1/*********************************************************************
2* Filename: aes.c
3* Author: Brad Conte (brad AT bradconte.com)
4* Copyright:
5* Disclaimer: This code is presented "as is" without any guarantees.
6* Details: This code is the implementation of the AES algorithm and
7 the CTR, CBC, and CCM modes of operation it can be used in.
8 AES is, specified by the NIST in in publication FIPS PUB 197,
9 availible at:
10 * http://csrc.nist.gov/publications/fips/fips197/fips-197.pdf .
11 The CBC and CTR modes of operation are specified by
12 NIST SP 800-38 A, available at:
13 * http://csrc.nist.gov/publications/nistpubs/800-38a/sp800-38a.pdf .
14 The CCM mode of operation is specified by NIST SP80-38 C, available at:
15 * http://csrc.nist.gov/publications/nistpubs/800-38C/SP800-38C_updated-July20_2007.pdf
16*********************************************************************/
17
18/*************************** HEADER FILES ***************************/
19#include <stdlib.h>
20#include <memory.h>
21#include "aes.h"
22
23#include <stdio.h>
24#include <string.h>
25
26/****************************** MACROS ******************************/
27// The least significant byte of the word is rotated to the end.
28#define KE_ROTWORD(x) (((x) << 8) | ((x) >> 24))
29
30#define TRUE 1
31#define FALSE 0
32
33/**************************** DATA TYPES ****************************/
34#define AES_128_ROUNDS 10
35#define AES_192_ROUNDS 12
36#define AES_256_ROUNDS 14
37
38/*********************** FUNCTION DECLARATIONS **********************/
39void ccm_prepare_first_ctr_blk(BYTE counter[], const BYTE nonce[], int nonce_len, int payload_len_store_size);
40void ccm_prepare_first_format_blk(BYTE buf[], int assoc_len, int payload_len, int payload_len_store_size, int mac_len, const BYTE nonce[], int nonce_len);
41void ccm_format_assoc_data(BYTE buf[], int *end_of_buf, const BYTE assoc[], int assoc_len);
42void ccm_format_payload_data(BYTE buf[], int *end_of_buf, const BYTE payload[], int payload_len);
43
44/**************************** VARIABLES *****************************/
45// This is the specified AES SBox. To look up a substitution value, put the first
46// nibble in the first index (row) and the second nibble in the second index (column).
47static const BYTE aes_sbox[16][16] = {
48 {0x63,0x7C,0x77,0x7B,0xF2,0x6B,0x6F,0xC5,0x30,0x01,0x67,0x2B,0xFE,0xD7,0xAB,0x76},
49 {0xCA,0x82,0xC9,0x7D,0xFA,0x59,0x47,0xF0,0xAD,0xD4,0xA2,0xAF,0x9C,0xA4,0x72,0xC0},
50 {0xB7,0xFD,0x93,0x26,0x36,0x3F,0xF7,0xCC,0x34,0xA5,0xE5,0xF1,0x71,0xD8,0x31,0x15},
51 {0x04,0xC7,0x23,0xC3,0x18,0x96,0x05,0x9A,0x07,0x12,0x80,0xE2,0xEB,0x27,0xB2,0x75},
52 {0x09,0x83,0x2C,0x1A,0x1B,0x6E,0x5A,0xA0,0x52,0x3B,0xD6,0xB3,0x29,0xE3,0x2F,0x84},
53 {0x53,0xD1,0x00,0xED,0x20,0xFC,0xB1,0x5B,0x6A,0xCB,0xBE,0x39,0x4A,0x4C,0x58,0xCF},
54 {0xD0,0xEF,0xAA,0xFB,0x43,0x4D,0x33,0x85,0x45,0xF9,0x02,0x7F,0x50,0x3C,0x9F,0xA8},
55 {0x51,0xA3,0x40,0x8F,0x92,0x9D,0x38,0xF5,0xBC,0xB6,0xDA,0x21,0x10,0xFF,0xF3,0xD2},
56 {0xCD,0x0C,0x13,0xEC,0x5F,0x97,0x44,0x17,0xC4,0xA7,0x7E,0x3D,0x64,0x5D,0x19,0x73},
57 {0x60,0x81,0x4F,0xDC,0x22,0x2A,0x90,0x88,0x46,0xEE,0xB8,0x14,0xDE,0x5E,0x0B,0xDB},
58 {0xE0,0x32,0x3A,0x0A,0x49,0x06,0x24,0x5C,0xC2,0xD3,0xAC,0x62,0x91,0x95,0xE4,0x79},
59 {0xE7,0xC8,0x37,0x6D,0x8D,0xD5,0x4E,0xA9,0x6C,0x56,0xF4,0xEA,0x65,0x7A,0xAE,0x08},
60 {0xBA,0x78,0x25,0x2E,0x1C,0xA6,0xB4,0xC6,0xE8,0xDD,0x74,0x1F,0x4B,0xBD,0x8B,0x8A},
61 {0x70,0x3E,0xB5,0x66,0x48,0x03,0xF6,0x0E,0x61,0x35,0x57,0xB9,0x86,0xC1,0x1D,0x9E},
62 {0xE1,0xF8,0x98,0x11,0x69,0xD9,0x8E,0x94,0x9B,0x1E,0x87,0xE9,0xCE,0x55,0x28,0xDF},
63 {0x8C,0xA1,0x89,0x0D,0xBF,0xE6,0x42,0x68,0x41,0x99,0x2D,0x0F,0xB0,0x54,0xBB,0x16}
64};
65
66static const BYTE aes_invsbox[16][16] = {
67 {0x52,0x09,0x6A,0xD5,0x30,0x36,0xA5,0x38,0xBF,0x40,0xA3,0x9E,0x81,0xF3,0xD7,0xFB},
68 {0x7C,0xE3,0x39,0x82,0x9B,0x2F,0xFF,0x87,0x34,0x8E,0x43,0x44,0xC4,0xDE,0xE9,0xCB},
69 {0x54,0x7B,0x94,0x32,0xA6,0xC2,0x23,0x3D,0xEE,0x4C,0x95,0x0B,0x42,0xFA,0xC3,0x4E},
70 {0x08,0x2E,0xA1,0x66,0x28,0xD9,0x24,0xB2,0x76,0x5B,0xA2,0x49,0x6D,0x8B,0xD1,0x25},
71 {0x72,0xF8,0xF6,0x64,0x86,0x68,0x98,0x16,0xD4,0xA4,0x5C,0xCC,0x5D,0x65,0xB6,0x92},
72 {0x6C,0x70,0x48,0x50,0xFD,0xED,0xB9,0xDA,0x5E,0x15,0x46,0x57,0xA7,0x8D,0x9D,0x84},
73 {0x90,0xD8,0xAB,0x00,0x8C,0xBC,0xD3,0x0A,0xF7,0xE4,0x58,0x05,0xB8,0xB3,0x45,0x06},
74 {0xD0,0x2C,0x1E,0x8F,0xCA,0x3F,0x0F,0x02,0xC1,0xAF,0xBD,0x03,0x01,0x13,0x8A,0x6B},
75 {0x3A,0x91,0x11,0x41,0x4F,0x67,0xDC,0xEA,0x97,0xF2,0xCF,0xCE,0xF0,0xB4,0xE6,0x73},
76 {0x96,0xAC,0x74,0x22,0xE7,0xAD,0x35,0x85,0xE2,0xF9,0x37,0xE8,0x1C,0x75,0xDF,0x6E},
77 {0x47,0xF1,0x1A,0x71,0x1D,0x29,0xC5,0x89,0x6F,0xB7,0x62,0x0E,0xAA,0x18,0xBE,0x1B},
78 {0xFC,0x56,0x3E,0x4B,0xC6,0xD2,0x79,0x20,0x9A,0xDB,0xC0,0xFE,0x78,0xCD,0x5A,0xF4},
79 {0x1F,0xDD,0xA8,0x33,0x88,0x07,0xC7,0x31,0xB1,0x12,0x10,0x59,0x27,0x80,0xEC,0x5F},
80 {0x60,0x51,0x7F,0xA9,0x19,0xB5,0x4A,0x0D,0x2D,0xE5,0x7A,0x9F,0x93,0xC9,0x9C,0xEF},
81 {0xA0,0xE0,0x3B,0x4D,0xAE,0x2A,0xF5,0xB0,0xC8,0xEB,0xBB,0x3C,0x83,0x53,0x99,0x61},
82 {0x17,0x2B,0x04,0x7E,0xBA,0x77,0xD6,0x26,0xE1,0x69,0x14,0x63,0x55,0x21,0x0C,0x7D}
83};
84
85// This table stores pre-calculated values for all possible GF(2^8) calculations.This
86// table is only used by the (Inv)MixColumns steps.
87// USAGE: The second index (column) is the coefficient of multiplication. Only 7 different
88// coefficients are used: 0x01, 0x02, 0x03, 0x09, 0x0b, 0x0d, 0x0e, but multiplication by
89// 1 is negligible leaving only 6 coefficients. Each column of the table is devoted to one
90// of these coefficients, in the ascending order of value, from values 0x00 to 0xFF.
91static const BYTE gf_mul[256][6] = {
92 {0x00,0x00,0x00,0x00,0x00,0x00},{0x02,0x03,0x09,0x0b,0x0d,0x0e},
93 {0x04,0x06,0x12,0x16,0x1a,0x1c},{0x06,0x05,0x1b,0x1d,0x17,0x12},
94 {0x08,0x0c,0x24,0x2c,0x34,0x38},{0x0a,0x0f,0x2d,0x27,0x39,0x36},
95 {0x0c,0x0a,0x36,0x3a,0x2e,0x24},{0x0e,0x09,0x3f,0x31,0x23,0x2a},
96 {0x10,0x18,0x48,0x58,0x68,0x70},{0x12,0x1b,0x41,0x53,0x65,0x7e},
97 {0x14,0x1e,0x5a,0x4e,0x72,0x6c},{0x16,0x1d,0x53,0x45,0x7f,0x62},
98 {0x18,0x14,0x6c,0x74,0x5c,0x48},{0x1a,0x17,0x65,0x7f,0x51,0x46},
99 {0x1c,0x12,0x7e,0x62,0x46,0x54},{0x1e,0x11,0x77,0x69,0x4b,0x5a},
100 {0x20,0x30,0x90,0xb0,0xd0,0xe0},{0x22,0x33,0x99,0xbb,0xdd,0xee},
101 {0x24,0x36,0x82,0xa6,0xca,0xfc},{0x26,0x35,0x8b,0xad,0xc7,0xf2},
102 {0x28,0x3c,0xb4,0x9c,0xe4,0xd8},{0x2a,0x3f,0xbd,0x97,0xe9,0xd6},
103 {0x2c,0x3a,0xa6,0x8a,0xfe,0xc4},{0x2e,0x39,0xaf,0x81,0xf3,0xca},
104 {0x30,0x28,0xd8,0xe8,0xb8,0x90},{0x32,0x2b,0xd1,0xe3,0xb5,0x9e},
105 {0x34,0x2e,0xca,0xfe,0xa2,0x8c},{0x36,0x2d,0xc3,0xf5,0xaf,0x82},
106 {0x38,0x24,0xfc,0xc4,0x8c,0xa8},{0x3a,0x27,0xf5,0xcf,0x81,0xa6},
107 {0x3c,0x22,0xee,0xd2,0x96,0xb4},{0x3e,0x21,0xe7,0xd9,0x9b,0xba},
108 {0x40,0x60,0x3b,0x7b,0xbb,0xdb},{0x42,0x63,0x32,0x70,0xb6,0xd5},
109 {0x44,0x66,0x29,0x6d,0xa1,0xc7},{0x46,0x65,0x20,0x66,0xac,0xc9},
110 {0x48,0x6c,0x1f,0x57,0x8f,0xe3},{0x4a,0x6f,0x16,0x5c,0x82,0xed},
111 {0x4c,0x6a,0x0d,0x41,0x95,0xff},{0x4e,0x69,0x04,0x4a,0x98,0xf1},
112 {0x50,0x78,0x73,0x23,0xd3,0xab},{0x52,0x7b,0x7a,0x28,0xde,0xa5},
113 {0x54,0x7e,0x61,0x35,0xc9,0xb7},{0x56,0x7d,0x68,0x3e,0xc4,0xb9},
114 {0x58,0x74,0x57,0x0f,0xe7,0x93},{0x5a,0x77,0x5e,0x04,0xea,0x9d},
115 {0x5c,0x72,0x45,0x19,0xfd,0x8f},{0x5e,0x71,0x4c,0x12,0xf0,0x81},
116 {0x60,0x50,0xab,0xcb,0x6b,0x3b},{0x62,0x53,0xa2,0xc0,0x66,0x35},
117 {0x64,0x56,0xb9,0xdd,0x71,0x27},{0x66,0x55,0xb0,0xd6,0x7c,0x29},
118 {0x68,0x5c,0x8f,0xe7,0x5f,0x03},{0x6a,0x5f,0x86,0xec,0x52,0x0d},
119 {0x6c,0x5a,0x9d,0xf1,0x45,0x1f},{0x6e,0x59,0x94,0xfa,0x48,0x11},
120 {0x70,0x48,0xe3,0x93,0x03,0x4b},{0x72,0x4b,0xea,0x98,0x0e,0x45},
121 {0x74,0x4e,0xf1,0x85,0x19,0x57},{0x76,0x4d,0xf8,0x8e,0x14,0x59},
122 {0x78,0x44,0xc7,0xbf,0x37,0x73},{0x7a,0x47,0xce,0xb4,0x3a,0x7d},
123 {0x7c,0x42,0xd5,0xa9,0x2d,0x6f},{0x7e,0x41,0xdc,0xa2,0x20,0x61},
124 {0x80,0xc0,0x76,0xf6,0x6d,0xad},{0x82,0xc3,0x7f,0xfd,0x60,0xa3},
125 {0x84,0xc6,0x64,0xe0,0x77,0xb1},{0x86,0xc5,0x6d,0xeb,0x7a,0xbf},
126 {0x88,0xcc,0x52,0xda,0x59,0x95},{0x8a,0xcf,0x5b,0xd1,0x54,0x9b},
127 {0x8c,0xca,0x40,0xcc,0x43,0x89},{0x8e,0xc9,0x49,0xc7,0x4e,0x87},
128 {0x90,0xd8,0x3e,0xae,0x05,0xdd},{0x92,0xdb,0x37,0xa5,0x08,0xd3},
129 {0x94,0xde,0x2c,0xb8,0x1f,0xc1},{0x96,0xdd,0x25,0xb3,0x12,0xcf},
130 {0x98,0xd4,0x1a,0x82,0x31,0xe5},{0x9a,0xd7,0x13,0x89,0x3c,0xeb},
131 {0x9c,0xd2,0x08,0x94,0x2b,0xf9},{0x9e,0xd1,0x01,0x9f,0x26,0xf7},
132 {0xa0,0xf0,0xe6,0x46,0xbd,0x4d},{0xa2,0xf3,0xef,0x4d,0xb0,0x43},
133 {0xa4,0xf6,0xf4,0x50,0xa7,0x51},{0xa6,0xf5,0xfd,0x5b,0xaa,0x5f},
134 {0xa8,0xfc,0xc2,0x6a,0x89,0x75},{0xaa,0xff,0xcb,0x61,0x84,0x7b},
135 {0xac,0xfa,0xd0,0x7c,0x93,0x69},{0xae,0xf9,0xd9,0x77,0x9e,0x67},
136 {0xb0,0xe8,0xae,0x1e,0xd5,0x3d},{0xb2,0xeb,0xa7,0x15,0xd8,0x33},
137 {0xb4,0xee,0xbc,0x08,0xcf,0x21},{0xb6,0xed,0xb5,0x03,0xc2,0x2f},
138 {0xb8,0xe4,0x8a,0x32,0xe1,0x05},{0xba,0xe7,0x83,0x39,0xec,0x0b},
139 {0xbc,0xe2,0x98,0x24,0xfb,0x19},{0xbe,0xe1,0x91,0x2f,0xf6,0x17},
140 {0xc0,0xa0,0x4d,0x8d,0xd6,0x76},{0xc2,0xa3,0x44,0x86,0xdb,0x78},
141 {0xc4,0xa6,0x5f,0x9b,0xcc,0x6a},{0xc6,0xa5,0x56,0x90,0xc1,0x64},
142 {0xc8,0xac,0x69,0xa1,0xe2,0x4e},{0xca,0xaf,0x60,0xaa,0xef,0x40},
143 {0xcc,0xaa,0x7b,0xb7,0xf8,0x52},{0xce,0xa9,0x72,0xbc,0xf5,0x5c},
144 {0xd0,0xb8,0x05,0xd5,0xbe,0x06},{0xd2,0xbb,0x0c,0xde,0xb3,0x08},
145 {0xd4,0xbe,0x17,0xc3,0xa4,0x1a},{0xd6,0xbd,0x1e,0xc8,0xa9,0x14},
146 {0xd8,0xb4,0x21,0xf9,0x8a,0x3e},{0xda,0xb7,0x28,0xf2,0x87,0x30},
147 {0xdc,0xb2,0x33,0xef,0x90,0x22},{0xde,0xb1,0x3a,0xe4,0x9d,0x2c},
148 {0xe0,0x90,0xdd,0x3d,0x06,0x96},{0xe2,0x93,0xd4,0x36,0x0b,0x98},
149 {0xe4,0x96,0xcf,0x2b,0x1c,0x8a},{0xe6,0x95,0xc6,0x20,0x11,0x84},
150 {0xe8,0x9c,0xf9,0x11,0x32,0xae},{0xea,0x9f,0xf0,0x1a,0x3f,0xa0},
151 {0xec,0x9a,0xeb,0x07,0x28,0xb2},{0xee,0x99,0xe2,0x0c,0x25,0xbc},
152 {0xf0,0x88,0x95,0x65,0x6e,0xe6},{0xf2,0x8b,0x9c,0x6e,0x63,0xe8},
153 {0xf4,0x8e,0x87,0x73,0x74,0xfa},{0xf6,0x8d,0x8e,0x78,0x79,0xf4},
154 {0xf8,0x84,0xb1,0x49,0x5a,0xde},{0xfa,0x87,0xb8,0x42,0x57,0xd0},
155 {0xfc,0x82,0xa3,0x5f,0x40,0xc2},{0xfe,0x81,0xaa,0x54,0x4d,0xcc},
156 {0x1b,0x9b,0xec,0xf7,0xda,0x41},{0x19,0x98,0xe5,0xfc,0xd7,0x4f},
157 {0x1f,0x9d,0xfe,0xe1,0xc0,0x5d},{0x1d,0x9e,0xf7,0xea,0xcd,0x53},
158 {0x13,0x97,0xc8,0xdb,0xee,0x79},{0x11,0x94,0xc1,0xd0,0xe3,0x77},
159 {0x17,0x91,0xda,0xcd,0xf4,0x65},{0x15,0x92,0xd3,0xc6,0xf9,0x6b},
160 {0x0b,0x83,0xa4,0xaf,0xb2,0x31},{0x09,0x80,0xad,0xa4,0xbf,0x3f},
161 {0x0f,0x85,0xb6,0xb9,0xa8,0x2d},{0x0d,0x86,0xbf,0xb2,0xa5,0x23},
162 {0x03,0x8f,0x80,0x83,0x86,0x09},{0x01,0x8c,0x89,0x88,0x8b,0x07},
163 {0x07,0x89,0x92,0x95,0x9c,0x15},{0x05,0x8a,0x9b,0x9e,0x91,0x1b},
164 {0x3b,0xab,0x7c,0x47,0x0a,0xa1},{0x39,0xa8,0x75,0x4c,0x07,0xaf},
165 {0x3f,0xad,0x6e,0x51,0x10,0xbd},{0x3d,0xae,0x67,0x5a,0x1d,0xb3},
166 {0x33,0xa7,0x58,0x6b,0x3e,0x99},{0x31,0xa4,0x51,0x60,0x33,0x97},
167 {0x37,0xa1,0x4a,0x7d,0x24,0x85},{0x35,0xa2,0x43,0x76,0x29,0x8b},
168 {0x2b,0xb3,0x34,0x1f,0x62,0xd1},{0x29,0xb0,0x3d,0x14,0x6f,0xdf},
169 {0x2f,0xb5,0x26,0x09,0x78,0xcd},{0x2d,0xb6,0x2f,0x02,0x75,0xc3},
170 {0x23,0xbf,0x10,0x33,0x56,0xe9},{0x21,0xbc,0x19,0x38,0x5b,0xe7},
171 {0x27,0xb9,0x02,0x25,0x4c,0xf5},{0x25,0xba,0x0b,0x2e,0x41,0xfb},
172 {0x5b,0xfb,0xd7,0x8c,0x61,0x9a},{0x59,0xf8,0xde,0x87,0x6c,0x94},
173 {0x5f,0xfd,0xc5,0x9a,0x7b,0x86},{0x5d,0xfe,0xcc,0x91,0x76,0x88},
174 {0x53,0xf7,0xf3,0xa0,0x55,0xa2},{0x51,0xf4,0xfa,0xab,0x58,0xac},
175 {0x57,0xf1,0xe1,0xb6,0x4f,0xbe},{0x55,0xf2,0xe8,0xbd,0x42,0xb0},
176 {0x4b,0xe3,0x9f,0xd4,0x09,0xea},{0x49,0xe0,0x96,0xdf,0x04,0xe4},
177 {0x4f,0xe5,0x8d,0xc2,0x13,0xf6},{0x4d,0xe6,0x84,0xc9,0x1e,0xf8},
178 {0x43,0xef,0xbb,0xf8,0x3d,0xd2},{0x41,0xec,0xb2,0xf3,0x30,0xdc},
179 {0x47,0xe9,0xa9,0xee,0x27,0xce},{0x45,0xea,0xa0,0xe5,0x2a,0xc0},
180 {0x7b,0xcb,0x47,0x3c,0xb1,0x7a},{0x79,0xc8,0x4e,0x37,0xbc,0x74},
181 {0x7f,0xcd,0x55,0x2a,0xab,0x66},{0x7d,0xce,0x5c,0x21,0xa6,0x68},
182 {0x73,0xc7,0x63,0x10,0x85,0x42},{0x71,0xc4,0x6a,0x1b,0x88,0x4c},
183 {0x77,0xc1,0x71,0x06,0x9f,0x5e},{0x75,0xc2,0x78,0x0d,0x92,0x50},
184 {0x6b,0xd3,0x0f,0x64,0xd9,0x0a},{0x69,0xd0,0x06,0x6f,0xd4,0x04},
185 {0x6f,0xd5,0x1d,0x72,0xc3,0x16},{0x6d,0xd6,0x14,0x79,0xce,0x18},
186 {0x63,0xdf,0x2b,0x48,0xed,0x32},{0x61,0xdc,0x22,0x43,0xe0,0x3c},
187 {0x67,0xd9,0x39,0x5e,0xf7,0x2e},{0x65,0xda,0x30,0x55,0xfa,0x20},
188 {0x9b,0x5b,0x9a,0x01,0xb7,0xec},{0x99,0x58,0x93,0x0a,0xba,0xe2},
189 {0x9f,0x5d,0x88,0x17,0xad,0xf0},{0x9d,0x5e,0x81,0x1c,0xa0,0xfe},
190 {0x93,0x57,0xbe,0x2d,0x83,0xd4},{0x91,0x54,0xb7,0x26,0x8e,0xda},
191 {0x97,0x51,0xac,0x3b,0x99,0xc8},{0x95,0x52,0xa5,0x30,0x94,0xc6},
192 {0x8b,0x43,0xd2,0x59,0xdf,0x9c},{0x89,0x40,0xdb,0x52,0xd2,0x92},
193 {0x8f,0x45,0xc0,0x4f,0xc5,0x80},{0x8d,0x46,0xc9,0x44,0xc8,0x8e},
194 {0x83,0x4f,0xf6,0x75,0xeb,0xa4},{0x81,0x4c,0xff,0x7e,0xe6,0xaa},
195 {0x87,0x49,0xe4,0x63,0xf1,0xb8},{0x85,0x4a,0xed,0x68,0xfc,0xb6},
196 {0xbb,0x6b,0x0a,0xb1,0x67,0x0c},{0xb9,0x68,0x03,0xba,0x6a,0x02},
197 {0xbf,0x6d,0x18,0xa7,0x7d,0x10},{0xbd,0x6e,0x11,0xac,0x70,0x1e},
198 {0xb3,0x67,0x2e,0x9d,0x53,0x34},{0xb1,0x64,0x27,0x96,0x5e,0x3a},
199 {0xb7,0x61,0x3c,0x8b,0x49,0x28},{0xb5,0x62,0x35,0x80,0x44,0x26},
200 {0xab,0x73,0x42,0xe9,0x0f,0x7c},{0xa9,0x70,0x4b,0xe2,0x02,0x72},
201 {0xaf,0x75,0x50,0xff,0x15,0x60},{0xad,0x76,0x59,0xf4,0x18,0x6e},
202 {0xa3,0x7f,0x66,0xc5,0x3b,0x44},{0xa1,0x7c,0x6f,0xce,0x36,0x4a},
203 {0xa7,0x79,0x74,0xd3,0x21,0x58},{0xa5,0x7a,0x7d,0xd8,0x2c,0x56},
204 {0xdb,0x3b,0xa1,0x7a,0x0c,0x37},{0xd9,0x38,0xa8,0x71,0x01,0x39},
205 {0xdf,0x3d,0xb3,0x6c,0x16,0x2b},{0xdd,0x3e,0xba,0x67,0x1b,0x25},
206 {0xd3,0x37,0x85,0x56,0x38,0x0f},{0xd1,0x34,0x8c,0x5d,0x35,0x01},
207 {0xd7,0x31,0x97,0x40,0x22,0x13},{0xd5,0x32,0x9e,0x4b,0x2f,0x1d},
208 {0xcb,0x23,0xe9,0x22,0x64,0x47},{0xc9,0x20,0xe0,0x29,0x69,0x49},
209 {0xcf,0x25,0xfb,0x34,0x7e,0x5b},{0xcd,0x26,0xf2,0x3f,0x73,0x55},
210 {0xc3,0x2f,0xcd,0x0e,0x50,0x7f},{0xc1,0x2c,0xc4,0x05,0x5d,0x71},
211 {0xc7,0x29,0xdf,0x18,0x4a,0x63},{0xc5,0x2a,0xd6,0x13,0x47,0x6d},
212 {0xfb,0x0b,0x31,0xca,0xdc,0xd7},{0xf9,0x08,0x38,0xc1,0xd1,0xd9},
213 {0xff,0x0d,0x23,0xdc,0xc6,0xcb},{0xfd,0x0e,0x2a,0xd7,0xcb,0xc5},
214 {0xf3,0x07,0x15,0xe6,0xe8,0xef},{0xf1,0x04,0x1c,0xed,0xe5,0xe1},
215 {0xf7,0x01,0x07,0xf0,0xf2,0xf3},{0xf5,0x02,0x0e,0xfb,0xff,0xfd},
216 {0xeb,0x13,0x79,0x92,0xb4,0xa7},{0xe9,0x10,0x70,0x99,0xb9,0xa9},
217 {0xef,0x15,0x6b,0x84,0xae,0xbb},{0xed,0x16,0x62,0x8f,0xa3,0xb5},
218 {0xe3,0x1f,0x5d,0xbe,0x80,0x9f},{0xe1,0x1c,0x54,0xb5,0x8d,0x91},
219 {0xe7,0x19,0x4f,0xa8,0x9a,0x83},{0xe5,0x1a,0x46,0xa3,0x97,0x8d}
220};
221
222/*********************** FUNCTION DEFINITIONS ***********************/
223// XORs the in and out buffers, storing the result in out. Length is in bytes.
224void xor_buf(const BYTE in[], BYTE out[], size_t len)
225{
226 size_t idx;
227
228 for (idx = 0; idx < len; idx++)
229 out[idx] ^= in[idx];
230}
231
232/*******************
233* AES - CBC
234*******************/
235int aes_encrypt_cbc(const BYTE in[], size_t in_len, BYTE out[], const WORD key[], int keysize, const BYTE iv[])
236{
237 BYTE buf_in[AES_BLOCK_SIZE], buf_out[AES_BLOCK_SIZE];
238 int blocks, idx;
239
240 if (in_len % AES_BLOCK_SIZE != 0)
241 return(FALSE);
242
243 blocks = in_len / AES_BLOCK_SIZE;
244
245 memcpy(dest: buf_out, src: iv, AES_BLOCK_SIZE);
246
247 for (idx = 0; idx < blocks; idx++) {
248 memcpy(dest: buf_in, src: &in[idx * AES_BLOCK_SIZE], AES_BLOCK_SIZE);
249 xor_buf(in: buf_out, out: buf_in, AES_BLOCK_SIZE);
250 aes_encrypt(in: buf_in, out: buf_out, key, keysize);
251 memcpy(dest: &out[idx * AES_BLOCK_SIZE], src: buf_out, AES_BLOCK_SIZE);
252 }
253
254 return(TRUE);
255}
256
257int aes_encrypt_cbc_mac(const BYTE in[], size_t in_len, BYTE out[], const WORD key[], int keysize, const BYTE iv[])
258{
259 BYTE buf_in[AES_BLOCK_SIZE], buf_out[AES_BLOCK_SIZE];
260 int blocks, idx;
261
262 if (in_len % AES_BLOCK_SIZE != 0)
263 return(FALSE);
264
265 blocks = in_len / AES_BLOCK_SIZE;
266
267 memcpy(dest: buf_out, src: iv, AES_BLOCK_SIZE);
268
269 for (idx = 0; idx < blocks; idx++) {
270 memcpy(dest: buf_in, src: &in[idx * AES_BLOCK_SIZE], AES_BLOCK_SIZE);
271 xor_buf(in: buf_out, out: buf_in, AES_BLOCK_SIZE);
272 aes_encrypt(in: buf_in, out: buf_out, key, keysize);
273 // Do not output all encrypted blocks.
274 }
275
276 memcpy(dest: out, src: buf_out, AES_BLOCK_SIZE); // Only output the last block.
277
278 return(TRUE);
279}
280
281// No need for an aes_decrypt_cbc() for just CCM.
282
283/*******************
284* AES - CTR
285*******************/
286void increment_iv(BYTE iv[], int counter_size)
287{
288 int idx;
289
290 // Use counter_size bytes at the end of the IV as the big-endian integer to increment.
291 for (idx = AES_BLOCK_SIZE - 1; idx >= AES_BLOCK_SIZE - counter_size; idx--) {
292 iv[idx]++;
293 if (iv[idx] != 0 || idx == AES_BLOCK_SIZE - counter_size)
294 break;
295 }
296}
297
298// Performs the encryption in-place, the input and output buffers may be the same.
299// Input may be an arbitrary length (in bytes).
300void aes_encrypt_ctr(const BYTE in[], size_t in_len, BYTE out[], const WORD key[], int keysize, const BYTE iv[])
301{
302 size_t idx = 0, last_block_length;
303 BYTE iv_buf[AES_BLOCK_SIZE], out_buf[AES_BLOCK_SIZE];
304
305 if (in != out)
306 memcpy(dest: out, src: in, n: in_len);
307
308 memcpy(dest: iv_buf, src: iv, AES_BLOCK_SIZE);
309 last_block_length = in_len - AES_BLOCK_SIZE;
310
311 if (in_len > AES_BLOCK_SIZE) {
312 for (idx = 0; idx < last_block_length; idx += AES_BLOCK_SIZE) {
313 aes_encrypt(in: iv_buf, out: out_buf, key, keysize);
314 xor_buf(in: out_buf, out: &out[idx], AES_BLOCK_SIZE);
315 increment_iv(iv: iv_buf, AES_BLOCK_SIZE);
316 }
317 }
318
319 aes_encrypt(in: iv_buf, out: out_buf, key, keysize);
320 xor_buf(in: out_buf, out: &out[idx], len: in_len - idx); // Use the Most Significant bytes.
321}
322
323void aes_decrypt_ctr(const BYTE in[], size_t in_len, BYTE out[], const WORD key[], int keysize, const BYTE iv[])
324{
325 // CTR encryption is its own inverse function.
326 aes_encrypt_ctr(in, in_len, out, key, keysize, iv);
327}
328
329/*******************
330* AES - CCM
331*******************/
332// out_len = payload_len + assoc_len
333int aes_encrypt_ccm(const BYTE payload[], WORD payload_len, const BYTE assoc[], unsigned short assoc_len,
334 const BYTE nonce[], unsigned short nonce_len, BYTE out[], WORD *out_len,
335 WORD mac_len, const BYTE key_str[], int keysize)
336{
337 BYTE temp_iv[AES_BLOCK_SIZE], counter[AES_BLOCK_SIZE], mac[16], *buf;
338 int end_of_buf, payload_len_store_size;
339 WORD key[60];
340
341 if (mac_len != 4 && mac_len != 6 && mac_len != 8 && mac_len != 10 &&
342 mac_len != 12 && mac_len != 14 && mac_len != 16)
343 return(FALSE);
344
345 if (nonce_len < 7 || nonce_len > 13)
346 return(FALSE);
347
348 if (assoc_len > 32768 /* = 2^15 */)
349 return(FALSE);
350
351 buf = (BYTE*)malloc(size: payload_len + assoc_len + 48 /*Round both payload and associated data up a block size and add an extra block.*/);
352 if (! buf)
353 return(FALSE);
354
355 // Prepare the key for usage.
356 aes_key_setup(key: key_str, w: key, keysize);
357
358 // Format the first block of the formatted data.
359 payload_len_store_size = AES_BLOCK_SIZE - 1 - nonce_len;
360 ccm_prepare_first_format_blk(buf, assoc_len, payload_len, payload_len_store_size, mac_len, nonce, nonce_len);
361 end_of_buf = AES_BLOCK_SIZE;
362
363 // Format the Associated Data, aka, assoc[].
364 ccm_format_assoc_data(buf, end_of_buf: &end_of_buf, assoc, assoc_len);
365
366 // Format the Payload, aka payload[].
367 ccm_format_payload_data(buf, end_of_buf: &end_of_buf, payload, payload_len);
368
369 // Create the first counter block.
370 ccm_prepare_first_ctr_blk(counter, nonce, nonce_len, payload_len_store_size);
371
372 // Perform the CBC operation with an IV of zeros on the formatted buffer to calculate the MAC.
373 memset(s: temp_iv, c: 0, AES_BLOCK_SIZE);
374 aes_encrypt_cbc_mac(in: buf, in_len: end_of_buf, out: mac, key, keysize, iv: temp_iv);
375
376 // Copy the Payload and MAC to the output buffer.
377 memcpy(dest: out, src: payload, n: payload_len);
378 memcpy(dest: &out[payload_len], src: mac, n: mac_len);
379
380 // Encrypt the Payload with CTR mode with a counter starting at 1.
381 memcpy(dest: temp_iv, src: counter, AES_BLOCK_SIZE);
382 increment_iv(iv: temp_iv, AES_BLOCK_SIZE - 1 - mac_len); // Last argument is the byte size of the counting portion of the counter block. /*BUG?*/
383 aes_encrypt_ctr(in: out, in_len: payload_len, out, key, keysize, iv: temp_iv);
384
385 // Encrypt the MAC with CTR mode with a counter starting at 0.
386 aes_encrypt_ctr(in: &out[payload_len], in_len: mac_len, out: &out[payload_len], key, keysize, iv: counter);
387
388 free(ptr: buf);
389 *out_len = payload_len + mac_len;
390
391 return(TRUE);
392}
393
394// plaintext_len = ciphertext_len - mac_len
395// Needs a flag for whether the MAC matches.
396int aes_decrypt_ccm(const BYTE ciphertext[], WORD ciphertext_len, const BYTE assoc[], unsigned short assoc_len,
397 const BYTE nonce[], unsigned short nonce_len, BYTE plaintext[], WORD *plaintext_len,
398 WORD mac_len, int *mac_auth, const BYTE key_str[], int keysize)
399{
400 BYTE temp_iv[AES_BLOCK_SIZE], counter[AES_BLOCK_SIZE], mac[16], mac_buf[16], *buf;
401 int end_of_buf, plaintext_len_store_size;
402 WORD key[60];
403
404 if (ciphertext_len <= mac_len)
405 return(FALSE);
406
407 buf = (BYTE*)malloc(size: assoc_len + ciphertext_len /*ciphertext_len = plaintext_len + mac_len*/ + 48);
408 if (! buf)
409 return(FALSE);
410
411 // Prepare the key for usage.
412 aes_key_setup(key: key_str, w: key, keysize);
413
414 // Copy the plaintext and MAC to the output buffers.
415 *plaintext_len = ciphertext_len - mac_len;
416 plaintext_len_store_size = AES_BLOCK_SIZE - 1 - nonce_len;
417 memcpy(dest: plaintext, src: ciphertext, n: *plaintext_len);
418 memcpy(dest: mac, src: &ciphertext[*plaintext_len], n: mac_len);
419
420 // Prepare the first counter block for use in decryption.
421 ccm_prepare_first_ctr_blk(counter, nonce, nonce_len, payload_len_store_size: plaintext_len_store_size);
422
423 // Decrypt the Payload with CTR mode with a counter starting at 1.
424 memcpy(dest: temp_iv, src: counter, AES_BLOCK_SIZE);
425 increment_iv(iv: temp_iv, AES_BLOCK_SIZE - 1 - mac_len); // (AES_BLOCK_SIZE - 1 - mac_len) is the byte size of the counting portion of the counter block.
426 aes_decrypt_ctr(in: plaintext, in_len: *plaintext_len, out: plaintext, key, keysize, iv: temp_iv);
427
428 // Setting mac_auth to NULL disables the authentication check.
429 if (mac_auth != NULL) {
430 // Decrypt the MAC with CTR mode with a counter starting at 0.
431 aes_decrypt_ctr(in: mac, in_len: mac_len, out: mac, key, keysize, iv: counter);
432
433 // Format the first block of the formatted data.
434 plaintext_len_store_size = AES_BLOCK_SIZE - 1 - nonce_len;
435 ccm_prepare_first_format_blk(buf, assoc_len, payload_len: *plaintext_len, payload_len_store_size: plaintext_len_store_size, mac_len, nonce, nonce_len);
436 end_of_buf = AES_BLOCK_SIZE;
437
438 // Format the Associated Data into the authentication buffer.
439 ccm_format_assoc_data(buf, end_of_buf: &end_of_buf, assoc, assoc_len);
440
441 // Format the Payload into the authentication buffer.
442 ccm_format_payload_data(buf, end_of_buf: &end_of_buf, payload: plaintext, payload_len: *plaintext_len);
443
444 // Perform the CBC operation with an IV of zeros on the formatted buffer to calculate the MAC.
445 memset(s: temp_iv, c: 0, AES_BLOCK_SIZE);
446 aes_encrypt_cbc_mac(in: buf, in_len: end_of_buf, out: mac_buf, key, keysize, iv: temp_iv);
447
448 // Compare the calculated MAC against the MAC embedded in the ciphertext to see if they are the same.
449 if (! memcmp(s1: mac, s2: mac_buf, n: mac_len)) {
450 *mac_auth = TRUE;
451 }
452 else {
453 *mac_auth = FALSE;
454 memset(s: plaintext, c: 0, n: *plaintext_len);
455 }
456 }
457
458 free(ptr: buf);
459
460 return(TRUE);
461}
462
463// Creates the first counter block. First byte is flags, then the nonce, then the incremented part.
464void ccm_prepare_first_ctr_blk(BYTE counter[], const BYTE nonce[], int nonce_len, int payload_len_store_size)
465{
466 memset(s: counter, c: 0, AES_BLOCK_SIZE);
467 counter[0] = (payload_len_store_size - 1) & 0x07;
468 memcpy(dest: &counter[1], src: nonce, n: nonce_len);
469}
470
471void ccm_prepare_first_format_blk(BYTE buf[], int assoc_len, int payload_len, int payload_len_store_size, int mac_len, const BYTE nonce[], int nonce_len)
472{
473 // Set the flags for the first byte of the first block.
474 buf[0] = ((((mac_len - 2) / 2) & 0x07) << 3) | ((payload_len_store_size - 1) & 0x07);
475 if (assoc_len > 0)
476 buf[0] += 0x40;
477 // Format the rest of the first block, storing the nonce and the size of the payload.
478 memcpy(dest: &buf[1], src: nonce, n: nonce_len);
479 memset(s: &buf[1 + nonce_len], c: 0, AES_BLOCK_SIZE - 1 - nonce_len);
480 buf[15] = payload_len & 0x000000FF;
481 buf[14] = (payload_len >> 8) & 0x000000FF;
482}
483
484void ccm_format_assoc_data(BYTE buf[], int *end_of_buf, const BYTE assoc[], int assoc_len)
485{
486 int pad;
487
488 buf[*end_of_buf + 1] = assoc_len & 0x00FF;
489 buf[*end_of_buf] = (assoc_len >> 8) & 0x00FF;
490 *end_of_buf += 2;
491 memcpy(dest: &buf[*end_of_buf], src: assoc, n: assoc_len);
492 *end_of_buf += assoc_len;
493 pad = AES_BLOCK_SIZE - (*end_of_buf % AES_BLOCK_SIZE); /*BUG?*/
494 memset(s: &buf[*end_of_buf], c: 0, n: pad);
495 *end_of_buf += pad;
496}
497
498void ccm_format_payload_data(BYTE buf[], int *end_of_buf, const BYTE payload[], int payload_len)
499{
500 int pad;
501
502 memcpy(dest: &buf[*end_of_buf], src: payload, n: payload_len);
503 *end_of_buf += payload_len;
504 pad = *end_of_buf % AES_BLOCK_SIZE;
505 if (pad != 0)
506 pad = AES_BLOCK_SIZE - pad;
507 memset(s: &buf[*end_of_buf], c: 0, n: pad);
508 *end_of_buf += pad;
509}
510
511/*******************
512* AES
513*******************/
514/////////////////
515// KEY EXPANSION
516/////////////////
517
518// Substitutes a word using the AES S-Box.
519WORD SubWord(WORD word)
520{
521 unsigned int result;
522
523 result = (int)aes_sbox[(word >> 4) & 0x0000000F][word & 0x0000000F];
524 result += (int)aes_sbox[(word >> 12) & 0x0000000F][(word >> 8) & 0x0000000F] << 8;
525 result += (int)aes_sbox[(word >> 20) & 0x0000000F][(word >> 16) & 0x0000000F] << 16;
526 result += (int)aes_sbox[(word >> 28) & 0x0000000F][(word >> 24) & 0x0000000F] << 24;
527 return(result);
528}
529
530// Performs the action of generating the keys that will be used in every round of
531// encryption. "key" is the user-supplied input key, "w" is the output key schedule,
532// "keysize" is the length in bits of "key", must be 128, 192, or 256.
533void aes_key_setup(const BYTE key[], WORD w[], int keysize)
534{
535 int Nb=4,Nr,Nk,idx;
536 WORD temp,Rcon[]={0x01000000,0x02000000,0x04000000,0x08000000,0x10000000,0x20000000,
537 0x40000000,0x80000000,0x1b000000,0x36000000,0x6c000000,0xd8000000,
538 0xab000000,0x4d000000,0x9a000000};
539
540 switch (keysize) {
541 case 128: Nr = 10; Nk = 4; break;
542 case 192: Nr = 12; Nk = 6; break;
543 case 256: Nr = 14; Nk = 8; break;
544 default: return;
545 }
546
547 for (idx=0; idx < Nk; ++idx) {
548 w[idx] = ((key[4 * idx]) << 24) | ((key[4 * idx + 1]) << 16) |
549 ((key[4 * idx + 2]) << 8) | ((key[4 * idx + 3]));
550 }
551
552 for (idx = Nk; idx < Nb * (Nr+1); ++idx) {
553 temp = w[idx - 1];
554 if ((idx % Nk) == 0)
555 temp = SubWord(KE_ROTWORD(temp)) ^ Rcon[(idx-1)/Nk];
556 else if (Nk > 6 && (idx % Nk) == 4)
557 temp = SubWord(word: temp);
558 w[idx] = w[idx-Nk] ^ temp;
559 }
560}
561
562/////////////////
563// ADD ROUND KEY
564/////////////////
565
566// Performs the AddRoundKey step. Each round has its own pre-generated 16-byte key in the
567// form of 4 integers (the "w" array). Each integer is XOR'd by one column of the state.
568// Also performs the job of InvAddRoundKey(); since the function is a simple XOR process,
569// it is its own inverse.
570void AddRoundKey(BYTE state[][4], const WORD w[])
571{
572 BYTE subkey[4];
573
574 // memcpy(subkey,&w[idx],4); // Not accurate for big endian machines
575 // Subkey 1
576 subkey[0] = w[0] >> 24;
577 subkey[1] = w[0] >> 16;
578 subkey[2] = w[0] >> 8;
579 subkey[3] = w[0];
580 state[0][0] ^= subkey[0];
581 state[1][0] ^= subkey[1];
582 state[2][0] ^= subkey[2];
583 state[3][0] ^= subkey[3];
584 // Subkey 2
585 subkey[0] = w[1] >> 24;
586 subkey[1] = w[1] >> 16;
587 subkey[2] = w[1] >> 8;
588 subkey[3] = w[1];
589 state[0][1] ^= subkey[0];
590 state[1][1] ^= subkey[1];
591 state[2][1] ^= subkey[2];
592 state[3][1] ^= subkey[3];
593 // Subkey 3
594 subkey[0] = w[2] >> 24;
595 subkey[1] = w[2] >> 16;
596 subkey[2] = w[2] >> 8;
597 subkey[3] = w[2];
598 state[0][2] ^= subkey[0];
599 state[1][2] ^= subkey[1];
600 state[2][2] ^= subkey[2];
601 state[3][2] ^= subkey[3];
602 // Subkey 4
603 subkey[0] = w[3] >> 24;
604 subkey[1] = w[3] >> 16;
605 subkey[2] = w[3] >> 8;
606 subkey[3] = w[3];
607 state[0][3] ^= subkey[0];
608 state[1][3] ^= subkey[1];
609 state[2][3] ^= subkey[2];
610 state[3][3] ^= subkey[3];
611}
612
613/////////////////
614// (Inv)SubBytes
615/////////////////
616
617// Performs the SubBytes step. All bytes in the state are substituted with a
618// pre-calculated value from a lookup table.
619void SubBytes(BYTE state[][4])
620{
621 state[0][0] = aes_sbox[state[0][0] >> 4][state[0][0] & 0x0F];
622 state[0][1] = aes_sbox[state[0][1] >> 4][state[0][1] & 0x0F];
623 state[0][2] = aes_sbox[state[0][2] >> 4][state[0][2] & 0x0F];
624 state[0][3] = aes_sbox[state[0][3] >> 4][state[0][3] & 0x0F];
625 state[1][0] = aes_sbox[state[1][0] >> 4][state[1][0] & 0x0F];
626 state[1][1] = aes_sbox[state[1][1] >> 4][state[1][1] & 0x0F];
627 state[1][2] = aes_sbox[state[1][2] >> 4][state[1][2] & 0x0F];
628 state[1][3] = aes_sbox[state[1][3] >> 4][state[1][3] & 0x0F];
629 state[2][0] = aes_sbox[state[2][0] >> 4][state[2][0] & 0x0F];
630 state[2][1] = aes_sbox[state[2][1] >> 4][state[2][1] & 0x0F];
631 state[2][2] = aes_sbox[state[2][2] >> 4][state[2][2] & 0x0F];
632 state[2][3] = aes_sbox[state[2][3] >> 4][state[2][3] & 0x0F];
633 state[3][0] = aes_sbox[state[3][0] >> 4][state[3][0] & 0x0F];
634 state[3][1] = aes_sbox[state[3][1] >> 4][state[3][1] & 0x0F];
635 state[3][2] = aes_sbox[state[3][2] >> 4][state[3][2] & 0x0F];
636 state[3][3] = aes_sbox[state[3][3] >> 4][state[3][3] & 0x0F];
637}
638
639void InvSubBytes(BYTE state[][4])
640{
641 state[0][0] = aes_invsbox[state[0][0] >> 4][state[0][0] & 0x0F];
642 state[0][1] = aes_invsbox[state[0][1] >> 4][state[0][1] & 0x0F];
643 state[0][2] = aes_invsbox[state[0][2] >> 4][state[0][2] & 0x0F];
644 state[0][3] = aes_invsbox[state[0][3] >> 4][state[0][3] & 0x0F];
645 state[1][0] = aes_invsbox[state[1][0] >> 4][state[1][0] & 0x0F];
646 state[1][1] = aes_invsbox[state[1][1] >> 4][state[1][1] & 0x0F];
647 state[1][2] = aes_invsbox[state[1][2] >> 4][state[1][2] & 0x0F];
648 state[1][3] = aes_invsbox[state[1][3] >> 4][state[1][3] & 0x0F];
649 state[2][0] = aes_invsbox[state[2][0] >> 4][state[2][0] & 0x0F];
650 state[2][1] = aes_invsbox[state[2][1] >> 4][state[2][1] & 0x0F];
651 state[2][2] = aes_invsbox[state[2][2] >> 4][state[2][2] & 0x0F];
652 state[2][3] = aes_invsbox[state[2][3] >> 4][state[2][3] & 0x0F];
653 state[3][0] = aes_invsbox[state[3][0] >> 4][state[3][0] & 0x0F];
654 state[3][1] = aes_invsbox[state[3][1] >> 4][state[3][1] & 0x0F];
655 state[3][2] = aes_invsbox[state[3][2] >> 4][state[3][2] & 0x0F];
656 state[3][3] = aes_invsbox[state[3][3] >> 4][state[3][3] & 0x0F];
657}
658
659/////////////////
660// (Inv)ShiftRows
661/////////////////
662
663// Performs the ShiftRows step. All rows are shifted cylindrically to the left.
664void ShiftRows(BYTE state[][4])
665{
666 int t;
667
668 // Shift left by 1
669 t = state[1][0];
670 state[1][0] = state[1][1];
671 state[1][1] = state[1][2];
672 state[1][2] = state[1][3];
673 state[1][3] = t;
674 // Shift left by 2
675 t = state[2][0];
676 state[2][0] = state[2][2];
677 state[2][2] = t;
678 t = state[2][1];
679 state[2][1] = state[2][3];
680 state[2][3] = t;
681 // Shift left by 3
682 t = state[3][0];
683 state[3][0] = state[3][3];
684 state[3][3] = state[3][2];
685 state[3][2] = state[3][1];
686 state[3][1] = t;
687}
688
689// All rows are shifted cylindrically to the right.
690void InvShiftRows(BYTE state[][4])
691{
692 int t;
693
694 // Shift right by 1
695 t = state[1][3];
696 state[1][3] = state[1][2];
697 state[1][2] = state[1][1];
698 state[1][1] = state[1][0];
699 state[1][0] = t;
700 // Shift right by 2
701 t = state[2][3];
702 state[2][3] = state[2][1];
703 state[2][1] = t;
704 t = state[2][2];
705 state[2][2] = state[2][0];
706 state[2][0] = t;
707 // Shift right by 3
708 t = state[3][3];
709 state[3][3] = state[3][0];
710 state[3][0] = state[3][1];
711 state[3][1] = state[3][2];
712 state[3][2] = t;
713}
714
715/////////////////
716// (Inv)MixColumns
717/////////////////
718
719// Performs the MixColums step. The state is multiplied by itself using matrix
720// multiplication in a Galios Field 2^8. All multiplication is pre-computed in a table.
721// Addition is equivilent to XOR. (Must always make a copy of the column as the original
722// values will be destoyed.)
723void MixColumns(BYTE state[][4])
724{
725 BYTE col[4];
726
727 // Column 1
728 col[0] = state[0][0];
729 col[1] = state[1][0];
730 col[2] = state[2][0];
731 col[3] = state[3][0];
732 state[0][0] = gf_mul[col[0]][0];
733 state[0][0] ^= gf_mul[col[1]][1];
734 state[0][0] ^= col[2];
735 state[0][0] ^= col[3];
736 state[1][0] = col[0];
737 state[1][0] ^= gf_mul[col[1]][0];
738 state[1][0] ^= gf_mul[col[2]][1];
739 state[1][0] ^= col[3];
740 state[2][0] = col[0];
741 state[2][0] ^= col[1];
742 state[2][0] ^= gf_mul[col[2]][0];
743 state[2][0] ^= gf_mul[col[3]][1];
744 state[3][0] = gf_mul[col[0]][1];
745 state[3][0] ^= col[1];
746 state[3][0] ^= col[2];
747 state[3][0] ^= gf_mul[col[3]][0];
748 // Column 2
749 col[0] = state[0][1];
750 col[1] = state[1][1];
751 col[2] = state[2][1];
752 col[3] = state[3][1];
753 state[0][1] = gf_mul[col[0]][0];
754 state[0][1] ^= gf_mul[col[1]][1];
755 state[0][1] ^= col[2];
756 state[0][1] ^= col[3];
757 state[1][1] = col[0];
758 state[1][1] ^= gf_mul[col[1]][0];
759 state[1][1] ^= gf_mul[col[2]][1];
760 state[1][1] ^= col[3];
761 state[2][1] = col[0];
762 state[2][1] ^= col[1];
763 state[2][1] ^= gf_mul[col[2]][0];
764 state[2][1] ^= gf_mul[col[3]][1];
765 state[3][1] = gf_mul[col[0]][1];
766 state[3][1] ^= col[1];
767 state[3][1] ^= col[2];
768 state[3][1] ^= gf_mul[col[3]][0];
769 // Column 3
770 col[0] = state[0][2];
771 col[1] = state[1][2];
772 col[2] = state[2][2];
773 col[3] = state[3][2];
774 state[0][2] = gf_mul[col[0]][0];
775 state[0][2] ^= gf_mul[col[1]][1];
776 state[0][2] ^= col[2];
777 state[0][2] ^= col[3];
778 state[1][2] = col[0];
779 state[1][2] ^= gf_mul[col[1]][0];
780 state[1][2] ^= gf_mul[col[2]][1];
781 state[1][2] ^= col[3];
782 state[2][2] = col[0];
783 state[2][2] ^= col[1];
784 state[2][2] ^= gf_mul[col[2]][0];
785 state[2][2] ^= gf_mul[col[3]][1];
786 state[3][2] = gf_mul[col[0]][1];
787 state[3][2] ^= col[1];
788 state[3][2] ^= col[2];
789 state[3][2] ^= gf_mul[col[3]][0];
790 // Column 4
791 col[0] = state[0][3];
792 col[1] = state[1][3];
793 col[2] = state[2][3];
794 col[3] = state[3][3];
795 state[0][3] = gf_mul[col[0]][0];
796 state[0][3] ^= gf_mul[col[1]][1];
797 state[0][3] ^= col[2];
798 state[0][3] ^= col[3];
799 state[1][3] = col[0];
800 state[1][3] ^= gf_mul[col[1]][0];
801 state[1][3] ^= gf_mul[col[2]][1];
802 state[1][3] ^= col[3];
803 state[2][3] = col[0];
804 state[2][3] ^= col[1];
805 state[2][3] ^= gf_mul[col[2]][0];
806 state[2][3] ^= gf_mul[col[3]][1];
807 state[3][3] = gf_mul[col[0]][1];
808 state[3][3] ^= col[1];
809 state[3][3] ^= col[2];
810 state[3][3] ^= gf_mul[col[3]][0];
811}
812
813void InvMixColumns(BYTE state[][4])
814{
815 BYTE col[4];
816
817 // Column 1
818 col[0] = state[0][0];
819 col[1] = state[1][0];
820 col[2] = state[2][0];
821 col[3] = state[3][0];
822 state[0][0] = gf_mul[col[0]][5];
823 state[0][0] ^= gf_mul[col[1]][3];
824 state[0][0] ^= gf_mul[col[2]][4];
825 state[0][0] ^= gf_mul[col[3]][2];
826 state[1][0] = gf_mul[col[0]][2];
827 state[1][0] ^= gf_mul[col[1]][5];
828 state[1][0] ^= gf_mul[col[2]][3];
829 state[1][0] ^= gf_mul[col[3]][4];
830 state[2][0] = gf_mul[col[0]][4];
831 state[2][0] ^= gf_mul[col[1]][2];
832 state[2][0] ^= gf_mul[col[2]][5];
833 state[2][0] ^= gf_mul[col[3]][3];
834 state[3][0] = gf_mul[col[0]][3];
835 state[3][0] ^= gf_mul[col[1]][4];
836 state[3][0] ^= gf_mul[col[2]][2];
837 state[3][0] ^= gf_mul[col[3]][5];
838 // Column 2
839 col[0] = state[0][1];
840 col[1] = state[1][1];
841 col[2] = state[2][1];
842 col[3] = state[3][1];
843 state[0][1] = gf_mul[col[0]][5];
844 state[0][1] ^= gf_mul[col[1]][3];
845 state[0][1] ^= gf_mul[col[2]][4];
846 state[0][1] ^= gf_mul[col[3]][2];
847 state[1][1] = gf_mul[col[0]][2];
848 state[1][1] ^= gf_mul[col[1]][5];
849 state[1][1] ^= gf_mul[col[2]][3];
850 state[1][1] ^= gf_mul[col[3]][4];
851 state[2][1] = gf_mul[col[0]][4];
852 state[2][1] ^= gf_mul[col[1]][2];
853 state[2][1] ^= gf_mul[col[2]][5];
854 state[2][1] ^= gf_mul[col[3]][3];
855 state[3][1] = gf_mul[col[0]][3];
856 state[3][1] ^= gf_mul[col[1]][4];
857 state[3][1] ^= gf_mul[col[2]][2];
858 state[3][1] ^= gf_mul[col[3]][5];
859 // Column 3
860 col[0] = state[0][2];
861 col[1] = state[1][2];
862 col[2] = state[2][2];
863 col[3] = state[3][2];
864 state[0][2] = gf_mul[col[0]][5];
865 state[0][2] ^= gf_mul[col[1]][3];
866 state[0][2] ^= gf_mul[col[2]][4];
867 state[0][2] ^= gf_mul[col[3]][2];
868 state[1][2] = gf_mul[col[0]][2];
869 state[1][2] ^= gf_mul[col[1]][5];
870 state[1][2] ^= gf_mul[col[2]][3];
871 state[1][2] ^= gf_mul[col[3]][4];
872 state[2][2] = gf_mul[col[0]][4];
873 state[2][2] ^= gf_mul[col[1]][2];
874 state[2][2] ^= gf_mul[col[2]][5];
875 state[2][2] ^= gf_mul[col[3]][3];
876 state[3][2] = gf_mul[col[0]][3];
877 state[3][2] ^= gf_mul[col[1]][4];
878 state[3][2] ^= gf_mul[col[2]][2];
879 state[3][2] ^= gf_mul[col[3]][5];
880 // Column 4
881 col[0] = state[0][3];
882 col[1] = state[1][3];
883 col[2] = state[2][3];
884 col[3] = state[3][3];
885 state[0][3] = gf_mul[col[0]][5];
886 state[0][3] ^= gf_mul[col[1]][3];
887 state[0][3] ^= gf_mul[col[2]][4];
888 state[0][3] ^= gf_mul[col[3]][2];
889 state[1][3] = gf_mul[col[0]][2];
890 state[1][3] ^= gf_mul[col[1]][5];
891 state[1][3] ^= gf_mul[col[2]][3];
892 state[1][3] ^= gf_mul[col[3]][4];
893 state[2][3] = gf_mul[col[0]][4];
894 state[2][3] ^= gf_mul[col[1]][2];
895 state[2][3] ^= gf_mul[col[2]][5];
896 state[2][3] ^= gf_mul[col[3]][3];
897 state[3][3] = gf_mul[col[0]][3];
898 state[3][3] ^= gf_mul[col[1]][4];
899 state[3][3] ^= gf_mul[col[2]][2];
900 state[3][3] ^= gf_mul[col[3]][5];
901}
902
903/////////////////
904// (En/De)Crypt
905/////////////////
906
907void aes_encrypt(const BYTE in[], BYTE out[], const WORD key[], int keysize)
908{
909 BYTE state[4][4];
910
911 // Copy input array (should be 16 bytes long) to a matrix (sequential bytes are ordered
912 // by row, not col) called "state" for processing.
913 // *** Implementation note: The official AES documentation references the state by
914 // column, then row. Accessing an element in C requires row then column. Thus, all state
915 // references in AES must have the column and row indexes reversed for C implementation.
916 state[0][0] = in[0];
917 state[1][0] = in[1];
918 state[2][0] = in[2];
919 state[3][0] = in[3];
920 state[0][1] = in[4];
921 state[1][1] = in[5];
922 state[2][1] = in[6];
923 state[3][1] = in[7];
924 state[0][2] = in[8];
925 state[1][2] = in[9];
926 state[2][2] = in[10];
927 state[3][2] = in[11];
928 state[0][3] = in[12];
929 state[1][3] = in[13];
930 state[2][3] = in[14];
931 state[3][3] = in[15];
932
933 // Perform the necessary number of rounds. The round key is added first.
934 // The last round does not perform the MixColumns step.
935 AddRoundKey(state,w: &key[0]);
936 SubBytes(state); ShiftRows(state); MixColumns(state); AddRoundKey(state,w: &key[4]);
937 SubBytes(state); ShiftRows(state); MixColumns(state); AddRoundKey(state,w: &key[8]);
938 SubBytes(state); ShiftRows(state); MixColumns(state); AddRoundKey(state,w: &key[12]);
939 SubBytes(state); ShiftRows(state); MixColumns(state); AddRoundKey(state,w: &key[16]);
940 SubBytes(state); ShiftRows(state); MixColumns(state); AddRoundKey(state,w: &key[20]);
941 SubBytes(state); ShiftRows(state); MixColumns(state); AddRoundKey(state,w: &key[24]);
942 SubBytes(state); ShiftRows(state); MixColumns(state); AddRoundKey(state,w: &key[28]);
943 SubBytes(state); ShiftRows(state); MixColumns(state); AddRoundKey(state,w: &key[32]);
944 SubBytes(state); ShiftRows(state); MixColumns(state); AddRoundKey(state,w: &key[36]);
945 if (keysize != 128) {
946 SubBytes(state); ShiftRows(state); MixColumns(state); AddRoundKey(state,w: &key[40]);
947 SubBytes(state); ShiftRows(state); MixColumns(state); AddRoundKey(state,w: &key[44]);
948 if (keysize != 192) {
949 SubBytes(state); ShiftRows(state); MixColumns(state); AddRoundKey(state,w: &key[48]);
950 SubBytes(state); ShiftRows(state); MixColumns(state); AddRoundKey(state,w: &key[52]);
951 SubBytes(state); ShiftRows(state); AddRoundKey(state,w: &key[56]);
952 }
953 else {
954 SubBytes(state); ShiftRows(state); AddRoundKey(state,w: &key[48]);
955 }
956 }
957 else {
958 SubBytes(state); ShiftRows(state); AddRoundKey(state,w: &key[40]);
959 }
960
961 // Copy the state to the output array.
962 out[0] = state[0][0];
963 out[1] = state[1][0];
964 out[2] = state[2][0];
965 out[3] = state[3][0];
966 out[4] = state[0][1];
967 out[5] = state[1][1];
968 out[6] = state[2][1];
969 out[7] = state[3][1];
970 out[8] = state[0][2];
971 out[9] = state[1][2];
972 out[10] = state[2][2];
973 out[11] = state[3][2];
974 out[12] = state[0][3];
975 out[13] = state[1][3];
976 out[14] = state[2][3];
977 out[15] = state[3][3];
978}
979
980void aes_decrypt(const BYTE in[], BYTE out[], const WORD key[], int keysize)
981{
982 BYTE state[4][4];
983
984 // Copy the input to the state.
985 state[0][0] = in[0];
986 state[1][0] = in[1];
987 state[2][0] = in[2];
988 state[3][0] = in[3];
989 state[0][1] = in[4];
990 state[1][1] = in[5];
991 state[2][1] = in[6];
992 state[3][1] = in[7];
993 state[0][2] = in[8];
994 state[1][2] = in[9];
995 state[2][2] = in[10];
996 state[3][2] = in[11];
997 state[0][3] = in[12];
998 state[1][3] = in[13];
999 state[2][3] = in[14];
1000 state[3][3] = in[15];
1001
1002 // Perform the necessary number of rounds. The round key is added first.
1003 // The last round does not perform the MixColumns step.
1004 if (keysize > 128) {
1005 if (keysize > 192) {
1006 AddRoundKey(state,w: &key[56]);
1007 InvShiftRows(state);InvSubBytes(state);AddRoundKey(state,w: &key[52]);InvMixColumns(state);
1008 InvShiftRows(state);InvSubBytes(state);AddRoundKey(state,w: &key[48]);InvMixColumns(state);
1009 }
1010 else {
1011 AddRoundKey(state,w: &key[48]);
1012 }
1013 InvShiftRows(state);InvSubBytes(state);AddRoundKey(state,w: &key[44]);InvMixColumns(state);
1014 InvShiftRows(state);InvSubBytes(state);AddRoundKey(state,w: &key[40]);InvMixColumns(state);
1015 }
1016 else {
1017 AddRoundKey(state,w: &key[40]);
1018 }
1019 InvShiftRows(state);InvSubBytes(state);AddRoundKey(state,w: &key[36]);InvMixColumns(state);
1020 InvShiftRows(state);InvSubBytes(state);AddRoundKey(state,w: &key[32]);InvMixColumns(state);
1021 InvShiftRows(state);InvSubBytes(state);AddRoundKey(state,w: &key[28]);InvMixColumns(state);
1022 InvShiftRows(state);InvSubBytes(state);AddRoundKey(state,w: &key[24]);InvMixColumns(state);
1023 InvShiftRows(state);InvSubBytes(state);AddRoundKey(state,w: &key[20]);InvMixColumns(state);
1024 InvShiftRows(state);InvSubBytes(state);AddRoundKey(state,w: &key[16]);InvMixColumns(state);
1025 InvShiftRows(state);InvSubBytes(state);AddRoundKey(state,w: &key[12]);InvMixColumns(state);
1026 InvShiftRows(state);InvSubBytes(state);AddRoundKey(state,w: &key[8]);InvMixColumns(state);
1027 InvShiftRows(state);InvSubBytes(state);AddRoundKey(state,w: &key[4]);InvMixColumns(state);
1028 InvShiftRows(state);InvSubBytes(state);AddRoundKey(state,w: &key[0]);
1029
1030 // Copy the state to the output array.
1031 out[0] = state[0][0];
1032 out[1] = state[1][0];
1033 out[2] = state[2][0];
1034 out[3] = state[3][0];
1035 out[4] = state[0][1];
1036 out[5] = state[1][1];
1037 out[6] = state[2][1];
1038 out[7] = state[3][1];
1039 out[8] = state[0][2];
1040 out[9] = state[1][2];
1041 out[10] = state[2][2];
1042 out[11] = state[3][2];
1043 out[12] = state[0][3];
1044 out[13] = state[1][3];
1045 out[14] = state[2][3];
1046 out[15] = state[3][3];
1047}
1048
1049/*******************
1050** AES DEBUGGING FUNCTIONS
1051*******************/
1052/*
1053// This prints the "state" grid as a linear hex string.
1054void print_state(BYTE state[][4])
1055{
1056 int idx,idx2;
1057
1058 for (idx=0; idx < 4; idx++)
1059 for (idx2=0; idx2 < 4; idx2++)
1060 printf("%02x",state[idx2][idx]);
1061 printf("\n");
1062}
1063
1064// This prints the key (4 consecutive ints) used for a given round as a linear hex string.
1065void print_rnd_key(WORD key[])
1066{
1067 int idx;
1068
1069 for (idx=0; idx < 4; idx++)
1070 printf("%08x",key[idx]);
1071 printf("\n");
1072}
1073*/
1074