How output text when decrypting a hex? [closed] - c

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i am trying to decrypt the hex string: 0440 04b4 04d0 04d0 04dc 03a0 047c 04dc 04e8 04d0 04b0 03a4
It should once decrypted properly read hello world!
however i cannot get it to output the text. instead i get a list of integers. does anyone have any ideas as to how to fix this?
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
int main (int argc, char **argv)
{
char file_name[25];
char c; //Variable to hold current character
int sz; //Length of file therefore size of array
FILE *fp;
FILE *fw;
int flag = 1;
while (flag)
{
printf("enter the name of the file you wish to decrypt\n");
fgets(file_name, sizeof file_name, stdin); //fgets safer than gets, prevents infinite input
printf("Reading: %s.....\n", file_name); //debug print, can remove
strtok(file_name, "\n"); //fgets potentially leaves \n on file name, this removes
fp=fopen(file_name,"rt"); //file is opened
fw = fopen("revertedfile.txt", "w"); //oens write file
if( fp == NULL ) //checks if file empty/doesn't exist
{
perror("Error while opening the file.\n");
exit(EXIT_FAILURE);
}
//Following code finds length of file by seeking, then resets the file point to the start
fseek(fp, 0L, SEEK_END);
sz = ftell(fp);
printf("Length of file is: %i\n",sz); // Debug print, can delete
fseek(fp, 0L, SEEK_SET);
int data[sz]; //Init array based on file length
int i = 0; //Counter set to 0
while((c=fgetc(fp))!=EOF) //While haven't reached end of file.
{
int ic = (int)c - 200; //minus 200 to the ascii code
//printf("ASCI Code + 100 = %i\n", ic); //debug print
//Could do bit shift before adding to array, I Guess
data[i] = ic; //Add ASCII code to array at i
data[i] = data[i] >> 2; //Bit shift
//Debug print, shows what's happening
int test = data[i];
printf("%i\n", data[i]);
fprintf(fw, "%i\n", data[i]);
//printf("Added %i to the array at point %d\n", test, i);
i++; //Increment pointer for array
}
fclose(fp); //Always close file
fclose(fw); // closes write file
}
return 0;
}
This is the encryption code
printf("enter name of the file you wish to encrypt\n");
fgets(file_name, sizeof file_name, stdin); //fgets safer than gets, prevents infinite input
printf("Reading: %s.....\n", file_name); //debug print, can remove
strtok(file_name, "\n"); //fgets potentially leaves \n on file name, this removes
fp = fopen(file_name,"rt"); //file is opened
fw = fopen("output.txt", "w"); //oens write file
if( fp == NULL ) //checks if file empty/doesn't exist
{
perror("Error while opening the file.\n");
exit(EXIT_FAILURE);
}
//Following code finds length of file by seeking, then resets the file point to the start
fseek(fp, 0L, SEEK_END);
sz = ftell(fp);
printf("Length of file is: %i\n",sz); // Debug print, can delete
fseek(fp, 0L, SEEK_SET);
int data[sz]; //Init array based on file length
int i = 0; //Counter set to 0
while((c=fgetc(fp))!=EOF) //While haven't reached end of file
{
printf("Current char: %c\n",c); //Debug print
int ic = (int)c + 200; //Add 200 to the ascii code
//printf("ASCI Code + 100 = %i\n", ic); //debug print
//Could do bit shift before adding to array, I Guess
data[i] = ic; //Add ASCII code to array at i
data[i] = data[i] << 2; //Bit shift
//Debug print, shows what's happening
int test = data[i];
printf("%04x ", data[i]);
fprintf(fw, "%04x ", data[i]);
//printf("Added %i to the array at point %d\n", test, i);
i++; //Increment pointer for array
}
fclose(fp); //Always close file
fclose(fw); // closes write file
//Debug
int test2 = data[1];
printf("The new file is named output.txt");

Answer 1

If you want to decrypt it, you need to know how it was encrypted (well, that still might not be enough). If you just need to print the character each ASCII code represents, you just need to tell printf that by using %c instead of %i.