added hardening on documents link

components/case/documents.js

@@ -105,12 +105,9 @@ const DocumentDetails = (props) => {
                                         >
                                             <dd className="govuk-summary-list__value govuk-!-font-size-16 ">
                                                 <a
-                                                    href={
-                                                        "/api/proxy/documents/download/" +
-                                                        encryptDocReference(
-                                                            detailsObj.pinswg_isharedocumentreference
-                                                        )
-                                                    }
+                                                    href={encryptDocReference(
+                                                        detailsObj.pinswg_isharedocumentreference
+                                                    )}
                                                 >
                                                     <span className="results-visually-hidden">
                                                         {t(
@@ -194,15 +191,18 @@ const DocumentDetails = (props) => {
         );
     };
 
-    const encryptDocReference = (documentRef) => {
-        var encrypted = encodeURIComponent(
-            CryptoJS.AES.encrypt(
-                documentRef,
-                process.env.NEXT_PUBLIC_ISHARESECRETPHRASE
-            )
-        );
+    const WORDKEY = process.env.NEXT_PUBLIC_HASHKEY;
 
-        return encrypted;
+    const encryptDocReference = (documentRef) => {
+        var hashlink = CryptoJS.HmacSHA256(
+            "/api/proxy/documents/download/" + documentRef,
+            CryptoJS.enc.Hex.parse(WORDKEY)
+        );
+        hashlink = hashlink.toString();
+
+        return (
+            "/api/proxy/documents/download/" + documentRef + "&hash=" + hashlink
+        );
     };
 
     useEffect(() => {