Check announced posts for invalid ciphertext

posts.py

@@ -32,6 +32,7 @@ from webfinger import webfingerHandle
 from httpsig import createSignedHeader
 from siteactive import siteIsActive
 from languages import understoodPostLanguage
+from utils import invalidCiphertext
 from utils import hasObjectStringType
 from utils import removeIdEnding
 from utils import replaceUsersWithAt
@@ -4602,6 +4603,11 @@ def downloadAnnounce(session, baseDir: str, httpPrefix: str,
                             recentPostsCache)
             return None
 
+        if invalidCiphertext(contentStr):
+            print('WARN: Invalid ciphertext within announce ' +
+                  str(announcedJson))
+            return None
+
         # remove any long words
         contentStr = removeLongWords(contentStr, 40, [])