diff --git a/ChangeLog b/ChangeLog
index 5cbe1f5d1..36e17775e 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -7,6 +7,9 @@ Changes in version 0.2.0.33 - 200?-??-??
     - Compile without warnings on solaris.
     - Avoid potential crash on internal error during signature collection.
       Fixes bug 864.  Patch from rovv.
+    - Correct handling of possible malformed authority signing key
+      certificates with internal signature types.  Fixes bug 880.
+      Bugfix on 0.2.0.3-alpha.
 
   o Minor features:
     - Report the case where all signatures in a detached set are rejected
diff --git a/src/or/routerparse.c b/src/or/routerparse.c
index 1520dc32f..7675ef5a8 100644
--- a/src/or/routerparse.c
+++ b/src/or/routerparse.c
@@ -1483,7 +1483,12 @@ authority_cert_parse_from_string(const char *s, const char **end_of_string)
   int found;
 
   s = eat_whitespace(s);
-  eos = strstr(s, "\n-----END SIGNATURE-----\n");
+  eos = strstr(s, "\ndir-key-certification");
+  if (! eos) {
+    log_warn(LD_DIR, "No signature found on key certificate");
+    return NULL;
+  }
+  eos = strstr(eos, "\n-----END SIGNATURE-----\n");
   if (! eos) {
     log_warn(LD_DIR, "No end-of-signature found on key certificate");
     return NULL;