diff --git a/services/src/main/java/org/keycloak/protocol/oid4vc/model/Proof.java b/services/src/main/java/org/keycloak/protocol/oid4vc/model/Proof.java
index 984432e45c..7ec02e334f 100644
--- a/services/src/main/java/org/keycloak/protocol/oid4vc/model/Proof.java
+++ b/services/src/main/java/org/keycloak/protocol/oid4vc/model/Proof.java
@@ -30,15 +30,15 @@ import com.fasterxml.jackson.annotation.JsonProperty;
 public class Proof {
 
     @JsonProperty("proof_type")
-    private ProofType proofType;
+    private String proofType;
 
     private Object proofObject;
 
-    public ProofType getProofType() {
+    public String getProofType() {
         return proofType;
     }
 
-    public Proof setProofType(ProofType proofType) {
+    public Proof setProofType(String proofType) {
         this.proofType = proofType;
         return this;
     }
@@ -51,4 +51,4 @@ public class Proof {
         this.proofObject = proofObject;
         return this;
     }
-}
\ No newline at end of file
+}
diff --git a/services/src/main/java/org/keycloak/protocol/oid4vc/model/ProofType.java b/services/src/main/java/org/keycloak/protocol/oid4vc/model/ProofType.java
index 5306744a15..792f20188d 100644
--- a/services/src/main/java/org/keycloak/protocol/oid4vc/model/ProofType.java
+++ b/services/src/main/java/org/keycloak/protocol/oid4vc/model/ProofType.java
@@ -23,19 +23,10 @@ package org.keycloak.protocol.oid4vc.model;
  *
  * @author <a href="https://github.com/wistefan">Stefan Wiedemann</a>
  */
-public enum ProofType {
+public final class ProofType {
 
-    JWT("jwt"),
-    LD_PROOF("ldp_vp"),
-    CWT("cwt");
+    public static final String JWT = "jwt";
+    public static final String LD_PROOF = "ldp_vp";
+    public static final String CWT = "cwt";
 
-    private final String value;
-
-    ProofType(String value) {
-        this.value = value;
-    }
-
-    public String getValue() {
-        return value;
-    }
-}
\ No newline at end of file
+}