#include<afx.h>
#include <stdio.h>
#define KEYSIZE 16 /* size of key, in bytes */
#if !defined UINT
typedef unsigned int UINT; /* Should be 32-bit = 4 bytes */
#endif
typedef enum { ShiftLeft, ShiftRight } ShiftDir;
typedef enum { KeyWords = KEYSIZE / 4,
NumRounds = 15, /* Number of cryptographic rounds */
TableSize = 32 /* size of table = 2 * (NumRounds + 1) */
} bogus;
UINT Table[ TableSize ];
UINT L[KeyWords];
UINT ROT(const UINT x, const UINT y, const ShiftDir dir)
{
const unsigned int ShiftAmt = (y & (unsigned int)0x1f);
const unsigned int ShiftBack = 0x20 - ShiftAmt;
unsigned int result;
if (dir == ShiftLeft)
result = (x << ShiftAmt) | (x >> ShiftBack);
else
result = (x >> ShiftAmt) | (x << ShiftBack);
return result;
} /* ROT */
//設置密鑰
void SetKey( unsigned char KeyChar )
{
static unsigned int KeyCntr;
static unsigned int Shift;
int ix = KeyCntr >> 2;
/* this is simply a machine independent way of setting L[i] to
KeyChar[i], without being affect by "endianess". */
L[ ix ] = (L[ ix ] & (~(0xff << Shift))) | (KeyChar << Shift);
Shift = (Shift + 8) & 0x1f;
KeyCntr = (KeyCntr + 1) & (KEYSIZE - 1); /* This Depends on KEYSIZE being */
/* a power of two. The & will */
/* cause the KeyCntr to wrap */
/* and only have values in the */
/* range 0..KEYSIZE-1. */
} /* RC5_Crypto */
//雙字加密函數
/* 2 UINT: input plain text, output encrypted text */
void encrypt(UINT *PlainText, UINT *CryptoText)
{
UINT i, temp;
UINT A;
UINT B;
A = PlainText[0] + Table[0];
B = PlainText[1] + Table[1];
for (i = 1; i <= NumRounds; i++) {
temp = i << 1;
A = ROT(A^B, B, ShiftLeft) + Table[temp];
B = ROT(A^B, A, ShiftLeft) + Table[temp+1];
}
CryptoText[0] = A;
CryptoText[1] = B;
} /* RC5_Cypto::encrypt */
//雙字解密函數
/* 2 UINT input encrypted text, output plain text */
void decrypt(UINT *CryptoText, UINT *PlainText)
{
UINT i, temp;
UINT B;
UINT A;
B = CryptoText[1];
A = CryptoText[0];
for (i=NumRounds; i > 0; i--) {
temp = i << 1;
B = ROT(B - Table[temp+1],A, ShiftRight)^A;
A = ROT(A - Table[temp], B, ShiftRight)^B;
}
PlainText[1] = B-Table[1];
PlainText[0] = A-Table[0];
} /* decrypt */
//初始化函數
void setup() /* secret input key K[0...KEYSIZE-1] */
{
/* magic constants (courtesty of RSA) */
static const UINT ROM[ TableSize ] = { 0xb7e15163, 0x5618cb1c, 0xf45044d5,
0x9287be8e, 0x30bf3847, 0xcef6b200,
0x6d2e2bb9, 0x0b65a572, 0xa99d1f2b,
0x47d498e4, 0xe60c129d, 0x84438c56,
0x227b060f, 0xc0b27fc8, 0x5ee9f981,
0xfd21733a, 0x9b58ecf3, 0x399066ac,
0xd7c7e065, 0x75ff5a1e, 0x1436d3d7,
0xb26e4d90, 0x50a5c749, 0xeedd4102,
0x8d14babb, 0x2b4c3474, 0xc983ae2d,
0x67bb27e6, 0x05f2a19f, 0xa42a1b58,
0x42619511, 0xe0990eca };
UINT i;
UINT A;
UINT B;
UINT j;
UINT k;
/* Copy "ROM" into "RAM" */
for (i=0; i < TableSize; i++)
Table[i] = ROM[i];
/* 3*t > 3*KeyWords */
A = 0;
B = 0;
i = 0;
j = 0;
for (k=0; k < 3*TableSize; k++) {
Table[i] = ROT(Table[i]+(A+B),3, ShiftLeft);
A = Table[i];
L[j] = ROT(L[j]+(A+B),(A+B), ShiftLeft);
B = L[j];
i= (i+1) & (TableSize-1); /* using '&' for % only works for powers of 2 */
j= (j+1) & (KeyWords-1);
}
} /* setup */
//文件加密函數
bool EncryptFile(char *pchFileName)
{
CFile fileb4;
CFile encryptfile;
CFileException e;
char pchEncryptFileName[100];
sprintf(pchEncryptFileName, "$%s", pchFileName);
if( !fileb4.Open( pchFileName, CFile::modeRead | CFile::shareDenyNone, &e ) )
{
printf("%s could not be opened %d/n", pchFileName, e.m_cause);
return false;
}
if ( !encryptfile.Open( pchEncryptFileName, CFile::modeCreate | CFile::modeWrite, &e ))
{
printf("%s could not be created %d/n", pchEncryptFileName, e.m_cause);
fileb4.Close();
return false;
}
BYTE bBuffer[8];
BYTE bEncryptFileHead[8];
UINT uFileLen = fileb4.GetLength();
memcpy(bEncryptFileHead, "ISDN", 4);
memcpy(bEncryptFileHead + 4, &uFileLen, 4);
encryptfile.Write(bEncryptFileHead, 8);
DWORD dwRead;
UINT uPlainData[2];
UINT uCryptoData[2];
do
{
memset(bBuffer, 0, 8);
dwRead = fileb4.Read(bBuffer, 8);
if ( dwRead > 0 && dwRead <= 8 )
{
memcpy(&uPlainData[0], bBuffer , 4);
memcpy(&uPlainData[1], bBuffer + 4, 4);
encrypt(uPlainData, uCryptoData);
encryptfile.Write(&uCryptoData[0], 4);
encryptfile.Write(&uCryptoData[1], 4);
}
//else if ( 8 > dwRead && 1 <= dwRead )
//{
//
//}
}
while (dwRead > 0);
// Close both files
encryptfile.Close();
fileb4.Close();
try
{
CFile::Remove(pchFileName);
try
{
CFile::Rename( pchEncryptFileName, pchFileName );
}
catch(CFileException* pExRename )
{
printf( "File %s not found %d/n", pchEncryptFileName, pExRename->m_cause);
pExRename->Delete();
}
}
catch (CFileException* pExRemove)
{
printf( "File %s cannot be removed/n", pchFileName);
pExRemove->Delete();
}
return true;
}
//文件解密函數
bool DecryptFile(char *pchFileName, unsigned int uiOffset, void *pMem, unsigned int &uiMemSize)
{
CFile fileb4;
CFile decryptfile;
CFileException e;
char pchDecryptFileName[100];
sprintf(pchDecryptFileName, "$%s", pchFileName);
if( !fileb4.Open( pchFileName, CFile::modeRead | CFile::shareDenyNone, &e ) )
{
printf("%s could not be opened %d/n", pchFileName, e.m_cause);
return false;
}
if ( !decryptfile.Open( pchDecryptFileName, CFile::modeCreate | CFile::modeWrite, &e ))
{
printf("%s could not be created %d/n", pchDecryptFileName, e.m_cause);
fileb4.Close();
return false;
}
UINT uFileLen = fileb4.GetLength();
if ( uFileLen % 8 != 0 )
{
printf("%s 's length mod 8 is not 0/n", pchFileName);
decryptfile.Close();
fileb4.Close();
return false;
}
DWORD dwRead;
BYTE bEncryptFileHead[8];
UINT uDecryptFileLen;
dwRead = fileb4.Read(bEncryptFileHead, 8);
if ( 8 == dwRead )
{
if ( bEncryptFileHead[0] != 'I' )
{
decryptfile.Close();
fileb4.Close();
return false;
}
if ( bEncryptFileHead[1] != 'S' )
{
decryptfile.Close();
fileb4.Close();
return false;
}
if ( bEncryptFileHead[2] != 'D' )
{
decryptfile.Close();
fileb4.Close();
return false;
}
if ( bEncryptFileHead[3] != 'N' )
{
decryptfile.Close();
fileb4.Close();
return false;
}
memcpy(&uDecryptFileLen, bEncryptFileHead + 4, 4 );
if ( uDecryptFileLen + 8 > uFileLen || uDecryptFileLen + 16 < uFileLen )
{
decryptfile.Close();
fileb4.Close();
return false;
}
}
else
{
decryptfile.Close();
fileb4.Close();
return false;
}
fileb4.Seek( uiOffset, CFile::current);
BYTE bBuffer[8];
UINT uPlainData[2];
UINT uCryptoData[2];
UINT uDecryptFileLenHasWrite = 0;
do
{
memset(bBuffer, 0, 8);
dwRead = fileb4.Read(bBuffer, 8);
if ( dwRead > 0 && dwRead <= 8 )
{
memcpy(&uCryptoData[0], bBuffer , 4);
memcpy(&uCryptoData[1], bBuffer + 4, 4);
decrypt(uCryptoData,uPlainData);
if ( uDecryptFileLen - uDecryptFileLenHasWrite >= 8 )
{
decryptfile.Write(&uPlainData[0], 4);
decryptfile.Write(&uPlainData[1], 4);
uDecryptFileLenHasWrite += 8;
}
else if ( uDecryptFileLen - uDecryptFileLenHasWrite >= 4 )
{
decryptfile.Write(&uPlainData[0], 4);
uDecryptFileLenHasWrite += 4;
decryptfile.Write(&uPlainData[1], uDecryptFileLen - uDecryptFileLenHasWrite);
uDecryptFileLenHasWrite = uDecryptFileLen;
}
else
{
decryptfile.Write(&uPlainData[0], uDecryptFileLen - uDecryptFileLenHasWrite);
uDecryptFileLenHasWrite = uDecryptFileLen;
}
}
//else if ( 8 > dwRead && 1 <= dwRead )
//{
//
//}
}
while (dwRead > 0);
// Close both files
decryptfile.Close();
fileb4.Close();
return true;
}
//主函數
void main()
{
if (sizeof(UINT)!=4)
{
printf("RC5 error: UINT has %d bytes./n",sizeof(UINT));
}
UINT j;
char *keystr = "0123456789ABCDEF";
for (j=0; j < KEYSIZE; j++)
{
SetKey((unsigned char)keystr[j]);
}
/* Setup, encrypt, and decrypt */
setup();
////////////////////////////////////////////////////////////////////////
//
EncryptFile("Test.dat");
UINT uMemLen;
DecryptFile("Test.dat", 0, NULL, uMemLen);
return 0;
}