This source file includes following definitions.
- to_uchar
- arctwo_encrypt
- arctwo_decrypt
- arctwo_setkey_ekb
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28 #include <config.h>
29
30 #include "arctwo.h"
31
32 #include "bitrotate.h"
33
34 static const uint8_t arctwo_sbox[] = {
35 217, 120, 249, 196, 25, 221, 181, 237,
36 40, 233, 253, 121, 74, 160, 216, 157,
37 198, 126, 55, 131, 43, 118, 83, 142,
38 98, 76, 100, 136, 68, 139, 251, 162,
39 23, 154, 89, 245, 135, 179, 79, 19,
40 97, 69, 109, 141, 9, 129, 125, 50,
41 189, 143, 64, 235, 134, 183, 123, 11,
42 240, 149, 33, 34, 92, 107, 78, 130,
43 84, 214, 101, 147, 206, 96, 178, 28,
44 115, 86, 192, 20, 167, 140, 241, 220,
45 18, 117, 202, 31, 59, 190, 228, 209,
46 66, 61, 212, 48, 163, 60, 182, 38,
47 111, 191, 14, 218, 70, 105, 7, 87,
48 39, 242, 29, 155, 188, 148, 67, 3,
49 248, 17, 199, 246, 144, 239, 62, 231,
50 6, 195, 213, 47, 200, 102, 30, 215,
51 8, 232, 234, 222, 128, 82, 238, 247,
52 132, 170, 114, 172, 53, 77, 106, 42,
53 150, 26, 210, 113, 90, 21, 73, 116,
54 75, 159, 208, 94, 4, 24, 164, 236,
55 194, 224, 65, 110, 15, 81, 203, 204,
56 36, 145, 175, 80, 161, 244, 112, 57,
57 153, 124, 58, 133, 35, 184, 180, 122,
58 252, 2, 54, 91, 37, 85, 151, 49,
59 45, 93, 250, 152, 227, 138, 146, 174,
60 5, 223, 41, 16, 103, 108, 186, 201,
61 211, 0, 230, 207, 225, 158, 168, 44,
62 99, 22, 1, 63, 88, 226, 137, 169,
63 13, 56, 52, 27, 171, 51, 255, 176,
64 187, 72, 12, 95, 185, 177, 205, 46,
65 197, 243, 219, 71, 229, 165, 156, 119,
66 10, 166, 32, 104, 254, 127, 193, 173
67 };
68
69
70 static unsigned char
71 to_uchar (char ch)
72 {
73 return ch;
74 }
75
76 void
77 arctwo_encrypt (arctwo_context *context, const char *inbuf,
78 char *outbuf, size_t length)
79 {
80 for (; length >= ARCTWO_BLOCK_SIZE; length -= ARCTWO_BLOCK_SIZE,
81 inbuf += ARCTWO_BLOCK_SIZE, outbuf += ARCTWO_BLOCK_SIZE)
82 {
83 size_t i, j;
84 uint16_t word0 = 0, word1 = 0, word2 = 0, word3 = 0;
85
86 word0 = (word0 << 8) | to_uchar (inbuf[1]);
87 word0 = (word0 << 8) | to_uchar (inbuf[0]);
88 word1 = (word1 << 8) | to_uchar (inbuf[3]);
89 word1 = (word1 << 8) | to_uchar (inbuf[2]);
90 word2 = (word2 << 8) | to_uchar (inbuf[5]);
91 word2 = (word2 << 8) | to_uchar (inbuf[4]);
92 word3 = (word3 << 8) | to_uchar (inbuf[7]);
93 word3 = (word3 << 8) | to_uchar (inbuf[6]);
94
95 for (i = 0; i < 16; i++)
96 {
97 j = i * 4;
98
99 word0 += (word1 & ~word3) + (word2 & word3) + context->S[j];
100 word0 = rotl16 (word0, 1);
101
102 word1 += (word2 & ~word0) + (word3 & word0) + context->S[j + 1];
103 word1 = rotl16 (word1, 2);
104
105 word2 += (word3 & ~word1) + (word0 & word1) + context->S[j + 2];
106 word2 = rotl16 (word2, 3);
107
108 word3 += (word0 & ~word2) + (word1 & word2) + context->S[j + 3];
109 word3 = rotl16 (word3, 5);
110
111 if (i == 4 || i == 10)
112 {
113 word0 += context->S[word3 & 63];
114 word1 += context->S[word0 & 63];
115 word2 += context->S[word1 & 63];
116 word3 += context->S[word2 & 63];
117 }
118 }
119
120 outbuf[0] = word0 & 255;
121 outbuf[1] = word0 >> 8;
122 outbuf[2] = word1 & 255;
123 outbuf[3] = word1 >> 8;
124 outbuf[4] = word2 & 255;
125 outbuf[5] = word2 >> 8;
126 outbuf[6] = word3 & 255;
127 outbuf[7] = word3 >> 8;
128 }
129 }
130
131 void
132 arctwo_decrypt (arctwo_context *context, const char *inbuf,
133 char *outbuf, size_t length)
134 {
135 for (; length >= ARCTWO_BLOCK_SIZE; length -= ARCTWO_BLOCK_SIZE,
136 inbuf += ARCTWO_BLOCK_SIZE, outbuf += ARCTWO_BLOCK_SIZE)
137 {
138 size_t i, j;
139 uint16_t word0 = 0, word1 = 0, word2 = 0, word3 = 0;
140
141 word0 = (word0 << 8) | to_uchar (inbuf[1]);
142 word0 = (word0 << 8) | to_uchar (inbuf[0]);
143 word1 = (word1 << 8) | to_uchar (inbuf[3]);
144 word1 = (word1 << 8) | to_uchar (inbuf[2]);
145 word2 = (word2 << 8) | to_uchar (inbuf[5]);
146 word2 = (word2 << 8) | to_uchar (inbuf[4]);
147 word3 = (word3 << 8) | to_uchar (inbuf[7]);
148 word3 = (word3 << 8) | to_uchar (inbuf[6]);
149
150 for (i = 16; i > 0; i--)
151 {
152 j = (i - 1) * 4;
153
154 word3 = rotr16 (word3, 5);
155 word3 -= (word0 & ~word2) + (word1 & word2) + context->S[j + 3];
156
157 word2 = rotr16 (word2, 3);
158 word2 -= (word3 & ~word1) + (word0 & word1) + context->S[j + 2];
159
160 word1 = rotr16 (word1, 2);
161 word1 -= (word2 & ~word0) + (word3 & word0) + context->S[j + 1];
162
163 word0 = rotr16 (word0, 1);
164 word0 -= (word1 & ~word3) + (word2 & word3) + context->S[j];
165
166 if (i == 6 || i == 12)
167 {
168 word3 = word3 - context->S[word2 & 63];
169 word2 = word2 - context->S[word1 & 63];
170 word1 = word1 - context->S[word0 & 63];
171 word0 = word0 - context->S[word3 & 63];
172 }
173 }
174
175 outbuf[0] = word0 & 255;
176 outbuf[1] = word0 >> 8;
177 outbuf[2] = word1 & 255;
178 outbuf[3] = word1 >> 8;
179 outbuf[4] = word2 & 255;
180 outbuf[5] = word2 >> 8;
181 outbuf[6] = word3 & 255;
182 outbuf[7] = word3 >> 8;
183 }
184 }
185
186 void
187 arctwo_setkey_ekb (arctwo_context *context,
188 size_t keylen, const char *key, size_t effective_keylen)
189 {
190 size_t i;
191 uint8_t *S, x;
192
193 if (keylen < 40 / 8 || effective_keylen > 1024)
194 return;
195
196 S = (uint8_t *) context->S;
197
198 for (i = 0; i < keylen; i++)
199 S[i] = (uint8_t) key[i];
200
201 for (i = keylen; i < 128; i++)
202 S[i] = arctwo_sbox[(S[i - keylen] + S[i - 1]) & 255];
203
204 S[0] = arctwo_sbox[S[0]];
205
206
207
208
209 if (effective_keylen)
210 {
211 size_t len = (effective_keylen + 7) >> 3;
212 i = 128 - len;
213 x = arctwo_sbox[S[i] & (255 >> (7 & -effective_keylen))];
214 S[i] = x;
215
216 while (i--)
217 {
218 x = arctwo_sbox[x ^ S[i + len]];
219 S[i] = x;
220 }
221 }
222
223
224 for (i = 0; i < 64; i++)
225 context->S[i] = ((uint16_t) S[i * 2] | (((uint16_t) S[i * 2 + 1]) << 8));
226 }