cryptogear encryption algorithm

[flexy]

hey, im very new to c++ and i keep getting errors when i try to run this code in visual c++ , im also unsure if it should be a win console application or a win desktop application? errors below are from running it in console app



#include <windows.h> // For memcpy
#include "CryptoGear.h"


// Constructor.
CCryptoGear::CCryptoGear(unsigned char* pKey, unsigned int lenKey, unsigned char ModeOfOperation, unsigned char InitializationVector)
{
Initialize(pKey, lenKey, ModeOfOperation, InitializationVector);
}


// Overloaded costructor with no arguments.
// Must manually initialize keystream.
CCryptoGear::CCryptoGear()
{}


// Cipher Initialization.
// Generates keystream and set mode of operation.
void CCryptoGear::Initialize(unsigned char* pKey, unsigned int lenKey, unsigned char ModeOfOperation,unsigned char InitializationVector)
{
m_ModeOfOperation = ModeOfOperation;

unsigned int i;

for (i = 0; i < m_lenKeystream; i++)
{
m_KeyStream[i] = i + InitializationVector;
}

for (i = 0; i < m_lenKeystream; i++)
{
// xor initial keystream element value(0 - 255) with corresponding byte from key offset
m_KeyStream[i] ^= (lenKey + pKey[i % lenKey]) % 256;
}
}


void CCryptoGear::Encrypt(unsigned char pData[], unsigned long lenData)
{
unsigned long Offset;
unsigned char KeyStream[m_lenKeystream];

//Create a local copy of the original KeyStream.
memcpy(KeyStream, m_KeyStream, m_lenKeystream * sizeof(unsigned char));

// Calculate padding
unsigned char extra = lenData % 4;
// If plain-text data size is not a multiple of block size,
// then we must add a temporary padding (will be removed after finishing encrypting)
if (extra)
{
extra = 4 - extra;
lenData += extra;
pData = (unsigned char*)realloc(pData, lenData);
}

//Encrypt the data.
for (Offset = 0; Offset < lenData; Offset = Offset + 4)
{
pData[Offset] ^= KeyStream[Offset % m_lenKeystream];
pData[(Offset + 1) % lenData] += (pData[Offset] + KeyStream[ (Offset + 1) % m_lenKeystream]) % 256;
pData[(Offset + 2) % lenData] += (pData[(Offset + 1) % lenData] - KeyStream[ (Offset + 2) % m_lenKeystream]) % 256;
pData[(Offset + 3) % lenData] += (pData[(Offset + 2) % lenData] ^ KeyStream[ (Offset + 3) % m_lenKeystream]) % 256;

if (m_ModeOfOperation == MODE_CBC)
{
if (Offset > 0)
{
// xor block with previous block.
pData[Offset] ^= (pData[(Offset - 4) % lenData]) % 256;
pData[(Offset + 1) % lenData] ^= (pData[(Offset - 3) % lenData]) % 256;
pData[(Offset + 2) % lenData] ^= (pData[(Offset - 2) % lenData]) % 256;
pData[(Offset + 3) % lenData] ^= (pData[(Offset - 1) % lenData]) % 256;
}

// keystream elements used in this block are shifted.
// This way on next key round the corresponding keystream byte will be different.
for (unsigned char i = 0; i < 4; i++)
{
KeyStream[(Offset + i) % m_lenKeystream] += pData[(Offset + i) % lenData] % 256;
}
}
}

// Remove padding.
if (extra)
{
lenData -= extra;
pData = (unsigned char*)realloc(pData, lenData);
}
}


void CCryptoGear::Decrypt(unsigned char pData[], unsigned long lenData)
{
unsigned char KeyStream[m_lenKeystream];
unsigned long Offset;
unsigned char a, b, c, d;
unsigned char e, f, g, h;
unsigned char i, j, k;

//Create a local copy of the original keystream.
memcpy(KeyStream, m_KeyStream, m_lenKeystream * sizeof(unsigned char));

// Calculate padding
unsigned char extra = lenData % 4;
// If data size is not a multiple of block size,
// then we must temporarely add padding (will be removed after finishing decryption)
if (extra)
{
extra = 4 - extra;
lenData += extra;
pData = (unsigned char*)realloc(pData, lenData);
}

//Decrypt the data.
for (Offset = 0; Offset < lenData; Offset = Offset + 4)
{
if (m_ModeOfOperation == MODE_CBC)
{
// Save original encrypted bytes, used for key shifting later
a = pData[Offset];
b = pData[(Offset + 1) % lenData];
c = pData[(Offset + 2) % lenData];
d = pData[(Offset + 3) % lenData];

// Do from second cycle
if (Offset > 0)
{
// xor block with previous block
pData[Offset] ^= e % 256;
pData[(Offset + 1) % lenData] ^= f % 256;
pData[(Offset + 2) % lenData] ^= g % 256;
pData[(Offset + 3) % lenData] ^= h % 256;
}

// Store encrypted bytes of this block for next cycle
e = a;
f = b;
g = c;
h = d;
}

// Save xored bytes (or original encrypted bytes if we are using ECB).
// With those we can shift back keystream operations and obtain clear-text.
i = pData[Offset];
j = pData[(Offset + 1) % lenData];
k = pData[(Offset + 2) % lenData];

pData[Offset] ^= KeyStream[Offset % m_lenKeystream];
pData[(Offset + 1) % lenData] -= (i + KeyStream[(Offset + 1) % m_lenKeystream]) % 256;
pData[(Offset + 2) % lenData] -= (j - KeyStream[(Offset + 2) % m_lenKeystream]) % 256;
pData[(Offset + 3) % lenData] -= (k ^ KeyStream[(Offset + 3) % m_lenKeystream]) % 256;

if (m_ModeOfOperation == MODE_CBC)
{
// Values of KeyStream elements used in this block are modified.
// This way on each key round the corresponding key byte will be different.
KeyStream[Offset % m_lenKeystream] += a;
KeyStream[(Offset + 1) % m_lenKeystream] += b;
KeyStream[(Offset + 2) % m_lenKeystream] += c;
KeyStream[(Offset + 3) % m_lenKeystream] += d;
}
}

// Remove padding.
if (extra)
{
lenData -= extra;
pData = (unsigned char*)realloc(pData, lenData);
}
}




iv added the header to the project ect, these are the errors i get

1. E1696 cannot open source file "CryptoGear.h" ConsoleApplication3 c:\Users\username\source\repos\ConsoleApplication3\ConsoleApplication3\ConsoleApplication3.cpp 6

2.E0276 name followed by '::' must be a class or namespace name ConsoleApplication3 c:\Users\username\source\repos\ConsoleApplication3\ConsoleApplication3\ConsoleApplication3.cpp 10

3.E0020 identifier "Initialize" is undefined ConsoleApplication3 c:\Users\username\source\repos\ConsoleApplication3\ConsoleApplication3\ConsoleApplication3.cpp 12

4.E0276 name followed by '::' must be a class or namespace name ConsoleApplication3 c:\Users\username\source\repos\ConsoleApplication3\ConsoleApplication3\ConsoleApplication3.cpp 18

5. E0020 identifier "m_ModeOfOperation" is undefined ConsoleApplication3 c:\Users\username\source\repos\ConsoleApplication3\ConsoleApplication3\ConsoleApplication3.cpp 26

and about 20 more errors, if someone could get back to me with advise id appreciate it.

[icy1]

In general you want to wrap all code in [ code ] ... [ /code ] tags (no spaces between brackets).

In this case the problem is more about including the header. Guessing the header is not in same directory as the .cpp , or is not in a directory pulled in by included directories.

[jonnin]

you can explicitly add the folder where the headers are to the project under the project area. That is probably the best approach here.

[flexy]

thanks alot guys it was the header youre right :) thanks i appreciate it!