diff --git a/db_transfer.py b/db_transfer.py
index e96819a..ba6e3ea 100644
--- a/db_transfer.py
+++ b/db_transfer.py
@@ -8,6 +8,7 @@ import sys
 from server_pool import ServerPool
 import Config
 import traceback
+from shadowsocks import common
 
 class DbTransfer(object):
 
@@ -115,7 +116,7 @@ class DbTransfer(object):
 				allow = False
 
 			port = row['port']
-			passwd = row['passwd']
+			passwd = common.to_bytes(row['passwd'])
 
 			if port not in cur_servers:
 				cur_servers[port] = passwd
diff --git a/server_pool.py b/server_pool.py
index 77d300d..4b4663c 100644
--- a/server_pool.py
+++ b/server_pool.py
@@ -187,9 +187,9 @@ class ServerPool(object):
 
 		if 'server_ipv6' in self.config:
 			if port not in self.tcp_ipv6_servers_pool:
-				logging.info("stopped server at %s:%d already stop" % (self.config['server_ipv6'], port))
+				logging.info("stopped server at [%s]:%d already stop" % (self.config['server_ipv6'], port))
 			else:
-				logging.info("stopped server at %s:%d" % (self.config['server_ipv6'], port))
+				logging.info("stopped server at [%s]:%d" % (self.config['server_ipv6'], port))
 				try:
 					self.tcp_ipv6_servers_pool[port].close(False)
 					del self.tcp_ipv6_servers_pool[port]
diff --git a/shadowsocks/encrypt.py b/shadowsocks/encrypt.py
index 834b18c..b7981b4 100644
--- a/shadowsocks/encrypt.py
+++ b/shadowsocks/encrypt.py
@@ -77,6 +77,7 @@ class Encryptor(object):
         self.iv = None
         self.iv_sent = False
         self.cipher_iv = b''
+        self.iv_buf = b''
         self.decipher = None
         method = method.lower()
         self._method_info = self.get_method_info(method)
@@ -122,16 +123,20 @@ class Encryptor(object):
     def decrypt(self, buf):
         if len(buf) == 0:
             return buf
-        if self.decipher is None:
-            decipher_iv_len = self._method_info[1]
-            decipher_iv = buf[:decipher_iv_len]
+        if self.decipher is not None: #optimize
+            return self.decipher.update(buf)
+
+        decipher_iv_len = self._method_info[1]
+        if len(self.iv_buf) <= decipher_iv_len:
+            self.iv_buf += buf
+        if len(self.iv_buf) > decipher_iv_len:
+            decipher_iv = self.iv_buf[:decipher_iv_len]
             self.decipher = self.get_cipher(self.key, self.method, 0,
                                             iv=decipher_iv)
-            buf = buf[decipher_iv_len:]
-            if len(buf) == 0:
-                return buf
-        return self.decipher.update(buf)
-
+            buf = self.iv_buf[decipher_iv_len:]
+            return self.decipher.update(buf)
+        else:
+            return b''
 
 def encrypt_all(password, method, op, data):
     result = []