Here is an overview of how we will encrypt/decrypt an unicode file
Encryption:
1. Open the file as binary mode and read the content of file to a byte array.
2. Encrypt the byte array.
3. Write the byte array to a file.
Decryption:
1. Open the encrypted file as binary mode and read content of the file to a byte array.
2. Decrypt the byte array.
3. Write the byte array to a file.
The encryption and decryption functions are:
void EncryptBytes
(
unsigned char* pByte, // Bytes passed in, encrypted bytes passed out.
int iSize, // Size of the byte array
int* pKey // Encrypting key. (in/out)
)
{
int ii = 0;
unsigned char iNew = 0;
for(ii = 0; ii < iSize; ii++)
{
// Encrypt the character.
iNew = pByte[ii] ^ ((*pKey >> 8));
*pKey = ((iNew + *pKey) & 0xFFFF)*EncryptConst1 - EncryptConst2;
pByte[ii] = iNew;
}
}
void DecryptBytes
(
unsigned char* pByte, // Bytes passed in, decrypted bytes passed out.
int iSize, // Size of the byte array
int* pKey // Encrypting key. (in/out)
)
{
int ii = 0;
unsigned char iNew = 0, iVal;
for(ii = 0; ii < iSize; ii++)
{
iVal = pByte[ii];
iNew = iVal ^ ((*pKey >> 8));
*pKey = ((iVal + *pKey) & 0xFFFF)*EncryptConst1 - EncryptConst2;
pByte[ii] = iNew;
}
}
