diff --git a/verification/challengeresponse.go b/verification/challengeresponse.go
index 0e5545e..9d4e716 100644
--- a/verification/challengeresponse.go
+++ b/verification/challengeresponse.go
@@ -147,11 +147,11 @@ func wrapEvInCMW(evidence []byte, mt string) ([]byte, string, error) {
 	c.SetMediaType(mt)
 	c.SetValue(evidence)
 	c.SetIndicators(cmw.Evidence)
-	cmw, err := c.Serialize(cmw.CBORArray)
+	cm, err := c.Serialize(cmw.CBORArray)
 	if err != nil {
 		return nil, "", fmt.Errorf("cmw serialization failed: %w", err)
 	}
-	return cmw, cmwMediaType, nil
+	return cm, cmwMediaType, nil
 }
 
 // NewSession runs the first part of the interaction which deals with session