsi.ListOfTrustedEntities
+import at.asitplus.etsi.TEName
+import at.asitplus.signum.indispensable.asn1.Asn1Primitive
+import at.asitplus.signum.indispensable.asn1.Asn1String
+import at.asitplus.signum.indispensable.pki.AttributeTypeAndValue
+import at.asitplus.signum.indispensable.pki.X509Certificate
+import kotlinx.serialization.Serializable
+
+class LoTEFilterService {
+
+    fun extractTrustedCertificates(lote: ListOfTrustedEntities, criteria: LoTEFilterCriteria): List<TrustedCertificate> {
+        val entities = lote.trustedEntitiesList ?: return emptyList()
+
+        return entities.flatMap { entity ->
+            val providerName = entity.trustedEntityInformation.teName
+
+            entity.trustedEntityServices
+                .filter { it.serviceInformation.serviceTypeIdentifier?.string == criteria.expectedServiceType }
+                .flatMap { service -> service.serviceInformation.serviceDigitalIdentity.x509Certificates }
+                .filter { cert -> cert?.hasMatchingOrganization(providerName) == true }
+                .map { cert -> TrustedCertificate(cert, providerName, criteria.expectedServiceType) }
+        }
+    }
+
+    // Checks if any organization name matches the provider's TEName
+    private fun X509Certificate.hasMatchingOrganization(providerName: TEName): Boolean {
+        val orgName = tbsCertificate.subjectName
+            .flatMap { it.attrsAndValues }
+            .filterIsInstance<AttributeTypeAndValue.Organization>()
+            .firstOrNull()
+            ?.asStringOrNull() ?: return false
+
+        return providerName.any { it.value.equals(orgName, ignoreCase = true) }
+    }
+    private fun AttributeTypeAndValue.Organization.asStringOrNull(): String? = when (val element = value) {
+        is Asn1Primitive -> runCatching { Asn1String.decodeFromTlv(element).value }.getOrNull()
+        else -> element.toString()
+    }
+}
+
+data class TrustedCertificate(
+    val certificate: @Serializable(with = EtsiX509CertificateSerializer::class) X509Certificate?,
+    val providerName: TEName,
+    val serviceType: String
+)
+
+data class LoTEFilterCriteria(
+    val expectedServiceType: String,
+)

vck/src/commonMain/kotlin/at/asitplus/wallet/lib/etsi/TrustListValidator.kt

@@ -0,0 +1,67 @@
+package at.asitplus.wallet.lib.etsi
+
+import at.asitplus.KmmResult
+import at.asitplus.catching
+import at.asitplus.signum.indispensable.X509SignatureAlgorithm
+import at.asitplus.signum.indispensable.pki.CertificateChain
+import at.asitplus.signum.indispensable.pki.X509Certificate
+import at.asitplus.signum.supreme.sign.verifierFor
+import at.asitplus.signum.supreme.sign.verify
+import kotlin.time.Clock
+import kotlin.time.Instant
+
+/**
+ * Verifies if this certificate is directly signed and trusted by any anchor in the [trustStore].
+ * Enforces time validity, cryptographic integrity
+ */
+fun X509Certificate.isTrustedBy(
+    trustStore: CertificateChain,
+    date: Instant = Clock.System.now()
+): KmmResult<Unit> = catching {
+    if (!this.isValidAt(date)) throw Exception("Certificate is not valid at $date")
+
+    trustStore
+        .asSequence()
+        .filter { it.isValidAt(date) }
+        .map { it.isIssuerOf(this) }
+        .firstOrNull { it.isSuccess }
+        ?: throw IllegalArgumentException(
+            "No valid trust anchor could verify certificate"
+        )
+
+}
+
+/**
+ * Checks whether this certificate has expired at the specified [date].
+ * @return `true` if the certificate is expired, `false` otherwise.
+ */
+fun X509Certificate.isExpired(date: Instant = Clock.System.now()): Boolean =
+    Instant.fromEpochSeconds(date.epochSeconds) > tbsCertificate.validUntil.instant
+
+/**
+ * Checks whether this certificate is not yet valid at the specified [date].
+ * @return `true` if the certificate is not yet valid, `false` otherwise.
+ */
+fun X509Certificate.isNotYetValid(date: Instant = Clock.System.now()): Boolean =
+    Instant.fromEpochSeconds(date.epochSeconds) < tbsCertificate.validFrom.instant
+
+
+/**
+ * Checks whether this certificate is valid at the specified [date].
+ */
+fun X509Certificate.isValidAt(date: Instant = Clock.System.now()): Boolean = !(isExpired(date) || isNotYetValid(date))
+
+/**
+ * Verifies that this certificate is the issuer of the given [cert].
+ */
+fun X509Certificate.isIssuerOf(cert: X509Certificate): KmmResult<Unit> = catching {
+    if (cert.tbsCertificate.issuerName != this.tbsCertificate.subjectName) throw Exception("Subject of issuer cert and issuer of child certificate mismatch.")
+
+    if (cert.tbsCertificate.issuerUniqueID != this.tbsCertificate.subjectUniqueID) throw Exception("UID of issuer cert and UID of issuer in child certificate mismatch.")
+
+    val verifier = (cert.signatureAlgorithm as X509SignatureAlgorithm).verifierFor(this.decodedPublicKey.getOrThrow()).getOrThrow()
+    verifier.verify(
+        cert.tbsCertificate.encodeToDer(),
+        cert.decodedSignature.getOrThrow()
+    ).getOrThrow()
+}