1/*
2 * aes_calc.c
3 *
4 * A simple AES calculator for generating AES encryption values
5 *
6 * David A. McGrew
7 * Cisco Systems, Inc.
8 */
9
10/*
11
12 Example usage (with first NIST FIPS 197 test case):
13
14[sh]$ test/aes_calc 000102030405060708090a0b0c0d0e0f 00112233445566778899aabbccddeeff -v
15 plaintext:      00112233445566778899aabbccddeeff
16 key:            000102030405060708090a0b0c0d0e0f
17 ciphertext:     69c4e0d86a7b0430d8cdb78070b4c55a
18
19 */
20
21#include "aes.h"
22#include <stdio.h>
23#include <string.h>
24
25void
26usage(char *prog_name) {
27  printf("usage: %s <key> <plaintext> [-v]\n", prog_name);
28  exit(255);
29}
30
31#define AES_KEY_LEN 16
32
33int
34main (int argc, char *argv[]) {
35  v128_t data, key;
36  aes_expanded_key_t exp_key;
37  int len;
38  int verbose;
39
40  if (argc == 3) {
41    /* we're not in verbose mode */
42    verbose = 0;
43  } else if (argc == 4) {
44    if (strncmp(argv[3], "-v", 2) == 0) {
45      /* we're in verbose mode */
46      verbose = 1;
47    } else {
48      /* unrecognized flag, complain and exit */
49      usage(argv[0]);
50    }
51  } else {
52    /* we've been fed the wrong number of arguments - compain and exit */
53    usage(argv[0]);
54  }
55
56  /* read in key, checking length */
57  if (strlen(argv[1]) > AES_KEY_LEN*2) {
58    fprintf(stderr,
59	    "error: too many digits in key "
60	    "(should be %d hexadecimal digits, found %u)\n",
61	    AES_KEY_LEN*2, (unsigned)strlen(argv[1]));
62    exit(1);
63  }
64  len = hex_string_to_octet_string((char *)&key, argv[1], AES_KEY_LEN*2);
65  /* check that hex string is the right length */
66  if (len < AES_KEY_LEN*2) {
67    fprintf(stderr,
68	    "error: too few digits in key "
69	    "(should be %d hexadecimal digits, found %d)\n",
70	    AES_KEY_LEN*2, len);
71    exit(1);
72  }
73
74  /* read in plaintext, checking length */
75  if (strlen(argv[2]) > 16*2) {
76    fprintf(stderr,
77	    "error: too many digits in plaintext "
78	    "(should be %d hexadecimal digits, found %u)\n",
79	    16*2, (unsigned)strlen(argv[2]));
80    exit(1);
81  }
82  len = hex_string_to_octet_string((char *)(&data), argv[2], 16*2);
83  /* check that hex string is the right length */
84  if (len < 16*2) {
85    fprintf(stderr,
86	    "error: too few digits in plaintext "
87	    "(should be %d hexadecimal digits, found %d)\n",
88	    16*2, len);
89    exit(1);
90  }
91
92  if (verbose) {
93    /* print out plaintext */
94    printf("plaintext:\t%s\n", octet_string_hex_string((uint8_t *)&data, 16));
95  }
96
97  /* encrypt plaintext */
98  aes_expand_encryption_key(&key, exp_key);
99
100  aes_encrypt(&data, exp_key);
101
102  /* write ciphertext to output */
103  if (verbose) {
104    printf("key:\t\t%s\n", v128_hex_string(&key));
105    printf("ciphertext:\t");
106  }
107  printf("%s\n", v128_hex_string(&data));
108
109  return 0;
110}
111
112