diff --git a/lib/ProofSet.js b/lib/ProofSet.js
index 3641c79e..3f2b5d8f 100644
--- a/lib/ProofSet.js
+++ b/lib/ProofSet.js
@@ -227,7 +227,7 @@ function _getProofs({document}) {
   proofSet = proofSet.map(proof => {
     const {cryptosuite} = proof;
     // JCS Data Integrity Suites require unmodified proofs
-    if(cryptosuite && cryptosuite.includes('-jcs-')) {
+    if(cryptosuite?.includes?.('-jcs-')) {
       return proof;
     }
     return {'@context': context, ...proof};