ghost/bitcryto.cpp at master · ghostceo/ghost · GitHub

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// 模块描述：简单的移位加密算法
//----------------------------------------------------------------*/
#include <string>

#include "bitcryto.h"

using std::string;


CBitCryto::CBitCryto(const char* szKey) : m_strKey(szKey), m_nIdx(0)
{
}

CBitCryto::~CBitCryto()
{
}

unsigned char CBitCryto::Encode(unsigned char c)
{
    if(m_nIdx >= m_strKey.size())
    {
        m_nIdx = 0;
    }
    unsigned short k = (unsigned short)m_strKey[m_nIdx];
    ++m_nIdx;

    unsigned char c2 = (unsigned char)((k + (unsigned short)c) & 0xff);

    return c2;
}

unsigned char CBitCryto::Decode(unsigned char c)
{
    if(m_nIdx >= m_strKey.size())
    {
        m_nIdx = 0;
    }
    short k = (short)m_strKey[m_nIdx];
    ++m_nIdx;

    short c2 = (short)c - k;
    if(c2 < 0)
    {
        c2 += 256;
    }

    return (unsigned char)c2;
}