pydns driver did not join split TXT records. Try for Milter.dns which

follows CNAME (is this needed?)

dkim/__init__.py

@@ -348,7 +348,7 @@ class DKIM(object):
     try:
         pk = parse_public_key(base64.b64decode(pub[b'p']))
     except (TypeError,UnparsableKeyError) as e:
-        raise KeyFormatError("could not parse public key: %s" % e)
+        raise KeyFormatError("could not parse public key (%s): %s" % (pub[b'p'],e))
 
     include_headers = re.split(br"\s*:\s*", sig[b'h'])
     h = hasher()

dkim/dns.py

@@ -42,19 +42,31 @@ def get_txt_pydns(name):
     response = DNS.DnsRequest(name, qtype='txt').req()
     if not response.answers:
         return None
-    return response.answers[0]['data'][0]
+    return b''.join(response.answers[0]['data'])
 
+def get_txt_Milter_dns(name):
+    """Return a TXT record associated with a DNS name."""
+    # Older pydns releases don't like a trailing dot.
+    if name.endswith('.'):
+        name = name[:-1]
+    sess = Session()
+    a = sess.dns(name,'TXT')
+    if a: return b''.join(a[0])
+    return None
 
 # Prefer dnspython if it's there, otherwise use pydns.
 try:
     import dns.resolver
     _get_txt = get_txt_dnspython
+except ImportError:
+    try:
+        from Milter.dns import Session
+        _get_txt = get_txt_Milter_dns
     except ImportError:
         import DNS
         DNS.DiscoverNameServers()
         _get_txt = get_txt_pydns
 
-
 def get_txt(name):
     """Return a TXT record associated with a DNS name.