woody-woodpacker/srcs/encrypt.c

#include "../includes/woody.h"
#include "../includes/rsa.h"

unsigned long encrypt(char *file, unsigned long int offset, unsigned long int size, rsa_t rsa)
{
	size_t padded_len = size * sizeof(char) * 33 / sizeof(uint32_t) / 32 + 1; // every 32 octet one padding octet, plus one for the remainder (uses too much memory for size % 128 == 0 but fuck you)
	uint32_t *padded = (uint32_t *)malloc(sizeof(uint32_t) * padded_len);
	for (size_t i = 0; i < padded_len; i++) {
		padded[padded_len] = 0;
	}
	(void)rsa;
	size_t i = 0;
	while (i < size) {
		size_t j = 0;
		while (j < 8) {
			size_t bit_index = i * 8 * sizeof(char) + j;
			//printf("bit_index : %ld\n", bit_index);
			padded[bit_index / 31] += (1 & (file[bit_index / 8] >> j)) << (bit_index % 31);
			j++;
		}
		//file[offset + i] = file[offset + i] - 1;
		++i;
	}
	for (size_t i = 0; i < padded_len; i++) {
		printf("block           : %x\n", padded[i]);//, padded[i]);
		padded[i] = pow_mod(padded[i] + 42 + i, 11317, rsa.n);
		printf("encrypted block : %x\n\n", padded[i]);//, padded[i]);
		//printf("decipher block  : %lu (%lx)\n", pow_mod(padded[i], rsa.d, rsa.n) - 42 - i, pow_mod(padded[i], rsa.d, rsa.n) - 42 - i);
	}
	memcpy(&file[offset], padded, padded_len * sizeof(uint32_t));
	printf("\nENCRYPTION : \n");
	printf("	File encrypted from %ld (%lx) to %ld (%lx)\n", offset, offset, offset + size, offset + size);
	printf("	Size of encryption = %ld (%lx)\n", size, size);
	printf("	Size of padded encryption = %ld (%lx)\n", padded_len * sizeof(uint32_t), padded_len * sizeof(uint32_t));
	printf("\n");
	return offset + padded_len * sizeof(uint32_t);
}