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0bcb8184 MW |
1 | /* |
2 | * x448.c: Hamburg's X448 key-exchange function | |
3 | */ | |
4 | /* | |
5 | * This file is Free Software. It has been modified to as part of its | |
6 | * incorporation into secnet. | |
7 | * | |
8 | * Copyright 2017 Mark Wooding | |
9 | * | |
10 | * You may redistribute this file and/or modify it under the terms of | |
11 | * the permissive licence shown below. | |
12 | * | |
13 | * You may redistribute secnet as a whole and/or modify it under the | |
14 | * terms of the GNU General Public License as published by the Free | |
15 | * Software Foundation; either version 3, or (at your option) any | |
16 | * later version. | |
17 | * | |
18 | * This program is distributed in the hope that it will be useful, | |
19 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
20 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
21 | * GNU General Public License for more details. | |
22 | * | |
23 | * You should have received a copy of the GNU General Public License | |
24 | * along with this program; if not, see | |
25 | * https://www.gnu.org/licenses/gpl.html. | |
26 | */ | |
27 | /* | |
28 | * Imported from Catacomb, and modified for Secnet (2017-04-30): | |
29 | * | |
30 | * * Use `fake-mLib-bits.h' in place of the real <mLib/bits.h>. | |
31 | * | |
32 | * * Remove the test rig code: a replacement is in a separate source file. | |
33 | * | |
34 | * * Strip out the key-management definitions. | |
35 | * | |
36 | * The file's original comment headers are preserved below. | |
37 | */ | |
b7a5ecfc MW |
38 | /* -*-c-*- |
39 | * | |
40 | * The X448 key-agreement algorithm | |
41 | * | |
42 | * (c) 2017 Straylight/Edgeware | |
43 | */ | |
44 | ||
45 | /*----- Licensing notice --------------------------------------------------* | |
46 | * | |
47 | * This file is part of Catacomb. | |
48 | * | |
49 | * Catacomb is free software; you can redistribute it and/or modify | |
50 | * it under the terms of the GNU Library General Public License as | |
51 | * published by the Free Software Foundation; either version 2 of the | |
52 | * License, or (at your option) any later version. | |
53 | * | |
54 | * Catacomb is distributed in the hope that it will be useful, | |
55 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
56 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
57 | * GNU Library General Public License for more details. | |
58 | * | |
59 | * You should have received a copy of the GNU Library General Public | |
60 | * License along with Catacomb; if not, write to the Free | |
61 | * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, | |
62 | * MA 02111-1307, USA. | |
63 | */ | |
64 | ||
65 | /*----- Header files ------------------------------------------------------*/ | |
66 | ||
0bcb8184 | 67 | #include "fake-mLib-bits.h" |
b7a5ecfc MW |
68 | |
69 | #include "montladder.h" | |
70 | #include "fgoldi.h" | |
71 | #include "x448.h" | |
72 | ||
73 | /*----- Important constants -----------------------------------------------*/ | |
74 | ||
75 | const octet x448_base[56] = { 5, 0, /* ... */ }; | |
76 | ||
77 | #define A0 39081 | |
78 | ||
b7a5ecfc MW |
79 | /*----- Main code ---------------------------------------------------------*/ |
80 | ||
81 | /* --- @x448@ --- * | |
82 | * | |
83 | * Arguments: @octet zz[X448_OUTSZ]@ = where to put the result | |
84 | * @const octet k[X448_KEYSZ]@ = pointer to private key | |
85 | * @const octet qx[X448_PUBSZ]@ = pointer to public value | |
86 | * | |
87 | * Returns: --- | |
88 | * | |
89 | * Use: Calculates X448 of @k@ and @qx@. | |
90 | */ | |
91 | ||
92 | void x448(octet zz[X448_OUTSZ], | |
93 | const octet k[X448_KEYSZ], | |
94 | const octet qx[X448_PUBSZ]) | |
95 | { | |
96 | uint32 kw[14]; | |
97 | fgoldi x1; | |
98 | unsigned i; | |
99 | ||
100 | /* Load and clamp the key. The low bits are cleared to kill the small | |
101 | * subgroups on the curve and its twist, and a high bit is set to guard | |
102 | * against careless implementations, though this isn't one of those. | |
103 | */ | |
104 | for (i = 0; i < 14; i++) kw[i] = LOAD32_L(k + 4*i); | |
105 | kw[0] &= 0xfffffffc; kw[13] |= 0x80000000; | |
106 | ||
107 | /* And run the ladder. */ | |
108 | fgoldi_load(&x1, qx); | |
109 | #define MULA0(z, x) do { fgoldi_mulconst((z), (x), A0); } while (0) | |
110 | MONT_LADDER(fgoldi, MULA0, kw, 14, 32, &x1, &x1); | |
111 | #undef MULA0 | |
112 | fgoldi_store(zz, &x1); | |
113 | } | |
114 | ||
115 | /*----- Test rig ----------------------------------------------------------*/ | |
116 | ||
117 | #ifdef TEST_RIG | |
118 | ||
119 | #include <mLib/report.h> | |
120 | #include <mLib/str.h> | |
121 | #include <mLib/testrig.h> | |
122 | ||
123 | static int vrf_x448(dstr dv[]) | |
124 | { | |
125 | dstr dz = DSTR_INIT; | |
126 | int ok = 1; | |
127 | ||
128 | if (dv[0].len != 56) die(1, "bad key length"); | |
129 | if (dv[1].len != 56) die(1, "bad public length"); | |
130 | if (dv[2].len != 56) die(1, "bad result length"); | |
131 | ||
132 | dstr_ensure(&dz, 56); dz.len = 56; | |
133 | x448((octet *)dz.buf, | |
134 | (const octet *)dv[0].buf, | |
135 | (const octet *)dv[1].buf); | |
136 | if (memcmp(dz.buf, dv[2].buf, 56) != 0) { | |
137 | ok = 0; | |
138 | fprintf(stderr, "failed!"); | |
139 | fprintf(stderr, "\n\t k = "); type_hex.dump(&dv[0], stderr); | |
140 | fprintf(stderr, "\n\t p = "); type_hex.dump(&dv[1], stderr); | |
141 | fprintf(stderr, "\n\twant = "); type_hex.dump(&dv[2], stderr); | |
142 | fprintf(stderr, "\n\tcalc = "); type_hex.dump(&dz, stderr); | |
143 | fprintf(stderr, "\n"); | |
144 | } | |
145 | ||
146 | dstr_destroy(&dz); | |
147 | return (ok); | |
148 | } | |
149 | ||
150 | static int vrf_mct(dstr dv[]) | |
151 | { | |
152 | octet b0[56], b1[56], *k = b0, *x = b1, *t; | |
153 | unsigned long i, niter; | |
154 | dstr d = DSTR_INIT; | |
155 | int ok = 1; | |
156 | ||
157 | if (dv[0].len != sizeof(b0)) { fprintf(stderr, "k len\n"); exit(2); } | |
158 | if (dv[1].len != sizeof(b1)) { fprintf(stderr, "x len\n"); exit(2); } | |
159 | if (dv[3].len != sizeof(b0)) { fprintf(stderr, "result len\n"); exit(2); } | |
160 | memcpy(b0, dv[0].buf, sizeof(b0)); | |
161 | memcpy(b1, dv[1].buf, sizeof(b1)); | |
162 | niter = *(unsigned long *)dv[2].buf; | |
163 | dstr_ensure(&d, 56); d.len = 56; t = (octet *)d.buf; | |
164 | ||
165 | for (i = 0; i < niter; i++) { | |
166 | x448(x, k, x); | |
167 | t = x; x = k; k = t; | |
168 | } | |
169 | memcpy(d.buf, k, d.len); | |
170 | ||
171 | if (memcmp(d.buf, dv[3].buf, d.len) != 0) { | |
172 | ok = 0; | |
173 | fprintf(stderr, "failed..."); | |
174 | fprintf(stderr, "\n\tinitial k = "); type_hex.dump(&dv[0], stderr); | |
175 | fprintf(stderr, "\n\tinitial x = "); type_hex.dump(&dv[1], stderr); | |
176 | fprintf(stderr, "\n\titerations = %lu", niter); | |
177 | fprintf(stderr, "\n\texpected = "); type_hex.dump(&dv[3], stderr); | |
178 | fprintf(stderr, "\n\tcalculated = "); type_hex.dump(&d, stderr); | |
179 | fputc('\n', stderr); | |
180 | } | |
181 | ||
182 | dstr_destroy(&d); | |
183 | return (ok); | |
184 | } | |
185 | ||
186 | static test_chunk tests[] = { | |
187 | { "x448", vrf_x448, { &type_hex, &type_hex, &type_hex } }, | |
188 | { "x448-mct", vrf_mct, | |
189 | { &type_hex, &type_hex, &type_ulong, &type_hex } }, | |
190 | { 0, 0, { 0 } } | |
191 | }; | |
192 | ||
193 | int main(int argc, char *argv[]) | |
194 | { | |
195 | test_run(argc, argv, tests, SRCDIR "/t/x448"); | |
196 | return (0); | |
197 | } | |
198 | ||
199 | #endif | |
200 | ||
201 | /*----- That's all, folks -------------------------------------------------*/ |