diff --git a/sleekxmpp/plugins/xep_0047/stanza.py b/sleekxmpp/plugins/xep_0047/stanza.py
index e3b5551..2e4f8cc 100644
--- a/sleekxmpp/plugins/xep_0047/stanza.py
+++ b/sleekxmpp/plugins/xep_0047/stanza.py
@@ -46,14 +46,17 @@ class Data(ElementBase):
         self._set_attr('seq', str(value))
 
     def get_data(self):
-        b64_data = self._get_sub_text('data', '')
+        b64_data = self.xml.text
         if VALID_B64.match(b64_data).group() == b64_data:
             return from_b64(b64_data)
         else:
             raise XMPPError('not-acceptable')
 
     def set_data(self, value):
-        self._set_sub_text('data', to_b64(value))
+        self.xml.text = to_64(value)
+
+    def del_data(self):
+        self.xml.text = ''
 
 
 class Close(ElementBase):
diff --git a/tests/test_stanza_xep_0047.py b/tests/test_stanza_xep_0047.py
new file mode 100644
index 0000000..1b21252
--- /dev/null
+++ b/tests/test_stanza_xep_0047.py
@@ -0,0 +1,77 @@
+from sleekxmpp.test import *
+from sleekxmpp.plugins.xep_0047 import Data
+
+
+class TestIBB(SleekTest):
+
+    def setUp(self):
+        register_stanza_plugin(Iq, Data)
+
+    def testInvalidBase64MidEqual(self):
+        """
+        Test detecting invalid base64 data with = inside the
+        character data instead of at the end.
+        """
+        iq = Iq(xml=ET.fromstring("""
+          <iq type="set" id="0" to="tester@localhost">
+            <data xmlns="http://jabber.org/protocol/ibb" seq="0">
+              ABC=DEFGH
+            </data>
+          </iq>
+        """))
+
+        errored = False
+
+        try:
+            data = iq['ibb_data']['data']
+        except XMPPError:
+            errored = True
+
+        self.assertTrue(errored, "ABC=DEFGH did not raise base64 error")
+
+    def testInvalidBase64PrefixEqual(self):
+        """
+        Test detecting invalid base64 data with = as a prefix
+        to the character data.
+        """
+        iq = Iq(xml=ET.fromstring("""
+          <iq type="set" id="0" to="tester@localhost">
+            <data xmlns="http://jabber.org/protocol/ibb" seq="0">
+              =ABCDEFGH
+            </data>
+          </iq>
+        """))
+
+        errored = False
+
+        try:
+            data = iq['ibb_data']['data']
+        except XMPPError:
+            errored = True
+
+        self.assertTrue(errored, "=ABCDEFGH did not raise base64 error")
+
+    def testInvalidBase64Alphabet(self):
+        """
+        Test detecting invalid base64 data with characters
+        outside of the base64 alphabet.
+        """
+        iq = Iq(xml=ET.fromstring("""
+          <iq type="set" id="0" to="tester@localhost">
+            <data xmlns="http://jabber.org/protocol/ibb" seq="0">
+              ABCD?EFGH
+            </data>
+          </iq>
+        """))
+
+        errored = False
+
+        try:
+            data = iq['ibb_data']['data']
+        except XMPPError:
+            errored = True
+
+        self.assertTrue(errored, "ABCD?EFGH did not raise base64 error")
+
+
+suite = unittest.TestLoader().loadTestsFromTestCase(TestIBB)