diff --git a/oid4vc-core/src/jwt.rs b/oid4vc-core/src/jwt.rs
index c0c2c640..20cd1e2f 100644
--- a/oid4vc-core/src/jwt.rs
+++ b/oid4vc-core/src/jwt.rs
@@ -50,20 +50,21 @@ where
     Ok(jsonwebtoken::decode::<T>(jwt, &key, &validation)?.claims)
 }
 
-pub fn encode<C, S>(signer: Arc<S>, header: Header, claims: C, subject_syntax_type: &str) -> Result<String>
+pub async fn encode<C, S>(signer: Arc<S>, header: Header, claims: C, subject_syntax_type: &str) -> Result<String>
 where
     C: Serialize,
     S: Sign + ?Sized,
 {
     let kid = signer
         .key_id(subject_syntax_type)
+        .await
         .ok_or(anyhow!("No key identifier found."))?;
 
     let jwt = JsonWebToken::new(header, claims).kid(kid);
 
     let message = [base64_url_encode(&jwt.header)?, base64_url_encode(&jwt.payload)?].join(".");
 
-    let proof_value = signer.sign(&message, subject_syntax_type)?;
+    let proof_value = signer.sign(&message, subject_syntax_type).await?;
     let signature = base64_url::encode(proof_value.as_slice());
     let message = [message, signature].join(".");
     Ok(message)
@@ -97,7 +98,9 @@ mod tests {
             "nonce": "nonce",
         });
         let subject = TestSubject::new("did:test:123".to_string(), "key_id".to_string()).unwrap();
-        let encoded = encode(Arc::new(subject), Header::new(Algorithm::EdDSA), claims, "did:test").unwrap();
+        let encoded = encode(Arc::new(subject), Header::new(Algorithm::EdDSA), claims, "did:test")
+            .await
+            .unwrap();
 
         let verifier = MockVerifier::new();
         let (kid, algorithm) = extract_header(&encoded).unwrap();