diff --git a/dkim/__init__.py b/dkim/__init__.py
index b4250d7..5df31df 100644
--- a/dkim/__init__.py
+++ b/dkim/__init__.py
@@ -430,8 +430,8 @@ def verify(message, logger=None, dnsfunc=dnstxt):
         return False
 
     # dnstxt wants Unicode
-    selector = sig[b's'].decode('latin-1')
-    domain = sig[b'd'].decode('latin-1')
+    selector = sig[b's'].decode('ascii')
+    domain = sig[b'd'].decode('ascii')
     name = "%s._domainkey.%s." % (selector, domain)
     s = dnsfunc(name).encode('utf-8')
     if not s:
diff --git a/dkim/tests/test_dkim.py b/dkim/tests/test_dkim.py
index a29da30..1a507ee 100644
--- a/dkim/tests/test_dkim.py
+++ b/dkim/tests/test_dkim.py
@@ -53,7 +53,7 @@ class TestSignAndVerify(unittest.TestCase):
 
     def dnsfunc(self, domain):
         self.assertEqual('test._domainkey.example.com.', domain)
-        return read_test_data("test.txt").decode('latin1')
+        return read_test_data("test.txt").decode('utf-8')
 
     def test_verifies(self):
         # A message verifies after being signed.
diff --git a/dkimsign.py b/dkimsign.py
index 5060240..c713e60 100644
--- a/dkimsign.py
+++ b/dkimsign.py
@@ -36,11 +36,11 @@ if sys.version_info[0] >= 3:
     sys.stdin = sys.stdin.detach()
     sys.stdout = sys.stdout.detach()
 
-selector = sys.argv[1].encode('utf-8')
-domain = sys.argv[2].encode('utf-8')
+selector = sys.argv[1].encode('ascii')
+domain = sys.argv[2].encode('ascii')
 privatekeyfile = sys.argv[3]
 if len(sys.argv) > 5:
-    identity = sys.argv[4].encode('utf-8')
+    identity = sys.argv[4].encode('ascii')
 else:
     identity = None