Index: subversion/libsvn_subr/simple_providers.c
===================================================================
--- subversion/libsvn_subr/simple_providers.c   (revision 18843)
+++ subversion/libsvn_subr/simple_providers.c   (working copy)
@@ -86,7 +86,10 @@
                      APR_HASH_KEY_STRING);
   if (str && str->data)
     {
-      *password = str->data;
+      char *decoded_password;
+      decoded_password = apr_palloc(pool, apr_base64_decode_len(str->data));
+      apr_base64_decode(decoded_password, str->data);
+      *password = decoded_password;
       return TRUE;
     }
   return FALSE;
@@ -102,8 +105,11 @@
                     svn_boolean_t non_interactive,
                     apr_pool_t *pool)
 {
+  int len = strlen(password);
+  char *encoded_password = apr_palloc(pool, apr_base64_encode_len(len));
+  apr_base64_encode(encoded_password, password, len);
   apr_hash_set(creds, SVN_AUTH__AUTHFILE_PASSWORD_KEY, APR_HASH_KEY_STRING,
-               svn_string_create(password, pool));
+               svn_string_create(encoded_password, pool));
   return TRUE;
 }