diff --git a/README.md b/README.md
index 4a8c19e..7b2e4f5 100644
--- a/README.md
+++ b/README.md
@@ -448,7 +448,7 @@ onCommandPacket = { _, jsonObject ->
 
 更多 `Command` 数据包的数据结构详见本项目的 [/record/直播弹幕](record/直播弹幕) 文件夹.
 
-注意, `start()` 方法会 suspend 当前协程直到连接关闭, 如果当前协程上下文还需要执行更多逻辑则如下所示
+注意, `start()` 方法会 suspend 当前协程直到连接关闭, 如果当前协程还需要执行更多逻辑则如下所示
 
 ```kotlin
 val liveClient = bilibiliClient.liveClient(args)
@@ -468,5 +468,9 @@ onClose = { liveClient, closeReason ->
 }
 ```
 
+如果网络不可达, 那么 `start()` 方法会抛出异常, 且不会触发 `onConnect` 以及 `onClose` 回调.
+
+如果数据包被中间人修改, 那么可能不会触发 `onConnect` 回调, 但是会触发 `onClose`.
+
 # License
 GPL V3
diff --git a/src/main/kotlin/com/hiczp/bilibili/api/CipherExtension.kt b/src/main/kotlin/com/hiczp/bilibili/api/CipherExtension.kt
index 7407dfc..c81bb55 100644
--- a/src/main/kotlin/com/hiczp/bilibili/api/CipherExtension.kt
+++ b/src/main/kotlin/com/hiczp/bilibili/api/CipherExtension.kt
@@ -11,7 +11,7 @@ fun String.md5() =
             md5Instance.digest(toByteArray()).forEach {
                 val value = it.toInt() and 0xFF
                 val high = value / 16
-                val low = value - high * 16
+                val low = value % 16
                 append(if (high <= 9) '0' + high else 'a' - 10 + high)
                 append(if (low <= 9) '0' + low else 'a' - 10 + low)
             }
@@ -20,4 +20,4 @@ fun String.md5() =
 /**
  * 签名算法为 "$排序后的参数字符串$appSecret".md5()
  */
-fun calculateSign(sortedQuery: String, appSecret: String) = (sortedQuery + appSecret).md5()
+internal fun calculateSign(sortedQuery: String, appSecret: String) = (sortedQuery + appSecret).md5()
diff --git a/src/main/kotlin/com/hiczp/bilibili/api/live/websocket/Packet.kt b/src/main/kotlin/com/hiczp/bilibili/api/live/websocket/Packet.kt
index e31cdf1..846e922 100644
--- a/src/main/kotlin/com/hiczp/bilibili/api/live/websocket/Packet.kt
+++ b/src/main/kotlin/com/hiczp/bilibili/api/live/websocket/Packet.kt
@@ -10,18 +10,18 @@ import java.nio.ByteBuffer
  * 数据包模型
  * 由于 Android APP 并未全线换成 wss, 以下用的是移动版网页的协议
  * 数据包头部结构  00 00 00 65  00 10 00 01  00 00 00 07  00 00 00 01
- *              |数据包总长度| |头长| |ver|  |数据包类型 |  | single |
+ *              |数据包总长度| |头长| |tag|  |数据包类型 |  |  tag  |
  *
- * @param protocolVersion 协议版本
+ * @param tagShort 一种 tag, 如果是非 command 数据包则为 1, 否则为 0, short 类型
  * @param packetType 数据包类型
- * @param single 如果一个 Message 只有一个数据包则为 1, 否则为 0
+ * @param tag 同 tagShort, 但是为 int 类型
  * @param content 正文内容
  */
 @Suppress("MemberVisibilityCanBePrivate")
 class Packet(
-        val protocolVersion: Short = 1,
+        val tagShort: Short = 1,
         val packetType: PacketType,
-        val single: Int = 1,
+        val tag: Int = 1,
         val content: ByteBuffer
 ) {
     val totalLength
@@ -33,9 +33,9 @@ class Packet(
             ByteBuffer.allocate(totalLength)
                     .putInt(totalLength)
                     .putShort(headerLength)
-                    .putShort(protocolVersion)
+                    .putShort(tagShort)
                     .putInt(packetType.value)
-                    .putInt(single)
+                    .putInt(tag)
                     .put(content).apply {
                         flip()
                     }!!
@@ -59,14 +59,14 @@ internal fun Frame.toPackets(): List<Packet> {
         val startPosition = buffer.position()
         val totalLength = buffer.int
         buffer.position(buffer.position() + 2)    //skip headerLength
-        val protocolVersion = buffer.short
+        val tagShort = buffer.short
         val packetType = PacketType.getByValue(buffer.int)
-        val sequence = buffer.int
+        val tag = buffer.int
         buffer.limit(startPosition + totalLength)
         val content = buffer.slice()
         buffer.position(buffer.limit())
         buffer.limit(bufferLength)
-        list.add(Packet(protocolVersion, packetType, sequence, content))
+        list.add(Packet(tagShort, packetType, tag, content))
     }
     return list
 }