#include <stdio.h>
#include <stdlib.h>
#include <time.h>
#include <string.h>


int generate_mask(int len_c,unsigned char *mask)
{
    srand (time(NULL));
    int i;
    for(i=0;i<len_c;++i)
        mask[i]=rand()% 255 + 1;   // randomn key between 1 and 255, extented ascii

mask[len_c]='\0';

    return 0;
}


int generate_encryption(unsigned char *cipher,unsigned char *mask,unsigned char *crypted,int len_c)
{

    int i;
    for(i=0;i<len_c;++i)
       {
           if( (mask[i]+cipher[i]) > 255 ) // is the result superior to the table ?
                crypted[i]=(mask[i]+cipher[i]) % 255; // if yes, we make a modulo
           else
                crypted[i]=mask[i]+cipher[i];
       }

    crypted[len_c]='\0';

    return 0;
}

int main(int argc, char *argv[])
{
if(argc == 2)
   {
    int len_c=strlen(argv[1]);
    unsigned char *mask=(unsigned char *)malloc(sizeof(char)*len_c+1);
    unsigned char *crypted=(unsigned char *)malloc(sizeof(char)*len_c+1);


    generate_mask(len_c,mask);

    generate_encryption((unsigned char *)argv[1],mask,crypted,len_c);

    printf("Message: %s\n Mask: %s\n Crypted: %s\n",argv[1],mask,crypted);
    free(mask);
    free(crypted);
   }

else
    fprintf(stderr,"Usage: ./<executable> <text to encrypt>");