97 lines
2.6 KiB
C
97 lines
2.6 KiB
C
/*
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* Copyright (c) 2017 Stephen Heumann
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*
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* Permission to use, copy, modify, and distribute this software for any
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* purpose with or without fee is hereby granted, provided that the above
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* copyright notice and this permission notice appear in all copies.
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*
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* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
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* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
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* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
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* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
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* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
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* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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*/
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/* Simple toy program to encrypt/decrypt files with AES */
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include "aes.h"
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#define BUFFER_SIZE 0x4000
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unsigned char inbuf[BUFFER_SIZE];
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unsigned char outbuf[BUFFER_SIZE];
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unsigned char iv[16] = "abcdefghijklmnop";
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int main(int argc, char **argv) {
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FILE *infile, *outfile;
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size_t count;
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char *filename;
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struct aes_context context;
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int encrypt;
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if (argc != 4) {
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fprintf(stderr, "wrong number of arguments\n");
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exit(EXIT_FAILURE);
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}
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if (strncmp(argv[1], "-d", 2) == 0) {
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encrypt = 0;
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} else if (strncmp(argv[1], "-e", 2) == 0) {
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encrypt = 1;
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}
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infile = fopen(argv[3], "rb");
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if (infile == NULL) {
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fprintf(stderr, "error opening input file\n");
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return EXIT_FAILURE;
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}
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filename = malloc(strlen(argv[3]) + 5);
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strcpy(filename, argv[3]);
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if (encrypt) {
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strcat(filename, ".aes");
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} else {
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strcat(filename, ".dec");
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}
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outfile = fopen(filename, "wb");
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if (filename == NULL) {
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fprintf(stderr, "error opening output file\n");
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return EXIT_FAILURE;
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}
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memcpy(context.data, iv, 16);
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strncpy(context.key, argv[2], 32);
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aes128_expandkey(&context);
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do {
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count = fread(inbuf, 1, BUFFER_SIZE, infile);
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count = (count + 15) / 16;
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if (encrypt) {
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aes_cbc_encrypt(&context, inbuf, outbuf, count);
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} else {
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aes_cbc_decrypt(&context, inbuf, outbuf, count, iv);
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if (count != 0)
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memcpy(iv, inbuf + (count - 1) * 16, 16);
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}
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count *= 16;
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if (fwrite(outbuf, 1, count, outfile) != count) {
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fprintf(stderr, "error writing file\n");
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goto finish;
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}
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} while (count != 0);
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finish:
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fclose(infile);
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fclose(outfile);
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free(filename);
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}
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