diff --git a/src/cryptography/hazmat/primitives/hashes.py b/src/cryptography/hazmat/primitives/hashes.py
index 89e66ab..35b7d64 100644
--- a/src/cryptography/hazmat/primitives/hashes.py
+++ b/src/cryptography/hazmat/primitives/hashes.py
@@ -188,13 +188,9 @@
     block_size = 128
 
     def __init__(self, digest_size):
-        if (
-            digest_size > self._max_digest_size or
-            digest_size < self._min_digest_size
-        ):
-            raise ValueError("Digest size must be {0}-{1}".format(
-                self._min_digest_size, self._max_digest_size)
-            )
+
+        if digest_size != 64:
+            raise ValueError("Digest size must be 64")
 
         self._digest_size = digest_size
 
@@ -209,13 +205,9 @@
     _min_digest_size = 1
 
     def __init__(self, digest_size):
-        if (
-            digest_size > self._max_digest_size or
-            digest_size < self._min_digest_size
-        ):
-            raise ValueError("Digest size must be {0}-{1}".format(
-                self._min_digest_size, self._max_digest_size)
-            )
+
+        if digest_size != 32:
+            raise ValueError("Digest size must be 32")
 
         self._digest_size = digest_size