diff --git a/Lib/http/cookies.py b/Lib/http/cookies.py
--- a/Lib/http/cookies.py
+++ b/Lib/http/cookies.py
@@ -338,6 +338,8 @@
         "version"  : "Version",
     }
 
+    _flags = {'secure', 'httponly'}
+
     def __init__(self):
         # Set defaults
         self.key = self.value = self.coded_value = None
@@ -435,15 +437,18 @@
     (?P<key>                       # Start of group 'key'
     """ + _LegalCharsPatt + r"""+?   # Any word of at least one letter
     )                              # End of group 'key'
-    \s*=\s*                        # Equal Sign
-    (?P<val>                       # Start of group 'val'
-    "(?:[^\\"]|\\.)*"                # Any doublequoted string
-    |                                # or
+    (                              # Optional group: there may not be a value.
+    \s*=\s*                          # Equal Sign
+    (?P<val>                         # Start of group 'val'
+    "(?:[^\\"]|\\.)*"                  # Any doublequoted string
+    |                                  # or
     \w{3},\s[\w\d\s-]{9,11}\s[\d:]{8}\sGMT  # Special case for "expires" attr
-    |                                # or
-    """ + _LegalCharsPatt + r"""*    # Any word or empty string
-    )                              # End of group 'val'
-    \s*;?                          # Probably ending in a semi-colon
+    |                                  # or
+    """ + _LegalCharsPatt + r"""*      # Any word or empty string
+    )                                # End of group 'val'
+    )?                             # End of optional value group
+    \s*                            # Any number of spaces.
+    (\s+|;|$)                      # Ending either at space, semicolon, or EOS.
     """, re.ASCII)                 # May be removed if safe.
 
 
@@ -549,8 +554,12 @@
                     M[key[1:]] = value
             elif key.lower() in Morsel._reserved:
                 if M:
-                    M[key] = _unquote(value)
-            else:
+                    if value is None:
+                        if key.lower() in Morsel._flags:
+                            M[key] = True
+                    else:
+                        M[key] = _unquote(value)
+            elif value is not None:
                 rval, cval = self.value_decode(value)
                 self.__set(key, rval, cval)
                 M = self[key]
diff --git a/Lib/test/test_http_cookies.py b/Lib/test/test_http_cookies.py
--- a/Lib/test/test_http_cookies.py
+++ b/Lib/test/test_http_cookies.py
@@ -109,13 +109,51 @@
         self.assertEqual(C.output(),
                          'Set-Cookie: Customer="WILE_E_COYOTE"; Max-Age=10')
 
-        # others
+    def test_set_secure_httponly_attrs(self):
         C = cookies.SimpleCookie('Customer="WILE_E_COYOTE"')
         C['Customer']['secure'] = True
         C['Customer']['httponly'] = True
         self.assertEqual(C.output(),
             'Set-Cookie: Customer="WILE_E_COYOTE"; httponly; secure')
 
+    def test_secure_httponly_false_if_not_present(self):
+        C = cookies.SimpleCookie()
+        C.load('eggs=scrambled; Path=/bacon')
+        self.assertFalse(C['eggs']['httponly'])
+        self.assertFalse(C['eggs']['secure'])
+
+    def test_secure_httponly_true_if_present(self):
+        # Issue 16611
+        C = cookies.SimpleCookie()
+        C.load('eggs=scrambled; httponly; secure; Path=/bacon')
+        self.assertTrue(C['eggs']['httponly'])
+        self.assertTrue(C['eggs']['secure'])
+
+    def test_secure_httponly_true_if_have_value(self):
+        # This isn't really valid, but demonstrates what the current code
+        # is expected to do in this case.
+        C = cookies.SimpleCookie()
+        C.load('eggs=scrambled; httponly=foo; secure=bar; Path=/bacon')
+        self.assertTrue(C['eggs']['httponly'])
+        self.assertTrue(C['eggs']['secure'])
+        # Here is what it actually does; don't depend on this behavior.  These
+        # checks are testing backward compatibility for issue 16611.
+        self.assertEqual(C['eggs']['httponly'], 'foo')
+        self.assertEqual(C['eggs']['secure'], 'bar')
+
+    def test_bad_attrs(self):
+        # issue 16611: make sure we don't break backward compatibility.
+        C = cookies.SimpleCookie()
+        C.load('cookie=with; invalid; version; second=cookie;')
+        self.assertEqual(C.output(),
+            'Set-Cookie: cookie=with\r\nSet-Cookie: second=cookie')
+
+    def test_extra_spaces(self):
+        C = cookies.SimpleCookie()
+        C.load('eggs  =  scrambled  ;  secure  ;  path  =  bar   ; foo=foo   ')
+        self.assertEqual(C.output(),
+            'Set-Cookie: eggs=scrambled; Path=bar; secure\r\nSet-Cookie: foo=foo')
+
     def test_quoted_meta(self):
         # Try cookie with quoted meta-data
         C = cookies.SimpleCookie()