diff --git a/src/communication/task_manager/include/task_manager/md5.h b/src/communication/task_manager/include/task_manager/md5.h
index df10a8c..ff247fd 100644
--- a/src/communication/task_manager/include/task_manager/md5.h
+++ b/src/communication/task_manager/include/task_manager/md5.h
@@ -5,7 +5,7 @@
 #include <fstream>
 
 /* Type define */
-typedef unsigned char byte;
+typedef unsigned char MD5_byte;
 typedef unsigned int uint32;
 
 using std::ifstream;
@@ -22,30 +22,30 @@ public:
     void update(const void *input, size_t length);
     void update(const string &str);
     void update(ifstream &in);
-    const byte *digest();
+    const MD5_byte *digest();
     string toString();
     void reset();
 
 private:
-    void update(const byte *input, size_t length);
+    void update(const MD5_byte *input, size_t length);
     void final();
-    void transform(const byte block[64]);
-    void encode(const uint32 *input, byte *output, size_t length);
-    void decode(const byte *input, uint32 *output, size_t length);
-    string bytesToHexString(const byte *input, size_t length);
+    void transform(const MD5_byte block[64]);
+    void encode(const uint32 *input, MD5_byte *output, size_t length);
+    void decode(const MD5_byte *input, uint32 *output, size_t length);
+    string bytesToHexString(const MD5_byte *input, size_t length);
 
     /* class uncopyable */
     MD5(const MD5 &);
     MD5 &operator=(const MD5 &);
 
 private:
-    uint32 _state[4]; /* state (ABCD) */
-    uint32 _count[2]; /* number of bits, modulo 2^64 (low-order word first) */
-    byte _buffer[64]; /* input buffer */
-    byte _digest[16]; /* message digest */
-    bool _finished;   /* calculate finished ? */
+    uint32 _state[4];     /* state (ABCD) */
+    uint32 _count[2];     /* number of bits, modulo 2^64 (low-order word first) */
+    MD5_byte _buffer[64]; /* input buffer */
+    MD5_byte _digest[16]; /* message digest */
+    bool _finished;       /* calculate finished ? */
 
-    static const byte PADDING[64]; /* padding for calculate */
+    static const MD5_byte PADDING[64]; /* padding for calculate */
     static const char HEX[16];
     enum
     {