1/* Aes.c -- AES encryption / decryption
22013-11-12 : Igor Pavlov : Public domain */
3
4#include "Precomp.h"
5
6#include "Aes.h"
7#include "CpuArch.h"
8
9static UInt32 T[256 * 4];
10static Byte Sbox[256] = {
11  0x63, 0x7c, 0x77, 0x7b, 0xf2, 0x6b, 0x6f, 0xc5, 0x30, 0x01, 0x67, 0x2b, 0xfe, 0xd7, 0xab, 0x76,
12  0xca, 0x82, 0xc9, 0x7d, 0xfa, 0x59, 0x47, 0xf0, 0xad, 0xd4, 0xa2, 0xaf, 0x9c, 0xa4, 0x72, 0xc0,
13  0xb7, 0xfd, 0x93, 0x26, 0x36, 0x3f, 0xf7, 0xcc, 0x34, 0xa5, 0xe5, 0xf1, 0x71, 0xd8, 0x31, 0x15,
14  0x04, 0xc7, 0x23, 0xc3, 0x18, 0x96, 0x05, 0x9a, 0x07, 0x12, 0x80, 0xe2, 0xeb, 0x27, 0xb2, 0x75,
15  0x09, 0x83, 0x2c, 0x1a, 0x1b, 0x6e, 0x5a, 0xa0, 0x52, 0x3b, 0xd6, 0xb3, 0x29, 0xe3, 0x2f, 0x84,
16  0x53, 0xd1, 0x00, 0xed, 0x20, 0xfc, 0xb1, 0x5b, 0x6a, 0xcb, 0xbe, 0x39, 0x4a, 0x4c, 0x58, 0xcf,
17  0xd0, 0xef, 0xaa, 0xfb, 0x43, 0x4d, 0x33, 0x85, 0x45, 0xf9, 0x02, 0x7f, 0x50, 0x3c, 0x9f, 0xa8,
18  0x51, 0xa3, 0x40, 0x8f, 0x92, 0x9d, 0x38, 0xf5, 0xbc, 0xb6, 0xda, 0x21, 0x10, 0xff, 0xf3, 0xd2,
19  0xcd, 0x0c, 0x13, 0xec, 0x5f, 0x97, 0x44, 0x17, 0xc4, 0xa7, 0x7e, 0x3d, 0x64, 0x5d, 0x19, 0x73,
20  0x60, 0x81, 0x4f, 0xdc, 0x22, 0x2a, 0x90, 0x88, 0x46, 0xee, 0xb8, 0x14, 0xde, 0x5e, 0x0b, 0xdb,
21  0xe0, 0x32, 0x3a, 0x0a, 0x49, 0x06, 0x24, 0x5c, 0xc2, 0xd3, 0xac, 0x62, 0x91, 0x95, 0xe4, 0x79,
22  0xe7, 0xc8, 0x37, 0x6d, 0x8d, 0xd5, 0x4e, 0xa9, 0x6c, 0x56, 0xf4, 0xea, 0x65, 0x7a, 0xae, 0x08,
23  0xba, 0x78, 0x25, 0x2e, 0x1c, 0xa6, 0xb4, 0xc6, 0xe8, 0xdd, 0x74, 0x1f, 0x4b, 0xbd, 0x8b, 0x8a,
24  0x70, 0x3e, 0xb5, 0x66, 0x48, 0x03, 0xf6, 0x0e, 0x61, 0x35, 0x57, 0xb9, 0x86, 0xc1, 0x1d, 0x9e,
25  0xe1, 0xf8, 0x98, 0x11, 0x69, 0xd9, 0x8e, 0x94, 0x9b, 0x1e, 0x87, 0xe9, 0xce, 0x55, 0x28, 0xdf,
26  0x8c, 0xa1, 0x89, 0x0d, 0xbf, 0xe6, 0x42, 0x68, 0x41, 0x99, 0x2d, 0x0f, 0xb0, 0x54, 0xbb, 0x16};
27
28void MY_FAST_CALL AesCbc_Encode(UInt32 *ivAes, Byte *data, size_t numBlocks);
29void MY_FAST_CALL AesCbc_Decode(UInt32 *ivAes, Byte *data, size_t numBlocks);
30void MY_FAST_CALL AesCtr_Code(UInt32 *ivAes, Byte *data, size_t numBlocks);
31
32void MY_FAST_CALL AesCbc_Encode_Intel(UInt32 *ivAes, Byte *data, size_t numBlocks);
33void MY_FAST_CALL AesCbc_Decode_Intel(UInt32 *ivAes, Byte *data, size_t numBlocks);
34void MY_FAST_CALL AesCtr_Code_Intel(UInt32 *ivAes, Byte *data, size_t numBlocks);
35
36AES_CODE_FUNC g_AesCbc_Encode;
37AES_CODE_FUNC g_AesCbc_Decode;
38AES_CODE_FUNC g_AesCtr_Code;
39
40static UInt32 D[256 * 4];
41static Byte InvS[256];
42
43static Byte Rcon[11] = { 0x00, 0x01, 0x02, 0x04, 0x08, 0x10, 0x20, 0x40, 0x80, 0x1b, 0x36 };
44
45#define xtime(x) ((((x) << 1) ^ (((x) & 0x80) != 0 ? 0x1B : 0)) & 0xFF)
46
47#define Ui32(a0, a1, a2, a3) ((UInt32)(a0) | ((UInt32)(a1) << 8) | ((UInt32)(a2) << 16) | ((UInt32)(a3) << 24))
48
49#define gb0(x) ( (x)          & 0xFF)
50#define gb1(x) (((x) >> ( 8)) & 0xFF)
51#define gb2(x) (((x) >> (16)) & 0xFF)
52#define gb3(x) (((x) >> (24)) & 0xFF)
53
54void AesGenTables(void)
55{
56  unsigned i;
57  for (i = 0; i < 256; i++)
58    InvS[Sbox[i]] = (Byte)i;
59  for (i = 0; i < 256; i++)
60  {
61    {
62      UInt32 a1 = Sbox[i];
63      UInt32 a2 = xtime(a1);
64      UInt32 a3 = a2 ^ a1;
65      T[        i] = Ui32(a2, a1, a1, a3);
66      T[0x100 + i] = Ui32(a3, a2, a1, a1);
67      T[0x200 + i] = Ui32(a1, a3, a2, a1);
68      T[0x300 + i] = Ui32(a1, a1, a3, a2);
69    }
70    {
71      UInt32 a1 = InvS[i];
72      UInt32 a2 = xtime(a1);
73      UInt32 a4 = xtime(a2);
74      UInt32 a8 = xtime(a4);
75      UInt32 a9 = a8 ^ a1;
76      UInt32 aB = a8 ^ a2 ^ a1;
77      UInt32 aD = a8 ^ a4 ^ a1;
78      UInt32 aE = a8 ^ a4 ^ a2;
79      D[        i] = Ui32(aE, a9, aD, aB);
80      D[0x100 + i] = Ui32(aB, aE, a9, aD);
81      D[0x200 + i] = Ui32(aD, aB, aE, a9);
82      D[0x300 + i] = Ui32(a9, aD, aB, aE);
83    }
84  }
85  g_AesCbc_Encode = AesCbc_Encode;
86  g_AesCbc_Decode = AesCbc_Decode;
87  g_AesCtr_Code = AesCtr_Code;
88  #ifdef MY_CPU_X86_OR_AMD64
89  if (CPU_Is_Aes_Supported())
90  {
91    g_AesCbc_Encode = AesCbc_Encode_Intel;
92    g_AesCbc_Decode = AesCbc_Decode_Intel;
93    g_AesCtr_Code = AesCtr_Code_Intel;
94  }
95  #endif
96}
97
98#define HT(i, x, s) (T + (x << 8))[gb ## x(s[(i + x) & 3])]
99#define HT4(m, i, s, p) m[i] = \
100    HT(i, 0, s) ^ \
101    HT(i, 1, s) ^ \
102    HT(i, 2, s) ^ \
103    HT(i, 3, s) ^ w[p + i]
104/* such order (2031) in HT16 is for VC6/K8 speed optimization) */
105#define HT16(m, s, p) \
106    HT4(m, 2, s, p); \
107    HT4(m, 0, s, p); \
108    HT4(m, 3, s, p); \
109    HT4(m, 1, s, p); \
110
111#define FT(i, x) Sbox[gb ## x(m[(i + x) & 3])]
112#define FT4(i) dest[i] = Ui32(FT(i, 0), FT(i, 1), FT(i, 2), FT(i, 3)) ^ w[i];
113
114#define HD(i, x, s) (D + (x << 8))[gb ## x(s[(i - x) & 3])]
115#define HD4(m, i, s, p) m[i] = \
116    HD(i, 0, s) ^ \
117    HD(i, 1, s) ^ \
118    HD(i, 2, s) ^ \
119    HD(i, 3, s) ^ w[p + i];
120/* such order (0231) in HD16 is for VC6/K8 speed optimization) */
121#define HD16(m, s, p) \
122    HD4(m, 0, s, p); \
123    HD4(m, 2, s, p); \
124    HD4(m, 3, s, p); \
125    HD4(m, 1, s, p); \
126
127#define FD(i, x) InvS[gb ## x(m[(i - x) & 3])]
128#define FD4(i) dest[i] = Ui32(FD(i, 0), FD(i, 1), FD(i, 2), FD(i, 3)) ^ w[i];
129
130void MY_FAST_CALL Aes_SetKey_Enc(UInt32 *w, const Byte *key, unsigned keySize)
131{
132  unsigned i, wSize;
133  wSize = keySize + 28;
134  keySize /= 4;
135  w[0] = ((UInt32)keySize / 2) + 3;
136  w += 4;
137
138  for (i = 0; i < keySize; i++, key += 4)
139    w[i] = GetUi32(key);
140
141  for (; i < wSize; i++)
142  {
143    UInt32 t = w[i - 1];
144    unsigned rem = i % keySize;
145    if (rem == 0)
146      t = Ui32(Sbox[gb1(t)] ^ Rcon[i / keySize], Sbox[gb2(t)], Sbox[gb3(t)], Sbox[gb0(t)]);
147    else if (keySize > 6 && rem == 4)
148      t = Ui32(Sbox[gb0(t)], Sbox[gb1(t)], Sbox[gb2(t)], Sbox[gb3(t)]);
149    w[i] = w[i - keySize] ^ t;
150  }
151}
152
153void MY_FAST_CALL Aes_SetKey_Dec(UInt32 *w, const Byte *key, unsigned keySize)
154{
155  unsigned i, num;
156  Aes_SetKey_Enc(w, key, keySize);
157  num = keySize + 20;
158  w += 8;
159  for (i = 0; i < num; i++)
160  {
161    UInt32 r = w[i];
162    w[i] =
163      D[        Sbox[gb0(r)]] ^
164      D[0x100 + Sbox[gb1(r)]] ^
165      D[0x200 + Sbox[gb2(r)]] ^
166      D[0x300 + Sbox[gb3(r)]];
167  }
168}
169
170/* Aes_Encode and Aes_Decode functions work with little-endian words.
171  src and dest are pointers to 4 UInt32 words.
172  arc and dest can point to same block */
173
174static void Aes_Encode(const UInt32 *w, UInt32 *dest, const UInt32 *src)
175{
176  UInt32 s[4];
177  UInt32 m[4];
178  UInt32 numRounds2 = w[0];
179  w += 4;
180  s[0] = src[0] ^ w[0];
181  s[1] = src[1] ^ w[1];
182  s[2] = src[2] ^ w[2];
183  s[3] = src[3] ^ w[3];
184  w += 4;
185  for (;;)
186  {
187    HT16(m, s, 0);
188    if (--numRounds2 == 0)
189      break;
190    HT16(s, m, 4);
191    w += 8;
192  }
193  w += 4;
194  FT4(0); FT4(1); FT4(2); FT4(3);
195}
196
197static void Aes_Decode(const UInt32 *w, UInt32 *dest, const UInt32 *src)
198{
199  UInt32 s[4];
200  UInt32 m[4];
201  UInt32 numRounds2 = w[0];
202  w += 4 + numRounds2 * 8;
203  s[0] = src[0] ^ w[0];
204  s[1] = src[1] ^ w[1];
205  s[2] = src[2] ^ w[2];
206  s[3] = src[3] ^ w[3];
207  for (;;)
208  {
209    w -= 8;
210    HD16(m, s, 4);
211    if (--numRounds2 == 0)
212      break;
213    HD16(s, m, 0);
214  }
215  FD4(0); FD4(1); FD4(2); FD4(3);
216}
217
218void AesCbc_Init(UInt32 *p, const Byte *iv)
219{
220  unsigned i;
221  for (i = 0; i < 4; i++)
222    p[i] = GetUi32(iv + i * 4);
223}
224
225void MY_FAST_CALL AesCbc_Encode(UInt32 *p, Byte *data, size_t numBlocks)
226{
227  for (; numBlocks != 0; numBlocks--, data += AES_BLOCK_SIZE)
228  {
229    p[0] ^= GetUi32(data);
230    p[1] ^= GetUi32(data + 4);
231    p[2] ^= GetUi32(data + 8);
232    p[3] ^= GetUi32(data + 12);
233
234    Aes_Encode(p + 4, p, p);
235
236    SetUi32(data,      p[0]);
237    SetUi32(data + 4,  p[1]);
238    SetUi32(data + 8,  p[2]);
239    SetUi32(data + 12, p[3]);
240  }
241}
242
243void MY_FAST_CALL AesCbc_Decode(UInt32 *p, Byte *data, size_t numBlocks)
244{
245  UInt32 in[4], out[4];
246  for (; numBlocks != 0; numBlocks--, data += AES_BLOCK_SIZE)
247  {
248    in[0] = GetUi32(data);
249    in[1] = GetUi32(data + 4);
250    in[2] = GetUi32(data + 8);
251    in[3] = GetUi32(data + 12);
252
253    Aes_Decode(p + 4, out, in);
254
255    SetUi32(data,      p[0] ^ out[0]);
256    SetUi32(data + 4,  p[1] ^ out[1]);
257    SetUi32(data + 8,  p[2] ^ out[2]);
258    SetUi32(data + 12, p[3] ^ out[3]);
259
260    p[0] = in[0];
261    p[1] = in[1];
262    p[2] = in[2];
263    p[3] = in[3];
264  }
265}
266
267void MY_FAST_CALL AesCtr_Code(UInt32 *p, Byte *data, size_t numBlocks)
268{
269  for (; numBlocks != 0; numBlocks--)
270  {
271    UInt32 temp[4];
272    Byte buf[16];
273    int i;
274    if (++p[0] == 0)
275      p[1]++;
276    Aes_Encode(p + 4, temp, p);
277    SetUi32(buf,      temp[0]);
278    SetUi32(buf + 4,  temp[1]);
279    SetUi32(buf + 8,  temp[2]);
280    SetUi32(buf + 12, temp[3]);
281    for (i = 0; i < 16; i++)
282      *data++ ^= buf[i];
283  }
284}
285