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1 | /* -*-c-*- |
2 | * | |
3 | * The X448 key-agreement algorithm | |
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_X448_H | |
48 | #define CATACOMB_X448_H | |
49 | ||
50 | #ifdef __cplusplus | |
51 | extern "C" { | |
52 | #endif | |
53 | ||
54 | /*----- Notes on the X448 key-agreement algorithm -------------------------* | |
55 | * | |
56 | * This is X448, as described in RFC7748, based on the elliptic curve defined | |
57 | * in Mike Hamburg, `Ed448-Goldilocks, a new elliptic curve', EUROCRYPT 2016, | |
a1a6042e MW |
58 | * https://eprint.iacr.org/2015/625/. (The curve here is 4-isogenous to |
59 | * Hamburg's curve.) | |
8a7654a6 MW |
60 | * |
61 | * The RFC-specified operation is simpler than the Diffie--Hellman function | |
62 | * described in Hamburg's paper, since it doesn't involve the `Decaf' | |
63 | * cofactor elimination procedure. Indeed, it looks very much like X25519 | |
64 | * with Hamburg's curve slotted in in place of Bernstein's. | |
65 | */ | |
66 | ||
67 | /*----- Header files ------------------------------------------------------*/ | |
68 | ||
69 | #include "fake-mLib-bits.h" | |
70 | ||
71 | /*----- Important constants -----------------------------------------------*/ | |
72 | ||
73 | #define X448_KEYSZ 56 | |
74 | #define X448_PUBSZ 56 | |
75 | #define X448_OUTSZ 56 | |
76 | ||
77 | extern const octet x448_base[56]; | |
78 | ||
79 | /*----- Functions provided ------------------------------------------------*/ | |
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 | extern void x448(octet /*zz*/[X448_OUTSZ], | |
93 | const octet /*k*/[X448_KEYSZ], | |
94 | const octet /*qx*/[X448_PUBSZ]); | |
95 | ||
96 | /*----- That's all, folks -------------------------------------------------*/ | |
97 | ||
98 | #ifdef __cplusplus | |
99 | } | |
100 | #endif | |
101 | ||
102 | #endif |