3 * The X448 key-agreement algorithm
5 * (c) 2017 Straylight/Edgeware
8 /*----- Licensing notice --------------------------------------------------*
10 * This file is part of Catacomb.
12 * Catacomb is free software; you can redistribute it and/or modify
13 * it under the terms of the GNU Library General Public License as
14 * published by the Free Software Foundation; either version 2 of the
15 * License, or (at your option) any later version.
17 * Catacomb is distributed in the hope that it will be useful,
18 * but WITHOUT ANY WARRANTY; without even the implied warranty of
19 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
20 * GNU Library General Public License for more details.
22 * You should have received a copy of the GNU Library General Public
23 * License along with Catacomb; if not, write to the Free
24 * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
28 /*----- Header files ------------------------------------------------------*/
30 #include <mLib/bits.h>
32 #include "montladder.h"
36 /*----- Important constants -----------------------------------------------*/
38 const octet x448_base
[56] = { 5, 0, /* ... */ };
42 /*----- Key fetching ------------------------------------------------------*/
44 const key_fetchdef x448_pubfetch
[] = {
45 { "pub", offsetof(x448_pub
, pub
), KENC_BINARY
, 0 },
49 static const key_fetchdef priv
[] = {
50 { "priv", offsetof(x448_priv
, priv
), KENC_BINARY
, 0 },
54 const key_fetchdef x448_privfetch
[] = {
55 { "pub", offsetof(x448_priv
, pub
), KENC_BINARY
, 0 },
56 { "private", 0, KENC_STRUCT
, priv
},
60 /*----- Main code ---------------------------------------------------------*/
64 * Arguments: @octet zz[X448_OUTSZ]@ = where to put the result
65 * @const octet k[X448_KEYSZ]@ = pointer to private key
66 * @const octet qx[X448_PUBSZ]@ = pointer to public value
70 * Use: Calculates X448 of @k@ and @qx@.
73 void x448(octet zz
[X448_OUTSZ
],
74 const octet k
[X448_KEYSZ
],
75 const octet qx
[X448_PUBSZ
])
81 /* Load and clamp the key. The low bits are cleared to kill the small
82 * subgroups on the curve and its twist, and a high bit is set to guard
83 * against careless implementations, though this isn't one of those.
85 for (i
= 0; i
< 14; i
++) kw
[i
] = LOAD32_L(k
+ 4*i
);
86 kw
[0] &= 0xfffffffc; kw
[13] |= 0x80000000;
88 /* And run the ladder. */
90 #define MULA0(z, x) do { fgoldi_mulconst((z), (x), A0); } while (0)
91 MONT_LADDER(fgoldi
, MULA0
, kw
, 14, 32, &x1
, &x1
);
93 fgoldi_store(zz
, &x1
);
96 /*----- Test rig ----------------------------------------------------------*/
100 #include <mLib/macros.h>
101 #include <mLib/report.h>
102 #include <mLib/testrig.h>
106 static int vrf_x448(dstr dv
[])
111 if (dv
[0].len
!= X448_KEYSZ
) die(1, "bad key length");
112 if (dv
[1].len
!= X448_PUBSZ
) die(1, "bad public length");
113 if (dv
[2].len
!= X448_OUTSZ
) die(1, "bad result length");
115 ct_poison(dv
[0].buf
, dv
[0].len
);
116 dstr_ensure(&dz
, X448_OUTSZ
); dz
.len
= X448_OUTSZ
;
117 x448((octet
*)dz
.buf
,
118 (const octet
*)dv
[0].buf
,
119 (const octet
*)dv
[1].buf
);
120 ct_remedy(dz
.buf
, dz
.len
);
121 if (MEMCMP(dz
.buf
, !=, dv
[2].buf
, X448_OUTSZ
)) {
123 fprintf(stderr
, "failed!");
124 fprintf(stderr
, "\n\t k = "); type_hex
.dump(&dv
[0], stderr
);
125 fprintf(stderr
, "\n\t p = "); type_hex
.dump(&dv
[1], stderr
);
126 fprintf(stderr
, "\n\twant = "); type_hex
.dump(&dv
[2], stderr
);
127 fprintf(stderr
, "\n\tcalc = "); type_hex
.dump(&dz
, stderr
);
128 fprintf(stderr
, "\n");
135 static int vrf_mct(dstr dv
[])
137 octet b0
[X448_OUTSZ
], b1
[X448_OUTSZ
], *k
= b0
, *x
= b1
, *t
;
138 unsigned long i
, niter
;
142 if (dv
[0].len
!= sizeof(b0
)) { fprintf(stderr
, "k len\n"); exit(2); }
143 if (dv
[1].len
!= sizeof(b1
)) { fprintf(stderr
, "x len\n"); exit(2); }
144 if (dv
[3].len
!= sizeof(b0
)) { fprintf(stderr
, "result len\n"); exit(2); }
145 memcpy(b0
, dv
[0].buf
, sizeof(b0
));
146 memcpy(b1
, dv
[1].buf
, sizeof(b1
));
147 niter
= *(unsigned long *)dv
[2].buf
;
148 dstr_ensure(&d
, X448_OUTSZ
); d
.len
= X448_OUTSZ
; t
= (octet
*)d
.buf
;
150 for (i
= 0; i
< niter
; i
++) {
154 memcpy(d
.buf
, k
, d
.len
);
156 if (MEMCMP(d
.buf
, !=, dv
[3].buf
, d
.len
)) {
158 fprintf(stderr
, "failed...");
159 fprintf(stderr
, "\n\tinitial k = "); type_hex
.dump(&dv
[0], stderr
);
160 fprintf(stderr
, "\n\tinitial x = "); type_hex
.dump(&dv
[1], stderr
);
161 fprintf(stderr
, "\n\titerations = %lu", niter
);
162 fprintf(stderr
, "\n\texpected = "); type_hex
.dump(&dv
[3], stderr
);
163 fprintf(stderr
, "\n\tcalculated = "); type_hex
.dump(&d
, stderr
);
171 static test_chunk tests
[] = {
172 { "x448", vrf_x448
, { &type_hex
, &type_hex
, &type_hex
} },
173 { "x448-mct", vrf_mct
,
174 { &type_hex
, &type_hex
, &type_ulong
, &type_hex
} },
178 int main(int argc
, char *argv
[])
180 test_run(argc
, argv
, tests
, SRCDIR
"/t/x448");
186 /*----- That's all, folks -------------------------------------------------*/