diff --git a/commands/core.py b/commands/core.py
index a7852d53..d56b7bac 100644
--- a/commands/core.py
+++ b/commands/core.py
@@ -2,6 +2,7 @@ import os
 import requests
 
 from command import CommandRegistry
+from little_shit import get_source
 from apiclient import client as api
 
 __registry__ = cr = CommandRegistry()
@@ -20,12 +21,9 @@ def tuling123(args_text, ctx_msg, internal=False):
     url = 'http://www.tuling123.com/openapi/api'
     data = {
         'key': os.environ.get('TURING123_API_KEY'),
-        'info': args_text
+        'info': args_text,
+        'userid': get_source(ctx_msg)
     }
-    if ctx_msg.get('sender_uid'):
-        data['userid'] = ctx_msg.get('sender_uid')
-    elif ctx_msg.get('sender_id'):
-        data['userid'] = ctx_msg.get('sender_id').strip('@')[-32:]
     resp = requests.post(url, data=data)
     if resp.status_code == 200:
         json = resp.json()
diff --git a/filters/speech_recognition_90.py b/filters/speech_recognition_90.py
index cc67e018..828551cb 100644
--- a/filters/speech_recognition_90.py
+++ b/filters/speech_recognition_90.py
@@ -13,6 +13,7 @@ import speech_recognition as sr
 
 from filter import as_filter
 from commands import core
+from little_shit import get_source
 
 
 def _recognize_baidu(wav_path, unique_id, api_key, secret_key, language='zh'):
@@ -74,7 +75,7 @@ def _filter(ctx_msg):
                 service_full_name = '百度语音识别'
                 text = _recognize_baidu(
                     wav_path,
-                    ctx_msg.get('sender_id')[-60:],
+                    get_source(ctx_msg),
                     os.environ.get('BAIDU_SPEECH_API_KEY'),
                     os.environ.get('BAIDU_SPEECH_SECRET_KEY'),
                     language='zh'
diff --git a/little_shit.py b/little_shit.py
index a259387a..ff3c7a69 100644
--- a/little_shit.py
+++ b/little_shit.py
@@ -1,4 +1,5 @@
 import os
+import hashlib
 import random
 from datetime import datetime
 
@@ -47,21 +48,24 @@ def get_source(ctx_msg):
     Source is used to distinguish the interactive sessions.
     Note: This value may change after restarting the bot.
 
-    :return: an unique value representing a source, or a random value if something strange happened
+    :return: a 32 character unique string (md5) representing a source, or a random value if something strange happened
     """
+    source = None
     if ctx_msg.get('via') == 'qq':
         if ctx_msg.get('type') == 'group_message' and ctx_msg.get('group_uid') and ctx_msg.get('sender_uid'):
-            return 'g' + ctx_msg.get('group_uid') + 'p' + ctx_msg.get('sender_uid')
+            source = 'g' + ctx_msg.get('group_uid') + 'p' + ctx_msg.get('sender_uid')
         elif ctx_msg.get('type') == 'discuss_message' and ctx_msg.get('discuss_id') and ctx_msg.get('sender_uid'):
-            return 'd' + ctx_msg.get('discuss_id') + 'p' + ctx_msg.get('sender_uid')
+            source = 'd' + ctx_msg.get('discuss_id') + 'p' + ctx_msg.get('sender_uid')
         elif ctx_msg.get('type') == 'friend_message' and ctx_msg.get('sender_uid'):
-            return 'p' + ctx_msg.get('sender_uid')
+            source = 'p' + ctx_msg.get('sender_uid')
     elif ctx_msg.get('via') == 'wx':
         if ctx_msg.get('type') == 'group_message' and ctx_msg.get('group_id') and ctx_msg.get('sender_id'):
-            return 'g' + ctx_msg.get('group_id') + 'p' + ctx_msg.get('sender_id')
+            source = 'g' + ctx_msg.get('group_id') + 'p' + ctx_msg.get('sender_id')
         elif ctx_msg.get('type') == 'friend_message' and ctx_msg.get('sender_id'):
-            return 'p' + ctx_msg.get('sender_id')
-    return str(int(datetime.now().timestamp())) + str(random.randint(100, 999))
+            source = 'p' + ctx_msg.get('sender_id')
+    if not source:
+        source = str(int(datetime.now().timestamp())) + str(random.randint(100, 999))
+    return hashlib.md5(source.encode('utf-8')).hexdigest()
 
 
 def get_target(ctx_msg):
@@ -69,7 +73,8 @@ def get_target(ctx_msg):
     Target is used to distinguish the records in database.
     Note: This value will not change after restarting the bot.
 
-    :return: an unique value representing a target, or None if there is no persistent unique value
+    :return: an unique string (account id with some flags) representing a target,
+             or None if there is no persistent unique value
     """
     if ctx_msg.get('via') == 'qq':
         if ctx_msg.get('type') == 'group_message' and ctx_msg.get('group_uid'):