1#include "sc.h"
2#include "crypto_int64.h"
3#include "crypto_uint32.h"
4#include "crypto_uint64.h"
5
6static crypto_uint64 load_3(const unsigned char *in)
7{
8 crypto_uint64 result;
9 result = (crypto_uint64) in[0];
10 result |= ((crypto_uint64) in[1]) << 8;
11 result |= ((crypto_uint64) in[2]) << 16;
12 return result;
13}
14
15static crypto_uint64 load_4(const unsigned char *in)
16{
17 crypto_uint64 result;
18 result = (crypto_uint64) in[0];
19 result |= ((crypto_uint64) in[1]) << 8;
20 result |= ((crypto_uint64) in[2]) << 16;
21 result |= ((crypto_uint64) in[3]) << 24;
22 return result;
23}
24
25/*
26Input:
27 a[0]+256*a[1]+...+256^31*a[31] = a
28 b[0]+256*b[1]+...+256^31*b[31] = b
29 c[0]+256*c[1]+...+256^31*c[31] = c
30
31Output:
32 s[0]+256*s[1]+...+256^31*s[31] = (ab+c) mod l
33 where l = 2^252 + 27742317777372353535851937790883648493.
34*/
35
36void sc_muladd(unsigned char *s,const unsigned char *a,const unsigned char *b,const unsigned char *c)
37{
38 crypto_int64 a0 = 2097151 & load_3(a);
39 crypto_int64 a1 = 2097151 & (load_4(a + 2) >> 5);
40 crypto_int64 a2 = 2097151 & (load_3(a + 5) >> 2);
41 crypto_int64 a3 = 2097151 & (load_4(a + 7) >> 7);
42 crypto_int64 a4 = 2097151 & (load_4(a + 10) >> 4);
43 crypto_int64 a5 = 2097151 & (load_3(a + 13) >> 1);
44 crypto_int64 a6 = 2097151 & (load_4(a + 15) >> 6);
45 crypto_int64 a7 = 2097151 & (load_3(a + 18) >> 3);
46 crypto_int64 a8 = 2097151 & load_3(a + 21);
47 crypto_int64 a9 = 2097151 & (load_4(a + 23) >> 5);
48 crypto_int64 a10 = 2097151 & (load_3(a + 26) >> 2);
49 crypto_int64 a11 = (load_4(a + 28) >> 7);
50 crypto_int64 b0 = 2097151 & load_3(b);
51 crypto_int64 b1 = 2097151 & (load_4(b + 2) >> 5);
52 crypto_int64 b2 = 2097151 & (load_3(b + 5) >> 2);
53 crypto_int64 b3 = 2097151 & (load_4(b + 7) >> 7);
54 crypto_int64 b4 = 2097151 & (load_4(b + 10) >> 4);
55 crypto_int64 b5 = 2097151 & (load_3(b + 13) >> 1);
56 crypto_int64 b6 = 2097151 & (load_4(b + 15) >> 6);
57 crypto_int64 b7 = 2097151 & (load_3(b + 18) >> 3);
58 crypto_int64 b8 = 2097151 & load_3(b + 21);
59 crypto_int64 b9 = 2097151 & (load_4(b + 23) >> 5);
60 crypto_int64 b10 = 2097151 & (load_3(b + 26) >> 2);
61 crypto_int64 b11 = (load_4(b + 28) >> 7);
62 crypto_int64 c0 = 2097151 & load_3(c);
63 crypto_int64 c1 = 2097151 & (load_4(c + 2) >> 5);
64 crypto_int64 c2 = 2097151 & (load_3(c + 5) >> 2);
65 crypto_int64 c3 = 2097151 & (load_4(c + 7) >> 7);
66 crypto_int64 c4 = 2097151 & (load_4(c + 10) >> 4);
67 crypto_int64 c5 = 2097151 & (load_3(c + 13) >> 1);
68 crypto_int64 c6 = 2097151 & (load_4(c + 15) >> 6);
69 crypto_int64 c7 = 2097151 & (load_3(c + 18) >> 3);
70 crypto_int64 c8 = 2097151 & load_3(c + 21);
71 crypto_int64 c9 = 2097151 & (load_4(c + 23) >> 5);
72 crypto_int64 c10 = 2097151 & (load_3(c + 26) >> 2);
73 crypto_int64 c11 = (load_4(c + 28) >> 7);
74 crypto_int64 s0;
75 crypto_int64 s1;
76 crypto_int64 s2;
77 crypto_int64 s3;
78 crypto_int64 s4;
79 crypto_int64 s5;
80 crypto_int64 s6;
81 crypto_int64 s7;
82 crypto_int64 s8;
83 crypto_int64 s9;
84 crypto_int64 s10;
85 crypto_int64 s11;
86 crypto_int64 s12;
87 crypto_int64 s13;
88 crypto_int64 s14;
89 crypto_int64 s15;
90 crypto_int64 s16;
91 crypto_int64 s17;
92 crypto_int64 s18;
93 crypto_int64 s19;
94 crypto_int64 s20;
95 crypto_int64 s21;
96 crypto_int64 s22;
97 crypto_int64 s23;
98 crypto_int64 carry0;
99 crypto_int64 carry1;
100 crypto_int64 carry2;
101 crypto_int64 carry3;
102 crypto_int64 carry4;
103 crypto_int64 carry5;
104 crypto_int64 carry6;
105 crypto_int64 carry7;
106 crypto_int64 carry8;
107 crypto_int64 carry9;
108 crypto_int64 carry10;
109 crypto_int64 carry11;
110 crypto_int64 carry12;
111 crypto_int64 carry13;
112 crypto_int64 carry14;
113 crypto_int64 carry15;
114 crypto_int64 carry16;
115 crypto_int64 carry17;
116 crypto_int64 carry18;
117 crypto_int64 carry19;
118 crypto_int64 carry20;
119 crypto_int64 carry21;
120 crypto_int64 carry22;
121
122 s0 = c0 + a0*b0;
123 s1 = c1 + a0*b1 + a1*b0;
124 s2 = c2 + a0*b2 + a1*b1 + a2*b0;
125 s3 = c3 + a0*b3 + a1*b2 + a2*b1 + a3*b0;
126 s4 = c4 + a0*b4 + a1*b3 + a2*b2 + a3*b1 + a4*b0;
127 s5 = c5 + a0*b5 + a1*b4 + a2*b3 + a3*b2 + a4*b1 + a5*b0;
128 s6 = c6 + a0*b6 + a1*b5 + a2*b4 + a3*b3 + a4*b2 + a5*b1 + a6*b0;
129 s7 = c7 + a0*b7 + a1*b6 + a2*b5 + a3*b4 + a4*b3 + a5*b2 + a6*b1 + a7*b0;
130 s8 = c8 + a0*b8 + a1*b7 + a2*b6 + a3*b5 + a4*b4 + a5*b3 + a6*b2 + a7*b1 + a8*b0;
131 s9 = c9 + a0*b9 + a1*b8 + a2*b7 + a3*b6 + a4*b5 + a5*b4 + a6*b3 + a7*b2 + a8*b1 + a9*b0;
132 s10 = c10 + a0*b10 + a1*b9 + a2*b8 + a3*b7 + a4*b6 + a5*b5 + a6*b4 + a7*b3 + a8*b2 + a9*b1 + a10*b0;
133 s11 = c11 + a0*b11 + a1*b10 + a2*b9 + a3*b8 + a4*b7 + a5*b6 + a6*b5 + a7*b4 + a8*b3 + a9*b2 + a10*b1 + a11*b0;
134 s12 = a1*b11 + a2*b10 + a3*b9 + a4*b8 + a5*b7 + a6*b6 + a7*b5 + a8*b4 + a9*b3 + a10*b2 + a11*b1;
135 s13 = a2*b11 + a3*b10 + a4*b9 + a5*b8 + a6*b7 + a7*b6 + a8*b5 + a9*b4 + a10*b3 + a11*b2;
136 s14 = a3*b11 + a4*b10 + a5*b9 + a6*b8 + a7*b7 + a8*b6 + a9*b5 + a10*b4 + a11*b3;
137 s15 = a4*b11 + a5*b10 + a6*b9 + a7*b8 + a8*b7 + a9*b6 + a10*b5 + a11*b4;
138 s16 = a5*b11 + a6*b10 + a7*b9 + a8*b8 + a9*b7 + a10*b6 + a11*b5;
139 s17 = a6*b11 + a7*b10 + a8*b9 + a9*b8 + a10*b7 + a11*b6;
140 s18 = a7*b11 + a8*b10 + a9*b9 + a10*b8 + a11*b7;
141 s19 = a8*b11 + a9*b10 + a10*b9 + a11*b8;
142 s20 = a9*b11 + a10*b10 + a11*b9;
143 s21 = a10*b11 + a11*b10;
144 s22 = a11*b11;
145 s23 = 0;
146
147 carry0 = (s0 + (1<<20)) >> 21; s1 += carry0; s0 -= carry0 << 21;
148 carry2 = (s2 + (1<<20)) >> 21; s3 += carry2; s2 -= carry2 << 21;
149 carry4 = (s4 + (1<<20)) >> 21; s5 += carry4; s4 -= carry4 << 21;
150 carry6 = (s6 + (1<<20)) >> 21; s7 += carry6; s6 -= carry6 << 21;
151 carry8 = (s8 + (1<<20)) >> 21; s9 += carry8; s8 -= carry8 << 21;
152 carry10 = (s10 + (1<<20)) >> 21; s11 += carry10; s10 -= carry10 << 21;
153 carry12 = (s12 + (1<<20)) >> 21; s13 += carry12; s12 -= carry12 << 21;
154 carry14 = (s14 + (1<<20)) >> 21; s15 += carry14; s14 -= carry14 << 21;
155 carry16 = (s16 + (1<<20)) >> 21; s17 += carry16; s16 -= carry16 << 21;
156 carry18 = (s18 + (1<<20)) >> 21; s19 += carry18; s18 -= carry18 << 21;
157 carry20 = (s20 + (1<<20)) >> 21; s21 += carry20; s20 -= carry20 << 21;
158 carry22 = (s22 + (1<<20)) >> 21; s23 += carry22; s22 -= carry22 << 21;
159
160 carry1 = (s1 + (1<<20)) >> 21; s2 += carry1; s1 -= carry1 << 21;
161 carry3 = (s3 + (1<<20)) >> 21; s4 += carry3; s3 -= carry3 << 21;
162 carry5 = (s5 + (1<<20)) >> 21; s6 += carry5; s5 -= carry5 << 21;
163 carry7 = (s7 + (1<<20)) >> 21; s8 += carry7; s7 -= carry7 << 21;
164 carry9 = (s9 + (1<<20)) >> 21; s10 += carry9; s9 -= carry9 << 21;
165 carry11 = (s11 + (1<<20)) >> 21; s12 += carry11; s11 -= carry11 << 21;
166 carry13 = (s13 + (1<<20)) >> 21; s14 += carry13; s13 -= carry13 << 21;
167 carry15 = (s15 + (1<<20)) >> 21; s16 += carry15; s15 -= carry15 << 21;
168 carry17 = (s17 + (1<<20)) >> 21; s18 += carry17; s17 -= carry17 << 21;
169 carry19 = (s19 + (1<<20)) >> 21; s20 += carry19; s19 -= carry19 << 21;
170 carry21 = (s21 + (1<<20)) >> 21; s22 += carry21; s21 -= carry21 << 21;
171
172 s11 += s23 * 666643;
173 s12 += s23 * 470296;
174 s13 += s23 * 654183;
175 s14 -= s23 * 997805;
176 s15 += s23 * 136657;
177 s16 -= s23 * 683901;
178 s23 = 0;
179
180 s10 += s22 * 666643;
181 s11 += s22 * 470296;
182 s12 += s22 * 654183;
183 s13 -= s22 * 997805;
184 s14 += s22 * 136657;
185 s15 -= s22 * 683901;
186 s22 = 0;
187
188 s9 += s21 * 666643;
189 s10 += s21 * 470296;
190 s11 += s21 * 654183;
191 s12 -= s21 * 997805;
192 s13 += s21 * 136657;
193 s14 -= s21 * 683901;
194 s21 = 0;
195
196 s8 += s20 * 666643;
197 s9 += s20 * 470296;
198 s10 += s20 * 654183;
199 s11 -= s20 * 997805;
200 s12 += s20 * 136657;
201 s13 -= s20 * 683901;
202 s20 = 0;
203
204 s7 += s19 * 666643;
205 s8 += s19 * 470296;
206 s9 += s19 * 654183;
207 s10 -= s19 * 997805;
208 s11 += s19 * 136657;
209 s12 -= s19 * 683901;
210 s19 = 0;
211
212 s6 += s18 * 666643;
213 s7 += s18 * 470296;
214 s8 += s18 * 654183;
215 s9 -= s18 * 997805;
216 s10 += s18 * 136657;
217 s11 -= s18 * 683901;
218 s18 = 0;
219
220 carry6 = (s6 + (1<<20)) >> 21; s7 += carry6; s6 -= carry6 << 21;
221 carry8 = (s8 + (1<<20)) >> 21; s9 += carry8; s8 -= carry8 << 21;
222 carry10 = (s10 + (1<<20)) >> 21; s11 += carry10; s10 -= carry10 << 21;
223 carry12 = (s12 + (1<<20)) >> 21; s13 += carry12; s12 -= carry12 << 21;
224 carry14 = (s14 + (1<<20)) >> 21; s15 += carry14; s14 -= carry14 << 21;
225 carry16 = (s16 + (1<<20)) >> 21; s17 += carry16; s16 -= carry16 << 21;
226
227 carry7 = (s7 + (1<<20)) >> 21; s8 += carry7; s7 -= carry7 << 21;
228 carry9 = (s9 + (1<<20)) >> 21; s10 += carry9; s9 -= carry9 << 21;
229 carry11 = (s11 + (1<<20)) >> 21; s12 += carry11; s11 -= carry11 << 21;
230 carry13 = (s13 + (1<<20)) >> 21; s14 += carry13; s13 -= carry13 << 21;
231 carry15 = (s15 + (1<<20)) >> 21; s16 += carry15; s15 -= carry15 << 21;
232
233 s5 += s17 * 666643;
234 s6 += s17 * 470296;
235 s7 += s17 * 654183;
236 s8 -= s17 * 997805;
237 s9 += s17 * 136657;
238 s10 -= s17 * 683901;
239 s17 = 0;
240
241 s4 += s16 * 666643;
242 s5 += s16 * 470296;
243 s6 += s16 * 654183;
244 s7 -= s16 * 997805;
245 s8 += s16 * 136657;
246 s9 -= s16 * 683901;
247 s16 = 0;
248
249 s3 += s15 * 666643;
250 s4 += s15 * 470296;
251 s5 += s15 * 654183;
252 s6 -= s15 * 997805;
253 s7 += s15 * 136657;
254 s8 -= s15 * 683901;
255 s15 = 0;
256
257 s2 += s14 * 666643;
258 s3 += s14 * 470296;
259 s4 += s14 * 654183;
260 s5 -= s14 * 997805;
261 s6 += s14 * 136657;
262 s7 -= s14 * 683901;
263 s14 = 0;
264
265 s1 += s13 * 666643;
266 s2 += s13 * 470296;
267 s3 += s13 * 654183;
268 s4 -= s13 * 997805;
269 s5 += s13 * 136657;
270 s6 -= s13 * 683901;
271 s13 = 0;
272
273 s0 += s12 * 666643;
274 s1 += s12 * 470296;
275 s2 += s12 * 654183;
276 s3 -= s12 * 997805;
277 s4 += s12 * 136657;
278 s5 -= s12 * 683901;
279 s12 = 0;
280
281 carry0 = (s0 + (1<<20)) >> 21; s1 += carry0; s0 -= carry0 << 21;
282 carry2 = (s2 + (1<<20)) >> 21; s3 += carry2; s2 -= carry2 << 21;
283 carry4 = (s4 + (1<<20)) >> 21; s5 += carry4; s4 -= carry4 << 21;
284 carry6 = (s6 + (1<<20)) >> 21; s7 += carry6; s6 -= carry6 << 21;
285 carry8 = (s8 + (1<<20)) >> 21; s9 += carry8; s8 -= carry8 << 21;
286 carry10 = (s10 + (1<<20)) >> 21; s11 += carry10; s10 -= carry10 << 21;
287
288 carry1 = (s1 + (1<<20)) >> 21; s2 += carry1; s1 -= carry1 << 21;
289 carry3 = (s3 + (1<<20)) >> 21; s4 += carry3; s3 -= carry3 << 21;
290 carry5 = (s5 + (1<<20)) >> 21; s6 += carry5; s5 -= carry5 << 21;
291 carry7 = (s7 + (1<<20)) >> 21; s8 += carry7; s7 -= carry7 << 21;
292 carry9 = (s9 + (1<<20)) >> 21; s10 += carry9; s9 -= carry9 << 21;
293 carry11 = (s11 + (1<<20)) >> 21; s12 += carry11; s11 -= carry11 << 21;
294
295 s0 += s12 * 666643;
296 s1 += s12 * 470296;
297 s2 += s12 * 654183;
298 s3 -= s12 * 997805;
299 s4 += s12 * 136657;
300 s5 -= s12 * 683901;
301 s12 = 0;
302
303 carry0 = s0 >> 21; s1 += carry0; s0 -= carry0 << 21;
304 carry1 = s1 >> 21; s2 += carry1; s1 -= carry1 << 21;
305 carry2 = s2 >> 21; s3 += carry2; s2 -= carry2 << 21;
306 carry3 = s3 >> 21; s4 += carry3; s3 -= carry3 << 21;
307 carry4 = s4 >> 21; s5 += carry4; s4 -= carry4 << 21;
308 carry5 = s5 >> 21; s6 += carry5; s5 -= carry5 << 21;
309 carry6 = s6 >> 21; s7 += carry6; s6 -= carry6 << 21;
310 carry7 = s7 >> 21; s8 += carry7; s7 -= carry7 << 21;
311 carry8 = s8 >> 21; s9 += carry8; s8 -= carry8 << 21;
312 carry9 = s9 >> 21; s10 += carry9; s9 -= carry9 << 21;
313 carry10 = s10 >> 21; s11 += carry10; s10 -= carry10 << 21;
314 carry11 = s11 >> 21; s12 += carry11; s11 -= carry11 << 21;
315
316 s0 += s12 * 666643;
317 s1 += s12 * 470296;
318 s2 += s12 * 654183;
319 s3 -= s12 * 997805;
320 s4 += s12 * 136657;
321 s5 -= s12 * 683901;
322 s12 = 0;
323
324 carry0 = s0 >> 21; s1 += carry0; s0 -= carry0 << 21;
325 carry1 = s1 >> 21; s2 += carry1; s1 -= carry1 << 21;
326 carry2 = s2 >> 21; s3 += carry2; s2 -= carry2 << 21;
327 carry3 = s3 >> 21; s4 += carry3; s3 -= carry3 << 21;
328 carry4 = s4 >> 21; s5 += carry4; s4 -= carry4 << 21;
329 carry5 = s5 >> 21; s6 += carry5; s5 -= carry5 << 21;
330 carry6 = s6 >> 21; s7 += carry6; s6 -= carry6 << 21;
331 carry7 = s7 >> 21; s8 += carry7; s7 -= carry7 << 21;
332 carry8 = s8 >> 21; s9 += carry8; s8 -= carry8 << 21;
333 carry9 = s9 >> 21; s10 += carry9; s9 -= carry9 << 21;
334 carry10 = s10 >> 21; s11 += carry10; s10 -= carry10 << 21;
335
336 s[0] = s0 >> 0;
337 s[1] = s0 >> 8;
338 s[2] = (s0 >> 16) | (s1 << 5);
339 s[3] = s1 >> 3;
340 s[4] = s1 >> 11;
341 s[5] = (s1 >> 19) | (s2 << 2);
342 s[6] = s2 >> 6;
343 s[7] = (s2 >> 14) | (s3 << 7);
344 s[8] = s3 >> 1;
345 s[9] = s3 >> 9;
346 s[10] = (s3 >> 17) | (s4 << 4);
347 s[11] = s4 >> 4;
348 s[12] = s4 >> 12;
349 s[13] = (s4 >> 20) | (s5 << 1);
350 s[14] = s5 >> 7;
351 s[15] = (s5 >> 15) | (s6 << 6);
352 s[16] = s6 >> 2;
353 s[17] = s6 >> 10;
354 s[18] = (s6 >> 18) | (s7 << 3);
355 s[19] = s7 >> 5;
356 s[20] = s7 >> 13;
357 s[21] = s8 >> 0;
358 s[22] = s8 >> 8;
359 s[23] = (s8 >> 16) | (s9 << 5);
360 s[24] = s9 >> 3;
361 s[25] = s9 >> 11;
362 s[26] = (s9 >> 19) | (s10 << 2);
363 s[27] = s10 >> 6;
364 s[28] = (s10 >> 14) | (s11 << 7);
365 s[29] = s11 >> 1;
366 s[30] = s11 >> 9;
367 s[31] = s11 >> 17;
368}
369