diff --git a/lib/spack/spack/util/crypto.py b/lib/spack/spack/util/crypto.py
index 566e99da216e00fb5eae9a9cd41da55589901504..74a6ee06bd7d9da901a8c61286718472ba4f3cf9 100644
--- a/lib/spack/spack/util/crypto.py
+++ b/lib/spack/spack/util/crypto.py
@@ -133,7 +133,7 @@ def __init__(self, hexdigest, **kwargs):
     @property
     def hash_name(self):
         """Get the name of the hash function this Checker is using."""
-        return self.hash_fun().name
+        return self.hash_fun().name.lower()
 
     def check(self, filename):
         """Read the file with the specified name and check its checksum