This program will take a PPM image and will encrypt/decrypt when supplied with a key The goal is to fix the errors and decrypt the secret PPM image. This will use secret.ppm as the source, key as the crypto key, and decrypted.ppm as the location of the generated image. You will run into segmentation faults and memory leaks. Fix these and then attempt to decrypt the secret message! Errors will be in: Lab3.c main() method, crypto.c read_image() method, crypto.c sym_crypt() method

Objectives: Fix compiler errors/warnings. The comments will show what sections have errors. Fix segmentation faults/plug memory leaks using GDB and Valgrind. Run decryption program to decrypt secrets.ppm. Finally, decrypt the number hidden in the image.

XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX

// Lab3.c //

#include "stdio.h"

#include "stdlib.h"

#include "crypto.h"

int main(int argc, char const *argv[]) {

FILE* image_file = fopen(argv[1], "r");

FILE* key_file = fopen(argv[2], "r");

FILE* out_image = fopen(argv[3], "w");

// Read image

header_t header;

img_t img;

read_header(image_file, header);

read_image(image_file, &img, &header);

// Read secret key

int seed;

read_seed(key_file, *seed);

sp_rand(eed);

/** NO ERROR HERE **/

printf("Encrypt[1] or Decrypt[2]? ");

int choice;

while(true) {

scanf("%d",&choice);

if(choice == 1 || choice == 2) {

sym_crypt(out_image, &header, &img, choice);

break;

} else {

printf("Please enter 1 or 2 ");

}

}

/********************/

fclose(image_file);

fclose(key_file);

fclose(out_image);

return 0;

}

XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX

// crypto.h //

#ifndef CRYPTO_H

#define CRYPTO_H value

#include "stdio.h"

#include "stdlib.h"

#include "limits.h"

#include "stdbool.h"

extern int P_RAND_SEED;

typedef struct header_t {

char* type;

int w, h, cs;

} header_t;

typedef struct pixel_t {

unsigned char r,g,b;

} pixel_t;

typedef struct img_t {

pixel_t** data;

} img_t;

void read_header(FILE* in_img, header_t* header);

void read_image(FILE* in_img, img_t* image, header_t* header);

void read_seed(FILE* seed_file, int* seed);

void sym_crypt(FILE* out_img, header_t* header, img_t* image, int mode);

// Dumb random number generator

void sp_rand(unsigned int seed);

unsigned int p_rand(unsigned int init);

#endif

XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX

// crypto.c //

#include "crypto.h"

int P_RAND_SEED = 1;

/** NO ERRORS HERE! **/

void read_header(FILE* in_img, header_t* header) {

header->type = malloc(sizeof(char)*3);

fscanf(in_img, "%s ", header->type);

fscanf(in_img, "%d %d ", &header->w, &header->h);

fscanf(in_img, "%d ", &header->cs);

printf("Header: %s %d %d %d ", header->type, header->w, header->h, header->cs);

}

/********************/

/** Could be errors... **/

void read_image(FILE* input, img_t* image, header_t* header) {

int row, col;

image->data = malloc(sizeof(pixel_t*) * header.h);

for(row = 0; row h; row++) {

image->data[row] = malloc(sizeof(pixel_t) * header->w * 3);

for(; col w; col++) {

pixel_t pix

fscanf(input, "%c%c%c", &pix.r, &pix.g, &pix.b);

image.data[row][col] = pix;

}

}

}

/** NO ERRORS HERE! **/

void read_seed(FILE* seed_file, int* seed) {

fscanf(seed_file, "%d", seed);

}

/** Could be errors... **/

void sym_crypt(FILE* output, header_t* header, img_t* image, int mode) {

// Write header of PPM to files

/** NO ERRORS HERE! **/

fprintf(output, "%s %d %d %d ", header->type, header->w, header->h, header->cs);

/*********************/

// Encrypt or Decrypt! Could be errors... //

int row, col;

switch (mode) {

case 1:

printf("Encrypt ", );

for(row = 0; row h; row++) {

for(col = 0; col w; col++) {

int swap_row = p_rand(row*row) % header.h;

int swap_col = p_rand(col*col) % header->w;

pixel_t swap = image->data[row][col];

image->data[row][col] = image->data[swap_row][swap_col];

image->data[swap_row][swap_col] = swap;

}

} break;

case 2:

printf("Decrypt ");

for(row = header->h-1; row >= 0; row--) {

for(; col >= 0; col--) {

int swap_row = p_rand(row*row) % header->h;

int swap_col = p_rand(col*col) % header->w;

pixel_t swap = image->data[row][col];

image->data[row][col] = image->data[swap_row][swap_col];

image->data[swap_row][swap_col] = swap;

}

} break;

default: break;

}

/** NO ERRORS HERE! **/

for(row = 0; row h; row++) {

for(col = 0; col w; col++) {

pixel_t pix = image->data[row][col];

fprintf(output, "%c%c%c", pix.r, pix.g, pix.b);

}

}

/********************/

}

/** NO ERRORS HERE! **/

void sp_rand(unsigned int seed) {

P_RAND_SEED = seed;

}

/********************/

/** NO ERRORS HERE! **/

unsigned int p_rand(unsigned int init) {

return (P_RAND_SEED*init) % INT_MAX;

}

/********************/

XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX

Key: 22695477

XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX

PPM Image