Ben Tiny Encryption.

hi, this is some code I been working on since yesterday to encrypt files. I posting here to find out how I can improve it or make it stronger, it still uses xor like in simple encryption, but I made a table array to hold the password unto 256 bytes, and then done some basic maths on the values. to make it seem random. I did this to avoid any repeated runs of the same, I am only starting to get into encryption so this is one of my first try's. anyway tell us what you think.

Code:

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#include <iostream>
#include <time.h>
using namespace std;

unsigned int pbox[256];

void Abort(int id, char*msg){

        //Bens Tiny Encription.
        printf("BTE By Benjamin George\nEasy encrypt your private data.\n\n");

        switch(id){
                case 0:
                        printf("Syntax: FileToEncrypt OutputFile Password\n");
                        printf(" bcrypt.exe private.txt private.enc password\n");
                        break;
                case 1:
                        printf("Error reading source filename:\n ");
                        printf(msg);
                        break;
                case 2:
                        printf("Error writeing output filename:\n ");
                        printf(msg);
                        break;
                case 3:
                        printf("Password is required.");
                        break;
        }
        printf("\n");
}

void PrepPws(char *pws){
        int I = 0;
        char c = 0;
        unsigned phash = 0;

        //Build hash sum from original password.
        while(I < 256){
                //Get single char from password.
                c = pws[I % strlen(pws)];
                phash+= (rand() + c) % 256;
                //INC Counter.
                I++;
        }

        I = 0;

        //Set random starting seed.
        srand(phash);

        //Here were we randomize our password so it harder and not so repeated.
        while(I < 256){
                //Get simgle char value.
                c = pws[I % strlen(pws)];
                //Get a nise large random number.
                phash =(phash + rand() + c);
                //Store the value, remmber we must mod by 256, so we get a vaild char code.
                pbox[I] = (phash % 256);
                //INC Counter.
                I++;
        }
}

int main(int argc, char *argv[]){
        FILE *fin,*fout;
        unsigned int bCount = 0;
        unsigned char ch = 0;
        unsigned pValueIdx = 0;
        char bXor = 0;

        if(argc != 4){
                Abort(0,"");
                return 0;
        }

        //Open source input file.
        fin = fopen(argv[1],"rb");
        //Check if the file was opened.
        if(!fin){
                Abort(1,argv[1]);
                return 1;
        }

        //Create output source file.
        fout = fopen(argv[2],"wb");

        //Check if output file was created.
        if(!fout){
                Abort(2,argv[2]);
                return 2;
        }

        //Get the key.
        if(strlen(argv[3]) == 0){
                Abort(3,"");
                return 3;
        }

        //Prep the password.
        PrepPws(argv[3]);

        while(!feof(fin)){
                //Read char.
                ch = fgetc(fin);
                //While not end of file write data to output source file.
                if(!feof(fin)){
                        pValueIdx = (rand() % 256);
                        //Crypt the byte with bXor
                        bXor = (pbox[pValueIdx] ^ ch);
                        //Write byte to file.
                        fputc(bXor,fout);
                }
                //File byte counter.
                bCount++;
        }

        //Clear pbox.
        for(int i = 0;i<256;i++){
                //Clear each slot.
                pbox[i] = 0;
        }

        //Close output file.
        fclose(fout);
        //Close input source file.
        fclose(fin);

        return 4;
}

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