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/**
* @file llxorcipher.cpp
* @brief Implementation of LLXORCipher
*
* Copyright (c) 2003-2007, Linden Research, Inc.
*
* The source code in this file ("Source Code") is provided by Linden Lab
* to you under the terms of the GNU General Public License, version 2.0
* ("GPL"), unless you have obtained a separate licensing agreement
* ("Other License"), formally executed by you and Linden Lab. Terms of
* the GPL can be found in doc/GPL-license.txt in this distribution, or
* online at http://secondlife.com/developers/opensource/gplv2
*
* There are special exceptions to the terms and conditions of the GPL as
* it is applied to this Source Code. View the full text of the exception
* in the file doc/FLOSS-exception.txt in this software distribution, or
* online at http://secondlife.com/developers/opensource/flossexception
*
* By copying, modifying or distributing this software, you acknowledge
* that you have read and understood your obligations described above,
* and agree to abide by those obligations.
*
* ALL LINDEN LAB SOURCE CODE IS PROVIDED "AS IS." LINDEN LAB MAKES NO
* WARRANTIES, EXPRESS, IMPLIED OR OTHERWISE, REGARDING ITS ACCURACY,
* COMPLETENESS OR PERFORMANCE.
*/
#include "linden_common.h"
#include "llcrypto.h"
#include "llerror.h"
///----------------------------------------------------------------------------
/// Class LLXORCipher
///----------------------------------------------------------------------------
LLXORCipher::LLXORCipher(const U8* pad, U32 pad_len) :
mPad(NULL),
mHead(NULL),
mPadLen(0)
{
init(pad, pad_len);
}
// Destroys the object
LLXORCipher::~LLXORCipher()
{
init(NULL, 0);
}
LLXORCipher::LLXORCipher(const LLXORCipher& cipher) :
mPad(NULL),
mHead(NULL),
mPadLen(0)
{
init(cipher.mPad, cipher.mPadLen);
}
LLXORCipher& LLXORCipher::operator=(const LLXORCipher& cipher)
{
if(this == &cipher) return *this;
init(cipher.mPad, cipher.mPadLen);
return *this;
}
BOOL LLXORCipher::encrypt(const U8* src, U32 src_len, U8* dst, U32 dst_len)
{
if(!src || !src_len || !dst || !dst_len || !mPad) return FALSE;
U8* pad_end = mPad + mPadLen;
while(src_len--)
{
*dst++ = *src++ ^ *mHead++;
if(mHead >= pad_end) mHead = mPad;
}
return TRUE;
}
BOOL LLXORCipher::decrypt(const U8* src, U32 src_len, U8* dst, U32 dst_len)
{
// xor is a symetric cipher, thus, just call the other function.
return encrypt(src, src_len, dst, dst_len);
}
U32 LLXORCipher::requiredEncryptionSpace(U32 len)
{
return len;
}
void LLXORCipher::init(const U8* pad, U32 pad_len)
{
if(mPad)
{
delete [] mPad;
mPad = NULL;
mPadLen = 0;
}
if(pad && pad_len)
{
mPadLen = pad_len;
mPad = new U8[mPadLen];
if (mPad != NULL)
{
memcpy(mPad, pad, mPadLen); /* Flawfinder : ignore */
}
}
mHead = mPad;
}
#ifdef _DEBUG
// static
BOOL LLXORCipher::testHarness()
{
const U32 PAD_LEN = 3;
const U8 PAD[] = "abc";
const S32 MSG_LENGTH = 12;
const char MESSAGE[MSG_LENGTH+1] = "gesundheight"; /* Flawfinder : ignore */
U8 encrypted[MSG_LENGTH];
U8 decrypted[MSG_LENGTH];
LLXORCipher cipher(PAD, PAD_LEN);
cipher.encrypt((U8*)MESSAGE, MSG_LENGTH, encrypted, MSG_LENGTH);
cipher.decrypt(encrypted, MSG_LENGTH, decrypted, MSG_LENGTH);
if(0 != memcmp((void*)MESSAGE, decrypted, MSG_LENGTH)) return FALSE;
return TRUE;
}
#endif
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