diff --git a/utilities/on_subscibe-service/java/src/main/java/ondc/onboarding/utility/Routes.java b/utilities/on_subscibe-service/java/src/main/java/ondc/onboarding/utility/Routes.java
index 9d8c9d5..67d94e8 100644
--- a/utilities/on_subscibe-service/java/src/main/java/ondc/onboarding/utility/Routes.java
+++ b/utilities/on_subscibe-service/java/src/main/java/ondc/onboarding/utility/Routes.java
@@ -8,9 +8,12 @@
 import java.net.http.HttpResponse;
 import java.security.*;
 import java.security.spec.InvalidKeySpecException;
-import java.util.Arrays;
+import java.text.DateFormat;
+import java.text.SimpleDateFormat;
 import java.util.Base64;
+import java.util.Date;
 import java.util.Map;
+import java.util.TimeZone;
 
 import com.fasterxml.jackson.databind.JsonNode;
 import org.json.JSONException;
@@ -42,13 +45,26 @@ public class Routes extends  Utils{
 
     @Autowired
     private String gatewayUrl;
-    private Logger logger =  LoggerFactory.getLogger(Routes.class);;
+    private final Logger logger =  LoggerFactory.getLogger(Routes.class);;
 
     @GetMapping("/get-keys")
     public ResponseEntity<Map<String,byte[]>> getKeys (){
         return ResponseEntity.ok().contentType(MediaType.APPLICATION_JSON).body(keys);
     }
 
+    @PostMapping("/create-header")
+    public
+    String createHeader(@RequestBody JsonNode req) throws Exception {
+        long created = System.currentTimeMillis() / 1000L;
+        long expires = created + 300000;
+        String hashedReq = hashMassage(req.get("value").toString(),created,expires);
+        String signature = sign(Base64.getDecoder().decode(req.get("private_key").asText()),hashedReq.getBytes());
+        String subscriberId = "altiux.com";
+        String uniqueKeyId = "c9aa1b41-04e9-43e2-bd89-9ddcdecbf4cf";
+
+        return "Signature keyId=\"" + subscriberId + "|" + uniqueKeyId + "|" + "ed25519\"" + ",algorithm=\"ed25519\"," + "created=\"" + created + "\",expires=\"" + expires + "\",headers=\"(created) (expires)" + " digest\",signature=\"" + signature + "\"";
+    }
+
     @PostMapping("/subscribe")
     public ResponseEntity<String> subscribe(@RequestBody JsonNode subscribeBody) throws NoSuchPaddingException, IllegalBlockSizeException, BadPaddingException, NoSuchAlgorithmException, InvalidKeyException, NoSuchProviderException, JSONException, IOException, InterruptedException {
 
diff --git a/utilities/on_subscibe-service/java/src/main/java/ondc/onboarding/utility/Utils.java b/utilities/on_subscibe-service/java/src/main/java/ondc/onboarding/utility/Utils.java
index 063a9e7..ac3083d 100644
--- a/utilities/on_subscibe-service/java/src/main/java/ondc/onboarding/utility/Utils.java
+++ b/utilities/on_subscibe-service/java/src/main/java/ondc/onboarding/utility/Utils.java
@@ -5,6 +5,7 @@
 
 import javax.crypto.*;
 import javax.crypto.spec.SecretKeySpec;
+import java.nio.charset.StandardCharsets;
 import java.security.*;
 import java.security.spec.InvalidKeySpecException;
 import java.security.spec.PKCS8EncodedKeySpec;
@@ -33,17 +34,34 @@ public static CryptoKeyPair generateEncDecKey() throws InvalidKeyException, NoSu
         return new CryptoKeyPair(kp.getPublic().getEncoded(),kp.getPrivate().getEncoded());
     }
 
-    public static String fromBase64(byte[] src){
+    public static String toBase64(byte[] src){
         return Base64.getEncoder().encodeToString(src);
     }
 
+    public static  String hashMassage(String req, long created,long expires) throws Exception {
+        byte[] digest = generateBlakeHash(req);
+        return """
+            (created): %s
+            (expires): %s
+            digest: BLAKE-512=%s""".formatted(created,expires, toBase64(digest));
+    }
+    public static byte[] generateBlakeHash(String req) throws Exception {
+        if (Security.getProvider(BouncyCastleProvider.PROVIDER_NAME) == null) {
+            Security.addProvider(new BouncyCastleProvider());
+        }
+        MessageDigest digest = MessageDigest.getInstance("BLAKE2B-512", BouncyCastleProvider.PROVIDER_NAME);
+        digest.reset();
+        digest.update(req.getBytes(StandardCharsets.UTF_8));
+        return digest.digest();
+    }
+
     public static String sign(byte[] privateKey,byte[] message) {
         // initialise signature variable
         byte[] signature = new byte[Ed25519.SIGNATURE_SIZE];
 
         // sign the received message with given private key
         Ed25519.sign(privateKey, 0, message, 0, message.length, signature, 0);
-        return  fromBase64(signature);
+        return  toBase64(signature);
     }
 
     public static byte[] encryptDecrypt(int mode, byte[] challenge_string,byte[] privateKey, byte[] publicKey) throws NoSuchAlgorithmException, NoSuchProviderException, InvalidKeySpecException, InvalidKeyException, NoSuchPaddingException, IllegalBlockSizeException, BadPaddingException, InvalidKeySpecException {