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[OID4VCI] Implement Key-Binding for jwt-credentials and fix it for SD-JWT #49895

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Merged
mposolda merged 6 commits into from
Jul 24, 2026
Merged

[OID4VCI] Implement Key-Binding for jwt-credentials and fix it for SD-JWT #49895

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a1ad235
implement key-binding for jwt-credentials
wistefan Jun 10, 2026
e65afad
fix sdjwt build to let cnf survive default decoy generation
wistefan Jun 11, 2026
43931d8
apply spotless
wistefan Jun 11, 2026
6876156
Update services/src/main/java/org/keycloak/protocol/oid4vc/issuance/c…
wistefan Jun 16, 2026
a898b0e
remove whitespaces
wistefan Jun 16, 2026
770253f
Potential fix for pull request finding
wistefan Jun 29, 2026
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25 changes: 15 additions & 10 deletions core/src/main/java/org/keycloak/sdjwt/SdJwt.java
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Expand Up @@ -252,16 +252,21 @@ public Builder withUseDefaultDecoys(boolean useDefaultDecoys) {
}

public SdJwt build() {
int numberOfDecoys = Optional.ofNullable(issuerSignedJwt.getDecoyClaims()).map(List::size).orElse(0);
if (useDefaultDecoys && numberOfDecoys == 0) {
List<DecoyClaim> decoyClaims = new ArrayList<>();
for (int i = 0; i < DEFAULT_NUMBER_OF_DECOYS; i++) {
decoyClaims.add(DecoyClaim.builder().build());
}
issuerSignedJwt.setDisclosureClaims(issuerSignedJwt.getDisclosureSpec(),
issuerSignedJwt.getDisclosureClaims(),
decoyClaims);
}
List<DecoyClaim> decoyClaims = Optional.ofNullable(issuerSignedJwt.getDecoyClaims())
.filter(list -> !list.isEmpty())
.orElseGet(() -> {
if (!useDefaultDecoys) {
return Collections.emptyList();
}
List<DecoyClaim> defaults = new ArrayList<>();
for (int i = 0; i < DEFAULT_NUMBER_OF_DECOYS; i++) {
defaults.add(DecoyClaim.builder().build());
}
return defaults;
});
issuerSignedJwt.setDisclosureClaims(issuerSignedJwt.getDisclosureSpec(),
issuerSignedJwt.getDisclosureClaims(),
decoyClaims);

SdJwt sdJwt = new SdJwt(issuerSignedJwt, keyBindingJWT, nestedSdJwts);
AtomicInteger signCounter = new AtomicInteger(0);
Expand Down
26 changes: 18 additions & 8 deletions .../main/java/org/keycloak/protocol/oid4vc/issuance/credentialbuilder/JwtCredentialBody.java
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Expand Up @@ -17,30 +17,40 @@

package org.keycloak.protocol.oid4vc.issuance.credentialbuilder;

import java.util.Map;

import org.keycloak.crypto.SignatureSignerContext;
import org.keycloak.jose.jwk.JWK;
import org.keycloak.jose.jws.JWSBuilder;
import org.keycloak.representations.JsonWebToken;
import org.keycloak.util.JsonSerialization;

import org.jboss.logging.Logger;
import static org.keycloak.OID4VCConstants.CLAIM_NAME_CNF;
import static org.keycloak.OID4VCConstants.CLAIM_NAME_JWK;

/**
* @author <a href="mailto:Ingrid.Kamga@adorsys.com">Ingrid Kamga</a>
*/
public class JwtCredentialBody implements CredentialBody {

private static final Logger LOGGER = Logger.getLogger(JwtCredentialBody.class);

private final JWSBuilder.EncodingBuilder jwsEncodingBuilder;
private final JWSBuilder jwsBuilder;
private final JsonWebToken jsonWebToken;

public JwtCredentialBody(JWSBuilder.EncodingBuilder jwsEncodingBuilder) {
this.jwsEncodingBuilder = jwsEncodingBuilder;
public JwtCredentialBody(JWSBuilder jwsBuilder, JsonWebToken jsonWebToken) {
this.jwsBuilder = jwsBuilder;
this.jsonWebToken = jsonWebToken;
}

@Override
public void addKeyBinding(JWK jwk) throws CredentialBuilderException {
LOGGER.warnf("Key binding is not yet implemented for JWT credentials");
Map<String, Object> jwkMap = JsonSerialization
.mapper
.convertValue(jwk, JsonSerialization.mapper.getTypeFactory()
.constructMapType(Map.class, String.class, Object.class));
jsonWebToken.setOtherClaims(CLAIM_NAME_CNF, Map.of(CLAIM_NAME_JWK, jwkMap));
}

public String sign(SignatureSignerContext signatureSignerContext) {
return jwsEncodingBuilder.sign(signatureSignerContext);
return jwsBuilder.jsonContent(jsonWebToken).sign(signatureSignerContext);
}
}
7 changes: 3 additions & 4 deletions ...in/java/org/keycloak/protocol/oid4vc/issuance/credentialbuilder/JwtCredentialBuilder.java
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Expand Up @@ -105,11 +105,10 @@ public JwtCredentialBody buildCredentialBody(
.map(Object::toString)
.ifPresent(jsonWebToken::subject);

JWSBuilder.EncodingBuilder jwsBuilder = new JWSBuilder()
.type(credentialBuildConfig.getTokenJwsType())
.jsonContent(jsonWebToken);
JWSBuilder jwsBuilder = new JWSBuilder()
.type(credentialBuildConfig.getTokenJwsType());

return new JwtCredentialBody(jwsBuilder);
return new JwtCredentialBody(jwsBuilder, jsonWebToken);
}

private static List<String> getCredentialTypes(List<String> credentialTypes) {
Expand Down
7 changes: 6 additions & 1 deletion ...ain/java/org/keycloak/protocol/oid4vc/issuance/credentialbuilder/SdJwtCredentialBody.java
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Expand Up @@ -21,6 +21,8 @@
import org.keycloak.jose.jwk.JWK;
import org.keycloak.sdjwt.IssuerSignedJWT;
import org.keycloak.sdjwt.SdJwt;
import org.keycloak.sdjwt.SdJwtClaimName;
import org.keycloak.sdjwt.VisibleSdJwtClaim;
import org.keycloak.util.JsonSerialization;

import com.fasterxml.jackson.databind.node.ObjectNode;
Expand All @@ -45,7 +47,10 @@ public void addKeyBinding(JWK jwk) throws CredentialBuilderException {
ObjectNode jwkNode = JsonSerialization.mapper.convertValue(jwk, ObjectNode.class);
ObjectNode keyBindingNode = JsonSerialization.mapper.createObjectNode();
keyBindingNode.set(CLAIM_NAME_JWK, jwkNode);
issuerSignedJWT.getPayload().set(CLAIM_NAME_CNF, keyBindingNode);

SdJwtClaimName cnfName = SdJwtClaimName.of(CLAIM_NAME_CNF);
issuerSignedJWT.getDisclosureClaims().removeIf(claim -> claim != null && cnfName.equals(claim.getClaimName()));
issuerSignedJWT.getDisclosureClaims().add(new VisibleSdJwtClaim(cnfName, keyBindingNode));
}

public IssuerSignedJWT getIssuerSignedJWT() {
Expand Down
42 changes: 42 additions & 0 deletions ...t/java/org/keycloak/tests/oid4vc/issuance/credentialbuilder/JwtCredentialBuilderTest.java
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Expand Up @@ -17,13 +17,16 @@

package org.keycloak.tests.oid4vc.issuance.credentialbuilder;

import java.security.KeyPairGenerator;
import java.time.Instant;
import java.time.temporal.ChronoUnit;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.UUID;

import org.keycloak.jose.jwk.JWK;
import org.keycloak.jose.jwk.JWKBuilder;
import org.keycloak.jose.jws.JWSInput;
import org.keycloak.jose.jws.JWSInputException;
import org.keycloak.protocol.oid4vc.issuance.TimeProvider;
Expand All @@ -38,9 +41,13 @@
import com.fasterxml.jackson.databind.JsonNode;
import org.junit.jupiter.api.Test;

import static org.keycloak.OID4VCConstants.CLAIM_NAME_CNF;
import static org.keycloak.OID4VCConstants.CLAIM_NAME_JWK;
import static org.keycloak.OID4VCConstants.CREDENTIAL_SUBJECT;

import static org.junit.jupiter.api.Assertions.assertEquals;
import static org.junit.jupiter.api.Assertions.assertNotNull;
import static org.junit.jupiter.api.Assertions.assertTrue;

/**
* @author <a href="mailto:Ingrid.Kamga@adorsys.com">Ingrid Kamga</a>
Expand Down Expand Up @@ -111,6 +118,41 @@ public void buildJwtCredential_AddsVerifiableCredentialType() throws Exception {
assertEquals("oid4vc_natural_person", credentialTypes.get(1).asText());
}

@Test
public void shouldBindHolderKeyWithCnfClaim() throws Exception {
VerifiableCredential verifiableCredential = getTestCredential(exampleCredentialClaims());
CredentialBuildConfig credentialBuildConfig = new CredentialBuildConfig().setTokenJwsType("JWT");

// Build credential body
JwtCredentialBody jwtCredentialBody = builder
.buildCredentialBody(verifiableCredential, credentialBuildConfig);

// Generate a holder key and bind it
var holderKeyPair = KeyPairGenerator.getInstance("RSA").generateKeyPair();
JWK holderJwk = JWKBuilder.create().kid("holder-key-1").rs256(holderKeyPair.getPublic());
jwtCredentialBody.addKeyBinding(holderJwk);

// Sign and parse JWS string
String jws = jwtCredentialBody.sign(exampleSigner());
JWSInput jwsInput = new JWSInput(jws);
JsonNode payload = jwsInput.readJsonContent(JsonNode.class);

// Assert cnf claim is present and contains the holder's JWK
JsonNode cnfNode = payload.get(CLAIM_NAME_CNF);
assertNotNull(cnfNode, "The cnf claim must be present in the JWT payload");

JsonNode jwkNode = cnfNode.get(CLAIM_NAME_JWK);
assertNotNull(jwkNode, "The cnf claim must contain a jwk field");
assertEquals("holder-key-1", jwkNode.get("kid").asText(),
"The bound JWK must have the holder's key ID");
assertTrue(jwkNode.has("n"), "The bound JWK must contain the RSA modulus");
assertTrue(jwkNode.has("e"), "The bound JWK must contain the RSA exponent");

// Verify the rest of the credential is intact
JsonNode credentialSubject = payload.get("vc").get(CREDENTIAL_SUBJECT);
assertEquals("randomValue", credentialSubject.get("randomKey").asText());
}

private JsonNode parseCredentialSubject(JWSInput jwsInput) throws JWSInputException {
JsonNode payload = jwsInput.readJsonContent(JsonNode.class);
return payload.get("vc").get(CREDENTIAL_SUBJECT);
Expand Down
53 changes: 52 additions & 1 deletion ...java/org/keycloak/tests/oid4vc/issuance/credentialbuilder/SdJwtCredentialBuilderTest.java
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Expand Up @@ -17,12 +17,17 @@

package org.keycloak.tests.oid4vc.issuance.credentialbuilder;

import java.security.KeyPairGenerator;
import java.util.List;
import java.util.Map;
import java.util.UUID;
import java.util.stream.Stream;

import org.keycloak.OID4VCConstants;
import org.keycloak.VCFormat;
import org.keycloak.common.VerificationException;
import org.keycloak.jose.jwk.JWK;
import org.keycloak.jose.jwk.JWKBuilder;
import org.keycloak.protocol.oid4vc.issuance.credentialbuilder.SdJwtCredentialBody;
import org.keycloak.protocol.oid4vc.issuance.credentialbuilder.SdJwtCredentialBuilder;
import org.keycloak.protocol.oid4vc.model.CredentialBuildConfig;
Expand All @@ -34,15 +39,21 @@
import org.keycloak.testframework.annotations.KeycloakIntegrationTest;
import org.keycloak.tests.oid4vc.OID4VCIssuerTestBase;

import com.fasterxml.jackson.databind.JsonNode;
import com.fasterxml.jackson.databind.node.ArrayNode;
import org.junit.jupiter.api.Test;
import org.junit.jupiter.params.ParameterizedTest;
import org.junit.jupiter.params.provider.MethodSource;

import static org.keycloak.OID4VCConstants.CLAIM_NAME_CNF;
import static org.keycloak.OID4VCConstants.CLAIM_NAME_ISSUER;
import static org.keycloak.OID4VCConstants.CLAIM_NAME_JWK;
import static org.keycloak.OID4VCConstants.CLAIM_NAME_SD;
import static org.keycloak.OID4VCConstants.CLAIM_NAME_SD_HASH_ALGORITHM;
import static org.keycloak.OID4VCConstants.CLAIM_NAME_VCT;

import static org.junit.jupiter.api.Assertions.assertEquals;
import static org.junit.jupiter.api.Assertions.assertNotNull;
import static org.junit.jupiter.api.Assertions.assertTrue;

/**
Expand Down Expand Up @@ -93,12 +104,52 @@ public void buildSdJwtCredential_WithNoClaims() throws Exception {
);
}

static Stream<Integer> decoyCountProvider() {
return Stream.of(0, 1, 5);
}

@ParameterizedTest
@MethodSource("decoyCountProvider")
public void shouldBindHolderKeyWithCnfClaim(int decoys) throws Exception {
CredentialBuildConfig credentialBuildConfig = new CredentialBuildConfig()
.setCredentialIssuer(TEST_ISSUER_DID)
.setCredentialType("https://credentials.example.com/test-credential")
.setTokenJwsType(VCFormat.SD_JWT_VC)
.setHashAlgorithm(OID4VCConstants.SD_HASH_DEFAULT_ALGORITHM)
.setNumberOfDecoys(decoys)
.setSdJwtVisibleClaims(List.of(CLAIM_NAME_CNF));

VerifiableCredential testCredential = getTestCredential(
Map.of("id", String.format("uri:uuid:%s", UUID.randomUUID()), "test", "value"));

SdJwtCredentialBody sdJwtCredentialBody = new SdJwtCredentialBuilder()
.buildCredentialBody(testCredential, credentialBuildConfig);

var holderKeyPair = KeyPairGenerator.getInstance("EC").generateKeyPair();
JWK holderJwk = JWKBuilder.create().kid("holder-key-1").ec(holderKeyPair.getPublic());
sdJwtCredentialBody.addKeyBinding(holderJwk);

String sdJwtString = sdJwtCredentialBody.sign(exampleSigner());
SdJwtVP sdJwt = SdJwtVP.of(sdJwtString);
IssuerSignedJWT jwt = sdJwt.getIssuerSignedJWT();

JsonNode cnfNode = jwt.getPayload().get(CLAIM_NAME_CNF);
assertNotNull(cnfNode, "The cnf claim must be present in the SD-JWT payload (decoys=" + decoys + ")");

JsonNode jwkNode = cnfNode.get(CLAIM_NAME_JWK);
assertNotNull(jwkNode, "The cnf claim must contain a jwk field");
assertEquals("holder-key-1", jwkNode.get("kid").asText(),
"The bound JWK must have the holder's key ID");
assertEquals("EC", jwkNode.get("kty").asText(),
"The bound JWK must have the correct key type");
}

public void testSignSDJwtCredential(Map<String, Object> claims, int decoys, List<String> visibleClaims)
throws VerificationException {
CredentialBuildConfig credentialBuildConfig = new CredentialBuildConfig()
.setCredentialIssuer(TEST_ISSUER_DID)
.setCredentialType("https://credentials.example.com/test-credential")
.setTokenJwsType("example+sd-jwt")
.setTokenJwsType(VCFormat.SD_JWT_VC)
.setHashAlgorithm(OID4VCConstants.SD_HASH_DEFAULT_ALGORITHM)
.setNumberOfDecoys(decoys)
.setSdJwtVisibleClaims(visibleClaims);
Expand Down
3 changes: 2 additions & 1 deletion ...base/src/test/java/org/keycloak/tests/oid4vc/issuance/signing/LDCredentialSignerTest.java
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Expand Up @@ -23,6 +23,7 @@
import org.keycloak.protocol.oid4vc.model.CredentialSubject;
import org.keycloak.protocol.oid4vc.model.VerifiableCredential;
import org.keycloak.protocol.oid4vc.model.vcdm.LdProof;
import org.keycloak.representations.JsonWebToken;
import org.keycloak.representations.idm.ComponentRepresentation;
import org.keycloak.testframework.annotations.KeycloakIntegrationTest;
import org.keycloak.testframework.annotations.TestSetup;
Expand Down Expand Up @@ -65,7 +66,7 @@ public void testUnsupportedCredentialBody() throws Throwable {
CredentialSignerException.class,
() -> new LDCredentialSigner(session, new StaticTimeProvider(1000))
.signCredential(
new JwtCredentialBody(new JWSBuilder().jsonContent(Map.of())),
new JwtCredentialBody(new JWSBuilder(), new JsonWebToken()),
new CredentialBuildConfig()
)
)
Expand Down
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