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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