String parser review
First of all separate code into header (.hpp) and implementation file (.cpp)

Header : (my_header.hpp)

#ifndef MY_HEADER
#define MY_HEADER
class KeyInputParser
{
public:
    KeyInputParser  () // there is no need for funcName (void) in C++
    ~KeyInputParser () // that is neccessary only for C
    char* DIV;
    char* GKY;
    char* UID;
    void SetKeyString (const char* str);
    // Progress bewteen div, gky and uid
    char* Progress (char* previous);
    // Get data between &lt;&gt;
    void ExtractField (char* small, char* big);
};
#endif


Implementation : (my_code.cpp)

#include &lt;cstring&gt; 
#include "my_header.hpp"

KeyInputParser::KeyInputParser () 
{
    //DIV will always be 16bytes... but it is either not required
    DIV = new char[32];
    //uid will ALWAYS be 7 bytes and is required
    UID = new char[14];
}

KeyInputParser::~KeyInputParser () 
{
    delete[] DIV;
    delete[] GKY;
    delete[] UID;
}

char* KeyInputParser::Progress (char* previous) 
{
    char* arr = (char*) memchr (previous, '&gt;', strlen (previous));
    arr++;
    return arr;
}

void KeyInputParser::ExtractField (char* small, char* big) 
{
    for(int i = 0; i &lt; strlen (small); i++)
    {
        if(small [i] == '&lt;')
        {
            memcpy (big, small, i);
            big[i] = '\0';
            break;
        }
    }
}
void KeyInputParser::SetKeyString (const char* str) 
{
    char* div = Progress (str);
    char* gky = Progress (div);
    char* uid = Progress (gky);

    ExtractField (div, DIV);
    // Code for GKY will be copied due to allocation
    // It might be possible to fix it to be used with ExtractField function
    for(int i = 0; i &lt; strlen (gky); i++)
    {
        if(gky[i] == '&lt;')
        {
            GKY = new char[i+1];
            memcpy(GKY, gky, i);
            GKY[i] = '\0';
            break;
        }
    }
    ExtractField (uid, UID);
}


This is just a rough refactoring of your code.
The thing number one that will need to be fixed is to drop all those C string functions and use std::string instead.

I did not test the code so I cannot guarantee that it will work but this is how it should look like. Hope I helped :)