1 /* Aes.c -- AES encryption / decryption
2 2008-08-05
3 Igor Pavlov
4 Public domain */
5
6 #include "Aes.h"
7 #include "CpuArch.h"
8
9 static UInt32 T[256 * 4];
10 static 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
28 static UInt32 D[256 * 4];
29 static Byte InvS[256];
30
31 static Byte Rcon[11] = { 0x00, 0x01, 0x02, 0x04, 0x08, 0x10, 0x20, 0x40, 0x80, 0x1b, 0x36 };
32
33 #define xtime(x) ((((x) << 1) ^ (((x) & 0x80) != 0 ? 0x1B : 0)) & 0xFF)
34
35 #define Ui32(a0, a1, a2, a3) ((UInt32)(a0) | ((UInt32)(a1) << 8) | ((UInt32)(a2) << 16) | ((UInt32)(a3) << 24))
36
37 #define gb0(x) ( (x) & 0xFF)
38 #define gb1(x) (((x) >> ( 8)) & 0xFF)
39 #define gb2(x) (((x) >> (16)) & 0xFF)
40 #define gb3(x) (((x) >> (24)) & 0xFF)
41
AesGenTables(void)42 void AesGenTables(void)
43 {
44 unsigned i;
45 for (i = 0; i < 256; i++)
46 InvS[Sbox[i]] = (Byte)i;
47 for (i = 0; i < 256; i++)
48 {
49 {
50 UInt32 a1 = Sbox[i];
51 UInt32 a2 = xtime(a1);
52 UInt32 a3 = xtime(a1) ^ a1;
53 T[ i] = Ui32(a2, a1, a1, a3);
54 T[0x100 + i] = Ui32(a3, a2, a1, a1);
55 T[0x200 + i] = Ui32(a1, a3, a2, a1);
56 T[0x300 + i] = Ui32(a1, a1, a3, a2);
57 }
58 {
59 UInt32 a1 = InvS[i];
60 UInt32 a2 = xtime(a1);
61 UInt32 a4 = xtime(a2);
62 UInt32 a8 = xtime(a4);
63 UInt32 a9 = a8 ^ a1;
64 UInt32 aB = a8 ^ a2 ^ a1;
65 UInt32 aD = a8 ^ a4 ^ a1;
66 UInt32 aE = a8 ^ a4 ^ a2;
67 D[ i] = Ui32(aE, a9, aD, aB);
68 D[0x100 + i] = Ui32(aB, aE, a9, aD);
69 D[0x200 + i] = Ui32(aD, aB, aE, a9);
70 D[0x300 + i] = Ui32(a9, aD, aB, aE);
71 }
72 }
73 }
74
75 #define HT(i, x, s) (T + (x << 8))[gb ## x(s[(i + x) & 3])]
76 #define HT4(m, i, s, p) m[i] = \
77 HT(i, 0, s) ^ \
78 HT(i, 1, s) ^ \
79 HT(i, 2, s) ^ \
80 HT(i, 3, s) ^ w[p + i]
81 /* such order (2031) in HT16 is for VC6/K8 speed optimization) */
82 #define HT16(m, s, p) \
83 HT4(m, 2, s, p); \
84 HT4(m, 0, s, p); \
85 HT4(m, 3, s, p); \
86 HT4(m, 1, s, p); \
87
88 #define FT(i, x) Sbox[gb ## x(m[(i + x) & 3])]
89 #define FT4(i) dest[i] = Ui32(FT(i, 0), FT(i, 1), FT(i, 2), FT(i, 3)) ^ w[i];
90
91 #define HD(i, x, s) (D + (x << 8))[gb ## x(s[(i - x) & 3])]
92 #define HD4(m, i, s, p) m[i] = \
93 HD(i, 0, s) ^ \
94 HD(i, 1, s) ^ \
95 HD(i, 2, s) ^ \
96 HD(i, 3, s) ^ w[p + i];
97 /* such order (0231) in HD16 is for VC6/K8 speed optimization) */
98 #define HD16(m, s, p) \
99 HD4(m, 0, s, p); \
100 HD4(m, 2, s, p); \
101 HD4(m, 3, s, p); \
102 HD4(m, 1, s, p); \
103
104 #define FD(i, x) InvS[gb ## x(m[(i - x) & 3])]
105 #define FD4(i) dest[i] = Ui32(FD(i, 0), FD(i, 1), FD(i, 2), FD(i, 3)) ^ w[i];
106
Aes_SetKeyEncode(CAes * p,const Byte * key,unsigned keySize)107 void Aes_SetKeyEncode(CAes *p, const Byte *key, unsigned keySize)
108 {
109 unsigned i, wSize;
110 UInt32 *w;
111 keySize /= 4;
112 p->numRounds2 = keySize / 2 + 3;
113
114 wSize = (p->numRounds2 * 2 + 1) * 4;
115 w = p->rkey;
116
117 for (i = 0; i < keySize; i++, key += 4)
118 w[i] = Ui32(key[0], key[1], key[2], key[3]);
119
120 for (; i < wSize; i++)
121 {
122 UInt32 t = w[i - 1];
123 unsigned rem = i % keySize;
124 if (rem == 0)
125 t = Ui32(Sbox[gb1(t)] ^ Rcon[i / keySize], Sbox[gb2(t)], Sbox[gb3(t)], Sbox[gb0(t)]);
126 else if (keySize > 6 && rem == 4)
127 t = Ui32(Sbox[gb0(t)], Sbox[gb1(t)], Sbox[gb2(t)], Sbox[gb3(t)]);
128 w[i] = w[i - keySize] ^ t;
129 }
130 }
131
Aes_SetKeyDecode(CAes * p,const Byte * key,unsigned keySize)132 void Aes_SetKeyDecode(CAes *p, const Byte *key, unsigned keySize)
133 {
134 unsigned i, num;
135 UInt32 *w;
136 Aes_SetKeyEncode(p, key, keySize);
137 num = p->numRounds2 * 8 - 4;
138 w = p->rkey + 4;
139 for (i = 0; i < num; i++)
140 {
141 UInt32 r = w[i];
142 w[i] =
143 D[ Sbox[gb0(r)]] ^
144 D[0x100 + Sbox[gb1(r)]] ^
145 D[0x200 + Sbox[gb2(r)]] ^
146 D[0x300 + Sbox[gb3(r)]];
147 }
148 }
149
AesEncode32(UInt32 * dest,const UInt32 * src,const UInt32 * w,unsigned numRounds2)150 static void AesEncode32(UInt32 *dest, const UInt32 *src, const UInt32 *w, unsigned numRounds2)
151 {
152 UInt32 s[4];
153 UInt32 m[4];
154 s[0] = src[0] ^ w[0];
155 s[1] = src[1] ^ w[1];
156 s[2] = src[2] ^ w[2];
157 s[3] = src[3] ^ w[3];
158 w += 4;
159 for (;;)
160 {
161 HT16(m, s, 0);
162 if (--numRounds2 == 0)
163 break;
164 HT16(s, m, 4);
165 w += 8;
166 }
167 w += 4;
168 FT4(0); FT4(1); FT4(2); FT4(3);
169 }
170
AesDecode32(UInt32 * dest,const UInt32 * src,const UInt32 * w,unsigned numRounds2)171 static void AesDecode32(UInt32 *dest, const UInt32 *src, const UInt32 *w, unsigned numRounds2)
172 {
173 UInt32 s[4];
174 UInt32 m[4];
175 w += numRounds2 * 8;
176 s[0] = src[0] ^ w[0];
177 s[1] = src[1] ^ w[1];
178 s[2] = src[2] ^ w[2];
179 s[3] = src[3] ^ w[3];
180 for (;;)
181 {
182 w -= 8;
183 HD16(m, s, 4);
184 if (--numRounds2 == 0)
185 break;
186 HD16(s, m, 0);
187 }
188 FD4(0); FD4(1); FD4(2); FD4(3);
189 }
190
Aes_Encode32(const CAes * p,UInt32 * dest,const UInt32 * src)191 void Aes_Encode32(const CAes *p, UInt32 *dest, const UInt32 *src)
192 {
193 AesEncode32(dest, src, p->rkey, p->numRounds2);
194 }
195
Aes_Decode32(const CAes * p,UInt32 * dest,const UInt32 * src)196 void Aes_Decode32(const CAes *p, UInt32 *dest, const UInt32 *src)
197 {
198 AesDecode32(dest, src, p->rkey, p->numRounds2);
199 }
200
AesCbc_Init(CAesCbc * p,const Byte * iv)201 void AesCbc_Init(CAesCbc *p, const Byte *iv)
202 {
203 unsigned i;
204 for (i = 0; i < 4; i++)
205 p->prev[i] = GetUi32(iv + i * 4);
206 }
207
AesCbc_Encode(CAesCbc * p,Byte * data,SizeT size)208 SizeT AesCbc_Encode(CAesCbc *p, Byte *data, SizeT size)
209 {
210 SizeT i;
211 if (size == 0)
212 return 0;
213 if (size < AES_BLOCK_SIZE)
214 return AES_BLOCK_SIZE;
215 size -= AES_BLOCK_SIZE;
216 for (i = 0; i <= size; i += AES_BLOCK_SIZE, data += AES_BLOCK_SIZE)
217 {
218 p->prev[0] ^= GetUi32(data);
219 p->prev[1] ^= GetUi32(data + 4);
220 p->prev[2] ^= GetUi32(data + 8);
221 p->prev[3] ^= GetUi32(data + 12);
222
223 AesEncode32(p->prev, p->prev, p->aes.rkey, p->aes.numRounds2);
224
225 SetUi32(data, p->prev[0]);
226 SetUi32(data + 4, p->prev[1]);
227 SetUi32(data + 8, p->prev[2]);
228 SetUi32(data + 12, p->prev[3]);
229 }
230 return i;
231 }
232
AesCbc_Decode(CAesCbc * p,Byte * data,SizeT size)233 SizeT AesCbc_Decode(CAesCbc *p, Byte *data, SizeT size)
234 {
235 SizeT i;
236 UInt32 in[4], out[4];
237 if (size == 0)
238 return 0;
239 if (size < AES_BLOCK_SIZE)
240 return AES_BLOCK_SIZE;
241 size -= AES_BLOCK_SIZE;
242 for (i = 0; i <= size; i += AES_BLOCK_SIZE, data += AES_BLOCK_SIZE)
243 {
244 in[0] = GetUi32(data);
245 in[1] = GetUi32(data + 4);
246 in[2] = GetUi32(data + 8);
247 in[3] = GetUi32(data + 12);
248
249 AesDecode32(out, in, p->aes.rkey, p->aes.numRounds2);
250
251 SetUi32(data, p->prev[0] ^ out[0]);
252 SetUi32(data + 4, p->prev[1] ^ out[1]);
253 SetUi32(data + 8, p->prev[2] ^ out[2]);
254 SetUi32(data + 12, p->prev[3] ^ out[3]);
255
256 p->prev[0] = in[0];
257 p->prev[1] = in[1];
258 p->prev[2] = in[2];
259 p->prev[3] = in[3];
260 }
261 return i;
262 }
263