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
25 void
usage(char * prog_name)26 usage(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
33 int
main(int argc,char * argv[])34 main (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