diff --git a/news/25.feature b/news/25.feature
index 2e9f5e8..f724f96 100644
--- a/news/25.feature
+++ b/news/25.feature
@@ -1 +1 @@
-Work in a FIPS enabled environment [frapell] (#25)
+Work in a FIPS enabled environment by using SHA1 instead of MD5 for computing the cache key [frapell] (#25)
diff --git a/plone/memoize/ram.py b/plone/memoize/ram.py
index d4e76bd..80b71e0 100644
--- a/plone/memoize/ram.py
+++ b/plone/memoize/ram.py
@@ -2,7 +2,7 @@
 """A cache decorator that uses RAMCache by default.
 """
 
-from functools import partial
+from hashlib import sha1
 from plone.memoize import volatile
 from plone.memoize.interfaces import ICacheChooser
 from zope import component
@@ -18,17 +18,6 @@
 except ImportError:
     import cPickle as pickle  # Python 2
 
-try:
-    from hashlib import md5 as md5_original
-except ImportError:
-    from md5 import new as md5_original
-
-try:
-    hashed = md5_original(b'test')
-    md5 = md5_original
-except ValueError:
-    md5 = partial(md5_original, usedforsecurity=False)
-
 
 global_cache = ram.RAMCache()
 global_cache.update(maxAge=86400)
@@ -53,7 +42,7 @@ def __init__(self, client, globalkey=""):
     def _make_key(self, source):
         if issubclass(type(source), six.text_type):
             source = source.encode("utf-8")
-        return md5(source).hexdigest()
+        return sha1(source).hexdigest()
 
     def __getitem__(self, key):
         cached_value = self.client.get(self.globalkey + self._make_key(key))
@@ -75,7 +64,7 @@ def __init__(self, ramcache, globalkey=""):
     def _make_key(self, source):
         if issubclass(type(source), six.text_type):
             source = source.encode("utf-8")
-        return md5(source).digest()
+        return sha1(source).digest()
 
     def __getitem__(self, key):
         value = self.ramcache.query(