sqlite自定义调用

一、介绍

    自定义sqlite的加解密：使用自定义的读写文件函数替代原接口，实现数据库文件的加解密操作。

二、自定义接口

void XorCrypt(uint8_t* pData, uint32_t dataLen)

{

for (uint32_t i = 0; i < dataLen; i++)

{

pData[i] ^= g_xorKey[ i % sizeof(g_xorKey)]; // 循环使用密钥[reference:6]

}

}

// 自定义 ReadFile

BOOL CSqlite::MyCustom_ReadFile(HANDLE hFile, LPVOID lpBuffer, DWORD nNumberOfBytesToRead, LPDWORD lpNumberOfBytesRead, LPOVERLAPPED lpOverlapped)

{

BOOL ret = ReadFile(hFile, lpBuffer, nNumberOfBytesToRead, lpNumberOfBytesRead, lpOverlapped);

if (ret)

XorCrypt((uint8_t*)lpBuffer, *lpNumberOfBytesRead);

return ret;

}

// 自定义 WriteFile

BOOL CSqlite::MyCustom_WriteFile(HANDLE hFile, LPCVOID lpBuffer, DWORD nNumberOfBytesToWrite, LPDWORD lpNumberOfBytesWritten, LPOVERLAPPED lpOverlapped)

{

memcpy(m, lpBuffer, nNumberOfBytesToWrite);

XorCrypt((uint8_t*)m, nNumberOfBytesToWrite);

BOOL ret = WriteFile(hFile, m, nNumberOfBytesToWrite, lpNumberOfBytesWritten, lpOverlapped);

return ret;

}

三、注册接口

sqlite3_vfs* pVfs = sqlite3_vfs_find("win32");

if (pVfs == NULL)

return;

if (pVfs->xSetSystemCall)

{

pVfs->xSetSystemCall(pVfs, "ReadFile", (sqlite3_syscall_ptr)MyCustom_ReadFile);

pVfs->xSetSystemCall(pVfs, "WriteFile", (sqlite3_syscall_ptr)MyCustom_WriteFile);

}

四、结论

    示例程序会将sqlite数据库文件使用自定义算法保存，且使用自定义方法解密，实现数据库加解密的自主控制。

    sqlite还有很多其他可自定义调用，根据需要自行设计。