diff --git a/src/allmydata/codec.py b/src/allmydata/codec.py
index ab15e16bd..f75235f6b 100644
--- a/src/allmydata/codec.py
+++ b/src/allmydata/codec.py
@@ -2,8 +2,7 @@
 
 from zope.interface import implements
 from twisted.internet import defer
-import sha
-from allmydata.util import idlib, mathutil
+from allmydata.util import mathutil
 from allmydata.util.assertutil import precondition
 from allmydata.interfaces import ICodecEncoder, ICodecDecoder
 import fec
diff --git a/src/allmydata/test/test_codec.py b/src/allmydata/test/test_codec.py
index c9fe13ef5..ba2f0b34f 100644
--- a/src/allmydata/test/test_codec.py
+++ b/src/allmydata/test/test_codec.py
@@ -1,7 +1,6 @@
 
 import os
 from twisted.trial import unittest
-from twisted.internet import defer
 from twisted.python import log
 from allmydata.codec import ReplicatingEncoder, ReplicatingDecoder, CRSEncoder, CRSDecoder
 import random