diff --git a/build/libraries_sysmenu/sysmenu/ARM9/Makefile b/build/libraries_sysmenu/sysmenu/ARM9/Makefile
index bfa633cb..df505ac3 100644
--- a/build/libraries_sysmenu/sysmenu/ARM9/Makefile
+++ b/build/libraries_sysmenu/sysmenu/ARM9/Makefile
@@ -39,6 +39,7 @@ SRCS			=	sysmenu_lib.c \
 					../common/src/pxi.c \
 					../common/src/mountInfo.c \
 					../common/src/decodeAES.c \
+					../common/src/masterkey.c \
 					$(REVISION_SRC)
 
 
diff --git a/build/libraries_sysmenu/sysmenu/common/src/masterkey.c b/build/libraries_sysmenu/sysmenu/common/src/masterkey.c
new file mode 100644
index 00000000..c30fb93b
--- /dev/null
+++ b/build/libraries_sysmenu/sysmenu/common/src/masterkey.c
@@ -0,0 +1,110 @@
+/*---------------------------------------------------------------------------*
+  Project:  Sample Test
+  File:     test.c
+
+  Copyright 2005 Nintendo.  All rights reserved.
+
+  These coded instructions, statements, and computer programs contain
+  proprietary information of Nintendo of America Inc. and/or Nintendo
+  Company Ltd., and are protected by Federal copyright law.  They may
+  not be disclosed to third parties or copied or duplicated in any form,
+  in whole or in part, without the prior written consent of Nintendo.
+ *---------------------------------------------------------------------------*/
+
+#include <twl.h>
+#include <sysmenu.h>
+
+#define	CODE_LENGTH		8
+
+static u32 Crc32Table[0x100];
+
+// Forward references
+u32 CalcMasterkey(const u8 *src);
+
+static void Crc32Init(void)
+{
+  u32 i, j;
+  u32 poly = 0xedb88320;
+  u32 crc;
+
+  for (i = 0; i < 0x100; i++) {
+    crc = i;
+    for (j = 8; j > 0; j--) {
+      if (crc & 1) {
+        crc = (crc >> 1) ^ poly;
+      } else {
+        crc >>= 1;
+      }
+    }
+    Crc32Table[i] = crc;
+  }
+}
+
+static u32 CalcCrc32(const u8 *src, u32 len)
+{
+  u32 crc = 0xffffffff;
+
+  while (len) {
+    crc = ((crc >> 8) & 0xffffffff) ^ Crc32Table[(crc ^ *src) & 0xff];
+    src++;
+    len--;
+  }
+  return crc;
+}
+
+u32 CalcMasterkey(const u8 *src)
+{
+	static u8 initFlag = 0;
+	u32 key;
+
+	if (initFlag == 0) {
+		Crc32Init();
+		initFlag = 1;
+	}
+
+	key = ((CalcCrc32(src, CODE_LENGTH) ^ 0xaaaa) + 5313) % 100000;
+
+	return key;
+}
+
+//======================================================================
+//
+//  マスターキー算出
+//
+//======================================================================
+u32 SYSM_CalcPCTLMasterKey( void )
+{
+	u32 masterKey;
+	u32 inquiryCode = SYSM_CalcPCTLInquiryCode();
+	u8 arg[ 9 ];
+	RTCDate date;
+	RTC_Init();
+	RTC_GetDate( &date );
+	STD_TSPrintf( (char *)arg, "%02d%02d%04d", date.month, date.day, inquiryCode % 10000 );
+	masterKey = CalcMasterkey( arg );
+	OS_TPrintf( "MasterKey : %05d\n", masterKey );
+	return masterKey;
+}
+
+
+//======================================================================
+//
+//  ペアレンタルコントロール問い合わせ番号算出
+//
+//======================================================================
+u32 SYSM_CalcPCTLInquiryCode( void )
+{
+	int i;
+	u64 num = 0;
+	u8  *p  = (u8 *)&num;
+	u8  macAddr[ 6 ];
+	u32 inquiryCode;
+	OS_GetMacAddress( macAddr );
+	for( i = 5; i >= 0; i-- ) {
+		*p++ = macAddr[ i ];
+	}
+	inquiryCode = (u32)( num % 100000000UL );
+	OS_TPrintf( "InquiryCode : %08d\n", inquiryCode );
+	return inquiryCode;
+}
+
diff --git a/include/sysmenu/sysmenu_lib/common/sysmenu_api.h b/include/sysmenu/sysmenu_lib/common/sysmenu_api.h
index 8886c38d..b7be6e5f 100644
--- a/include/sysmenu/sysmenu_lib/common/sysmenu_api.h
+++ b/include/sysmenu/sysmenu_lib/common/sysmenu_api.h
@@ -129,6 +129,10 @@ extern BOOL SYSM_IsLeapYear100( u32 year );										// 
 // スリープモード
 extern void SYSM_GoSleepMode( void );                                           // スリープモードへの遷移
 
+// ペアレンタルコントロール問い合わせ
+u32 SYSM_CalcPCTLInquiryCode( void );											// 問い合わせコード（１０進８桁）算出
+u32 SYSM_CalcPCTLMasterKey( void );												// マスターキー　　（１０進５桁）算出
+
 #endif
 
 // 状態チェック