--- a/shasum.py	Sat Feb 26 17:31:40 2022 +0100
+++ b/shasum.py	Sat Feb 26 17:48:20 2022 +0100
@@ -27,6 +27,10 @@
 import binascii
 import errno
 import hashlib
+try:
+    from hmac import compare_digest
+except ImportError:
+    compare_digest = None
 import io
 try:
     import mmap
@@ -208,7 +212,10 @@
                 return False
         else:
             return False
-    return given_digest == exd
+    if compare_digest:
+        return compare_digest(given_digest, exd)
+    else:
+        return given_digest == exd
 
 
 def verify_digests_with_checklist(opts):