diff --git a/securedrop/source_app/info.py b/securedrop/source_app/info.py
index 4c27ba219d..b6025bd08d 100644
--- a/securedrop/source_app/info.py
+++ b/securedrop/source_app/info.py
@@ -1,8 +1,12 @@
 # -*- coding: utf-8 -*-
-
-from io import StringIO
+import six
 from flask import Blueprint, render_template, send_file, current_app
 
+if six.PY2:
+    from cStringIO import StringIO  # noqa
+else:
+    from io import BytesIO  # noqa
+
 
 def make_blueprint(config):
     view = Blueprint('info', __name__)
@@ -19,7 +23,11 @@ def recommend_tor_browser():
     def download_journalist_pubkey():
         journalist_pubkey = current_app.crypto_util.gpg.export_keys(
             config.JOURNALIST_KEY)
-        return send_file(StringIO(journalist_pubkey),
+        if six.PY2:
+            data = StringIO(journalist_pubkey)
+        else:
+            data = BytesIO(journalist_pubkey.encode('utf-8'))
+        return send_file(data,
                          mimetype="application/pgp-keys",
                          attachment_filename=config.JOURNALIST_KEY + ".asc",
                          as_attachment=True)
diff --git a/securedrop/tests/functional/test_source.py b/securedrop/tests/functional/test_source.py
index 55721d71be..a4df1ce0de 100644
--- a/securedrop/tests/functional/test_source.py
+++ b/securedrop/tests/functional/test_source.py
@@ -1,5 +1,6 @@
-from . import source_navigation_steps
+from . import source_navigation_steps, journalist_navigation_steps
 from . import functional_test
+import six
 
 
 class TestSourceInterface(
@@ -17,3 +18,16 @@ def test_lookup_codename_hint(self):
         self._source_chooses_to_login()
         self._source_proceeds_to_login()
         self._source_sees_no_codename()
+
+
+class TestDownloadKey(
+        functional_test.FunctionalTest,
+        journalist_navigation_steps.JournalistNavigationStepsMixin):
+
+    def test_journalist_key_from_source_interface(self):
+        data = self.return_downloaded_content(self.source_location +
+                                              "/journalist-key", None)
+
+        if six.PY3:
+            data = data.decode('utf-8')
+        assert "BEGIN PGP PUBLIC KEY BLOCK" in data