aes.h revision 5738f83aeb59361a0a2eda2460113f6dc9194271 
1/*
2 ---------------------------------------------------------------------------
3 Copyright (c) 1998-2008, Brian Gladman, Worcester, UK. All rights reserved.
4
5 LICENSE TERMS
6
7 The redistribution and use of this software (with or without changes)
8 is allowed without the payment of fees or royalties provided that:
9
10  1. source code distributions include the above copyright notice, this
11     list of conditions and the following disclaimer;
12
13  2. binary distributions include the above copyright notice, this list
14     of conditions and the following disclaimer in their documentation;
15
16  3. the name of the copyright holder is not used to endorse products
17     built using this software without specific written permission.
18
19 DISCLAIMER
20
21 This software is provided 'as is' with no explicit or implied warranties
22 in respect of its properties, including, but not limited to, correctness
23 and/or fitness for purpose.
24 ---------------------------------------------------------------------------
25 Issue 09/09/2006
26
27 This is an AES implementation that uses only 8-bit byte operations on the
28 cipher state.
29 */
30
31#ifndef AES_H
32#define AES_H
33
34#if 1
35#  define AES_ENC_PREKEYED  /* AES encryption with a precomputed key schedule  */
36#endif
37#if 1
38#  define AES_DEC_PREKEYED  /* AES decryption with a precomputed key schedule  */
39#endif
40#if 1
41#  define AES_ENC_128_OTFK  /* AES encryption with 'on the fly' 128 bit keying */
42#endif
43#if 1
44#  define AES_DEC_128_OTFK  /* AES decryption with 'on the fly' 128 bit keying */
45#endif
46#if 1
47#  define AES_ENC_256_OTFK  /* AES encryption with 'on the fly' 256 bit keying */
48#endif
49#if 1
50#  define AES_DEC_256_OTFK  /* AES decryption with 'on the fly' 256 bit keying */
51#endif
52
53#define N_ROW                   4
54#define N_COL                   4
55#define N_BLOCK   (N_ROW * N_COL)
56#define N_MAX_ROUNDS           14
57
58typedef unsigned char uint_8t;
59
60typedef uint_8t return_type;
61
62/*  Warning: The key length for 256 bit keys overflows a byte
63    (see comment below)
64*/
65
66typedef uint_8t length_type;
67
68typedef struct
69{   uint_8t ksch[(N_MAX_ROUNDS + 1) * N_BLOCK];
70    uint_8t rnd;
71} aes_context;
72
73/*  The following calls are for a precomputed key schedule
74
75    NOTE: If the length_type used for the key length is an
76    unsigned 8-bit character, a key length of 256 bits must
77    be entered as a length in bytes (valid inputs are hence
78    128, 192, 16, 24 and 32).
79*/
80
81#if defined( AES_ENC_PREKEYED ) || defined( AES_DEC_PREKEYED )
82
83return_type aes_set_key( const unsigned char key[],
84                         length_type keylen,
85                         aes_context ctx[1] );
86#endif
87
88#if defined( AES_ENC_PREKEYED )
89
90return_type aes_encrypt( const unsigned char in[N_BLOCK],
91                         unsigned char out[N_BLOCK],
92                         const aes_context ctx[1] );
93
94return_type aes_cbc_encrypt( const unsigned char *in,
95                         unsigned char *out,
96                         int n_block,
97                         unsigned char iv[N_BLOCK],
98                         const aes_context ctx[1] );
99#endif
100
101#if defined( AES_DEC_PREKEYED )
102
103return_type aes_decrypt( const unsigned char in[N_BLOCK],
104                         unsigned char out[N_BLOCK],
105                         const aes_context ctx[1] );
106
107return_type aes_cbc_decrypt( const unsigned char *in,
108                         unsigned char *out,
109                         int n_block,
110                         unsigned char iv[N_BLOCK],
111                         const aes_context ctx[1] );
112#endif
113
114/*  The following calls are for 'on the fly' keying.  In this case the
115    encryption and decryption keys are different.
116
117    The encryption subroutines take a key in an array of bytes in
118    key[L] where L is 16, 24 or 32 bytes for key lengths of 128,
119    192, and 256 bits respectively.  They then encrypts the input
120    data, in[] with this key and put the reult in the output array
121    out[].  In addition, the second key array, o_key[L], is used
122    to output the key that is needed by the decryption subroutine
123    to reverse the encryption operation.  The two key arrays can
124    be the same array but in this case the original key will be
125    overwritten.
126
127    In the same way, the decryption subroutines output keys that
128    can be used to reverse their effect when used for encryption.
129
130    Only 128 and 256 bit keys are supported in these 'on the fly'
131    modes.
132*/
133
134#if defined( AES_ENC_128_OTFK )
135void aes_encrypt_128( const unsigned char in[N_BLOCK],
136                      unsigned char out[N_BLOCK],
137                      const unsigned char key[N_BLOCK],
138                      uint_8t o_key[N_BLOCK] );
139#endif
140
141#if defined( AES_DEC_128_OTFK )
142void aes_decrypt_128( const unsigned char in[N_BLOCK],
143                      unsigned char out[N_BLOCK],
144                      const unsigned char key[N_BLOCK],
145                      unsigned char o_key[N_BLOCK] );
146#endif
147
148#if defined( AES_ENC_256_OTFK )
149void aes_encrypt_256( const unsigned char in[N_BLOCK],
150                      unsigned char out[N_BLOCK],
151                      const unsigned char key[2 * N_BLOCK],
152                      unsigned char o_key[2 * N_BLOCK] );
153#endif
154
155#if defined( AES_DEC_256_OTFK )
156void aes_decrypt_256( const unsigned char in[N_BLOCK],
157                      unsigned char out[N_BLOCK],
158                      const unsigned char key[2 * N_BLOCK],
159                      unsigned char o_key[2 * N_BLOCK] );
160#endif
161
162#endif
163