diff --git a/mes/客户端代码（C#）.md b/mes/客户端代码（C#）.md
index e60d0e1..143cfdd 100644
--- a/mes/客户端代码（C#）.md
+++ b/mes/客户端代码（C#）.md
@@ -89,7 +89,7 @@ public sealed class Client3
             var chars = new char[hash.Length * 2];
             for (var i = 0; i < hash.Length; i++)
             {
-                var b = bytes[i];
+                var b = hash[i];
                 var offset = i * 2;
                 chars[offset] = hex[b / 16];
                 chars[offset + 1] = hex[b % 16];