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8a7654a6 MW |
1 | /* -*-c-*- |
2 | * | |
3 | * Arithmetic in the Goldilocks field GF(2^448 - 2^224 - 1) | |
4 | * | |
5 | * (c) 2017 Straylight/Edgeware | |
6 | */ | |
7 | ||
8 | /*----- Licensing notice --------------------------------------------------* | |
9 | * | |
10 | * This file is part of secnet. | |
11 | * See README for full list of copyright holders. | |
12 | * | |
13 | * secnet is free software; you can redistribute it and/or modify it | |
14 | * under the terms of the GNU General Public License as published by | |
15 | * the Free Software Foundation; either version d of the License, or | |
16 | * (at your option) any later version. | |
17 | * | |
18 | * secnet is distributed in the hope that it will be useful, but | |
19 | * WITHOUT ANY WARRANTY; without even the implied warranty of | |
20 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
21 | * General Public License for more details. | |
22 | * | |
23 | * You should have received a copy of the GNU General Public License | |
24 | * version 3 along with secnet; if not, see | |
25 | * https://www.gnu.org/licenses/gpl.html. | |
26 | * | |
27 | * This file was originally part of Catacomb, but has been automatically | |
28 | * modified for incorporation into secnet: see `import-catacomb-crypto' | |
29 | * for details. | |
30 | * | |
31 | * Catacomb is free software; you can redistribute it and/or modify | |
32 | * it under the terms of the GNU Library General Public License as | |
33 | * published by the Free Software Foundation; either version 2 of the | |
34 | * License, or (at your option) any later version. | |
35 | * | |
36 | * Catacomb is distributed in the hope that it will be useful, | |
37 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
38 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
39 | * GNU Library General Public License for more details. | |
40 | * | |
41 | * You should have received a copy of the GNU Library General Public | |
42 | * License along with Catacomb; if not, write to the Free | |
43 | * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, | |
44 | * MA 02111-1307, USA. | |
45 | */ | |
46 | ||
47 | #ifndef CATACOMB_FGOLDI_H | |
48 | #define CATACOMB_FGOLDI_H | |
49 | ||
50 | #ifdef __cplusplus | |
51 | extern "C" { | |
52 | #endif | |
53 | ||
54 | /*----- Header files ------------------------------------------------------*/ | |
55 | ||
56 | #include "fake-mLib-bits.h" | |
57 | ||
58 | #ifndef CATACOMB_QFARITH_H | |
59 | # include "qfarith.h" | |
60 | #endif | |
61 | ||
62 | /*----- Data structures ---------------------------------------------------*/ | |
63 | ||
64 | typedef union { | |
65 | int32 p28[16]; | |
66 | } fgoldi; | |
67 | ||
68 | /*----- Functions provided ------------------------------------------------*/ | |
69 | ||
70 | /* --- @fgoldi_load@ --- * | |
71 | * | |
72 | * Arguments: @fgoldi *z@ = where to store the result | |
73 | * @const octet xv[56]@ = source to read | |
74 | * | |
75 | * Returns: --- | |
76 | * | |
77 | * Use: Reads an element of %$\gf{2^{448} - 2^{224} - 19}$% in | |
78 | * external representation from @xv@ and stores it in @z@. | |
79 | * | |
80 | * External representation is little-endian base-256. Some | |
81 | * elements have multiple encodings, which are not produced by | |
82 | * correct software; use of noncanonical encodings is not an | |
83 | * error, and toleration of them is considered a performance | |
84 | * feature. | |
85 | */ | |
86 | ||
87 | extern void fgoldi_load(fgoldi */*z*/, const octet /*xv*/[56]); | |
88 | ||
89 | /* --- @fgoldi_store@ --- * | |
90 | * | |
91 | * Arguments: @octet zv[56]@ = where to write the result | |
92 | * @const fgoldi *x@ = the field element to write | |
93 | * | |
94 | * Returns: --- | |
95 | * | |
96 | * Use: Stores a field element in the given octet vector in external | |
97 | * representation. A canonical encoding is always stored. | |
98 | */ | |
99 | ||
100 | extern void fgoldi_store(octet /*zv*/[56], const fgoldi */*x*/); | |
101 | ||
102 | /* --- @fgoldi_set@ --- * | |
103 | * | |
104 | * Arguments: @fgoldi *z@ = where to write the result | |
105 | * @int a@ = a small-ish constant | |
106 | * | |
107 | * Returns: --- | |
108 | * | |
109 | * Use: Sets @z@ to equal @a@. | |
110 | */ | |
111 | ||
112 | extern void fgoldi_set(fgoldi */*x*/, int /*a*/); | |
113 | ||
114 | /* --- @fgoldi_add@ --- * | |
115 | * | |
116 | * Arguments: @fgoldi *z@ = where to put the result (may alias @x@ or @y@) | |
117 | * @const fgoldi *x, *y@ = two operands | |
118 | * | |
119 | * Returns: --- | |
120 | * | |
121 | * Use: Set @z@ to the sum %$x + y$%. | |
122 | */ | |
123 | ||
124 | extern void fgoldi_add(fgoldi */*z*/, | |
125 | const fgoldi */*x*/, const fgoldi */*y*/); | |
126 | ||
127 | /* --- @fgoldi_sub@ --- * | |
128 | * | |
129 | * Arguments: @fgoldi *z@ = where to put the result (may alias @x@ or @y@) | |
130 | * @const fgoldi *x, *y@ = two operands | |
131 | * | |
132 | * Returns: --- | |
133 | * | |
134 | * Use: Set @z@ to the difference %$x - y$%. | |
135 | */ | |
136 | ||
137 | extern void fgoldi_sub(fgoldi */*z*/, | |
138 | const fgoldi */*x*/, const fgoldi */*y*/); | |
139 | ||
140 | /* --- @fgoldi_condswap@ --- * | |
141 | * | |
142 | * Arguments: @fgoldi *x, *y@ = two operands | |
143 | * @uint32 m@ = a mask | |
144 | * | |
145 | * Returns: --- | |
146 | * | |
147 | * Use: If @m@ is zero, do nothing; if @m@ is all-bits-set, then | |
148 | * exchange @x@ and @y@. If @m@ has some other value, then | |
149 | * scramble @x@ and @y@ in an unhelpful way. | |
150 | */ | |
151 | ||
152 | extern void fgoldi_condswap(fgoldi */*x*/, fgoldi */*y*/, uint32 /*m*/); | |
153 | ||
154 | /* --- @fgoldi_mulconst@ --- * | |
155 | * | |
156 | * Arguments: @fgoldi *z@ = where to put the result (may alias @x@) | |
157 | * @const fgoldi *x@ = an operand | |
158 | * @long a@ = a small-ish constant; %$|a| < 2^{20}$%. | |
159 | * | |
160 | * Returns: --- | |
161 | * | |
162 | * Use: Set @z@ to the product %$a x$%. | |
163 | */ | |
164 | ||
165 | extern void fgoldi_mulconst(fgoldi */*z*/, const fgoldi */*x*/, long /*a*/); | |
166 | ||
167 | /* --- @fgoldi_mul@ --- * | |
168 | * | |
169 | * Arguments: @fgoldi *z@ = where to put the result (may alias @x@ or @y@) | |
170 | * @const fgoldi *x, *y@ = two operands | |
171 | * | |
172 | * Returns: --- | |
173 | * | |
174 | * Use: Set @z@ to the product %$x y$%. | |
175 | */ | |
176 | ||
177 | extern void fgoldi_mul(fgoldi */*z*/, | |
178 | const fgoldi */*x*/, const fgoldi */*y*/); | |
179 | ||
180 | /* --- @fgoldi_sqr@ --- * | |
181 | * | |
182 | * Arguments: @fgoldi *z@ = where to put the result (may alias @x@ or @y@) | |
183 | * @const fgoldi *x@ = an operand | |
184 | * | |
185 | * Returns: --- | |
186 | * | |
187 | * Use: Set @z@ to the square %$x^2$%. | |
188 | */ | |
189 | ||
190 | extern void fgoldi_sqr(fgoldi */*z*/, const fgoldi */*x*/); | |
191 | ||
192 | /* --- @fgoldi_inv@ --- * | |
193 | * | |
194 | * Arguments: @fgoldi *z@ = where to put the result (may alias @x@) | |
195 | * @const fgoldi *x@ = an operand | |
196 | * | |
197 | * Returns: --- | |
198 | * | |
199 | * Use: Stores in @z@ the multiplicative inverse %$x^{-1}$%. If | |
200 | * %$x = 0$% then @z@ is set to zero. This is considered a | |
201 | * feature. | |
202 | */ | |
203 | ||
204 | extern void fgoldi_inv(fgoldi */*z*/, const fgoldi */*x*/); | |
205 | ||
206 | /*----- That's all, folks -------------------------------------------------*/ | |
207 | ||
208 | #ifdef __cplusplus | |
209 | } | |
210 | #endif | |
211 | ||
212 | #endif |