diff --git a/acme/acme/challenges.py b/acme/acme/challenges.py
index 976d7ab12..336e6c4e5 100644
--- a/acme/acme/challenges.py
+++ b/acme/acme/challenges.py
@@ -228,6 +228,9 @@ class HTTP01Response(KeyAuthorizationChallengeResponse):
 
     """
 
+    WHITESPACE_CUTSET = "\n\r\t "
+    """Whitespace characters which should be ignored at the end of the body."""
+
     def simple_verify(self, chall, domain, account_public_key, port=None):
         """Simple verify.
 
@@ -273,10 +276,11 @@ class HTTP01Response(KeyAuthorizationChallengeResponse):
                          found_ct, chall.CONTENT_TYPE)
             return False
 
-        if self.key_authorization != http_response.text:
+        challenge_response = http_response.text.rstrip(self.WHITESPACE_CUTSET)
+        if self.key_authorization != challenge_response:
             logger.debug("Key authorization from response (%r) doesn't match "
                          "HTTP response (%r)", self.key_authorization,
-                         http_response.text)
+                         challenge_response)
             return False
 
         return True
diff --git a/acme/acme/challenges_test.py b/acme/acme/challenges_test.py
index c4f3d6c61..7cf387ece 100644
--- a/acme/acme/challenges_test.py
+++ b/acme/acme/challenges_test.py
@@ -126,6 +126,16 @@ class HTTP01ResponseTest(unittest.TestCase):
         self.assertFalse(self.response.simple_verify(
             self.chall, "local", KEY.public_key()))
 
+    @mock.patch("acme.challenges.requests.get")
+    def test_simple_verify_whitespace_validation(self, mock_get):
+        from acme.challenges import HTTP01Response
+        mock_get.return_value = mock.MagicMock(
+            text=(self.chall.validation(KEY) +
+                  HTTP01Response.WHITESPACE_CUTSET), headers=self.good_headers)
+        self.assertTrue(self.response.simple_verify(
+            self.chall, "local", KEY.public_key()))
+        mock_get.assert_called_once_with(self.chall.uri("local"))
+
     @mock.patch("acme.challenges.requests.get")
     def test_simple_verify_bad_content_type(self, mock_get):
         mock_get().text = self.chall.token