diff --git a/Lib/urllib2.py b/Lib/urllib2.py
index 1458826..76035a3 100644
--- a/Lib/urllib2.py
+++ b/Lib/urllib2.py
@@ -682,7 +682,7 @@
             proxy_type = orig_type
         if user and password:
             user_pass = '%s:%s' % (unquote(user), unquote(password))
-            creds = str(base64.b64encode(user_pass)).strip()
+            creds = base64.b64encode(user_pass.encode()).decode("ascii")
             req.add_header('Proxy-authorization', 'Basic ' + creds)
         hostport = unquote(hostport)
         req.set_proxy(hostport, proxy_type)
@@ -808,7 +808,7 @@
         user, pw = self.passwd.find_user_password(realm, host)
         if pw is not None:
             raw = "%s:%s" % (user, pw)
-            auth = 'Basic %s' % base64.b64encode(raw).strip().decode()
+            auth = "Basic " + base64.b64encode(raw.encode()).decode("ascii")
             if req.headers.get(self.auth_header, None) == auth:
                 return None
             req.add_header(self.auth_header, auth)