Mercurial > dropbear
annotate libtommath/bn_mp_n_root_ex.c @ 1671:5c8913b7464c
Mention Ed25519 in dropbearkey man (#94)
author | Vladislav Grishenko <themiron@users.noreply.github.com> |
---|---|
date | Mon, 25 May 2020 18:28:27 +0500 |
parents | f52919ffd3b1 |
children |
rev | line source |
---|---|
1655
f52919ffd3b1
update ltm to 1.1.0 and enable FIPS 186.4 compliant key-generation (#79)
Steffen Jaeckel <s_jaeckel@gmx.de>
parents:
1470
diff
changeset
|
1 #include "tommath_private.h" |
1436 | 2 #ifdef BN_MP_N_ROOT_EX_C |
3 /* LibTomMath, multiple-precision integer library -- Tom St Denis | |
4 * | |
5 * LibTomMath is a library that provides multiple-precision | |
6 * integer arithmetic as well as number theoretic functionality. | |
7 * | |
8 * The library was designed directly after the MPI library by | |
9 * Michael Fromberger but has been written from scratch with | |
10 * additional optimizations in place. | |
11 * | |
1655
f52919ffd3b1
update ltm to 1.1.0 and enable FIPS 186.4 compliant key-generation (#79)
Steffen Jaeckel <s_jaeckel@gmx.de>
parents:
1470
diff
changeset
|
12 * SPDX-License-Identifier: Unlicense |
1436 | 13 */ |
14 | |
15 /* find the n'th root of an integer | |
16 * | |
17 * Result found such that (c)**b <= a and (c+1)**b > a | |
18 * | |
19 * This algorithm uses Newton's approximation | |
20 * x[i+1] = x[i] - f(x[i])/f'(x[i]) | |
21 * which will find the root in log(N) time where | |
22 * each step involves a fair bit. This is not meant to | |
23 * find huge roots [square and cube, etc]. | |
24 */ | |
1655
f52919ffd3b1
update ltm to 1.1.0 and enable FIPS 186.4 compliant key-generation (#79)
Steffen Jaeckel <s_jaeckel@gmx.de>
parents:
1470
diff
changeset
|
25 int mp_n_root_ex(const mp_int *a, mp_digit b, mp_int *c, int fast) |
1436 | 26 { |
1655
f52919ffd3b1
update ltm to 1.1.0 and enable FIPS 186.4 compliant key-generation (#79)
Steffen Jaeckel <s_jaeckel@gmx.de>
parents:
1470
diff
changeset
|
27 mp_int t1, t2, t3, a_; |
f52919ffd3b1
update ltm to 1.1.0 and enable FIPS 186.4 compliant key-generation (#79)
Steffen Jaeckel <s_jaeckel@gmx.de>
parents:
1470
diff
changeset
|
28 int res; |
1436 | 29 |
1655
f52919ffd3b1
update ltm to 1.1.0 and enable FIPS 186.4 compliant key-generation (#79)
Steffen Jaeckel <s_jaeckel@gmx.de>
parents:
1470
diff
changeset
|
30 /* input must be positive if b is even */ |
f52919ffd3b1
update ltm to 1.1.0 and enable FIPS 186.4 compliant key-generation (#79)
Steffen Jaeckel <s_jaeckel@gmx.de>
parents:
1470
diff
changeset
|
31 if (((b & 1u) == 0u) && (a->sign == MP_NEG)) { |
f52919ffd3b1
update ltm to 1.1.0 and enable FIPS 186.4 compliant key-generation (#79)
Steffen Jaeckel <s_jaeckel@gmx.de>
parents:
1470
diff
changeset
|
32 return MP_VAL; |
f52919ffd3b1
update ltm to 1.1.0 and enable FIPS 186.4 compliant key-generation (#79)
Steffen Jaeckel <s_jaeckel@gmx.de>
parents:
1470
diff
changeset
|
33 } |
1436 | 34 |
1655
f52919ffd3b1
update ltm to 1.1.0 and enable FIPS 186.4 compliant key-generation (#79)
Steffen Jaeckel <s_jaeckel@gmx.de>
parents:
1470
diff
changeset
|
35 if ((res = mp_init(&t1)) != MP_OKAY) { |
f52919ffd3b1
update ltm to 1.1.0 and enable FIPS 186.4 compliant key-generation (#79)
Steffen Jaeckel <s_jaeckel@gmx.de>
parents:
1470
diff
changeset
|
36 return res; |
f52919ffd3b1
update ltm to 1.1.0 and enable FIPS 186.4 compliant key-generation (#79)
Steffen Jaeckel <s_jaeckel@gmx.de>
parents:
1470
diff
changeset
|
37 } |
1436 | 38 |
1655
f52919ffd3b1
update ltm to 1.1.0 and enable FIPS 186.4 compliant key-generation (#79)
Steffen Jaeckel <s_jaeckel@gmx.de>
parents:
1470
diff
changeset
|
39 if ((res = mp_init(&t2)) != MP_OKAY) { |
f52919ffd3b1
update ltm to 1.1.0 and enable FIPS 186.4 compliant key-generation (#79)
Steffen Jaeckel <s_jaeckel@gmx.de>
parents:
1470
diff
changeset
|
40 goto LBL_T1; |
f52919ffd3b1
update ltm to 1.1.0 and enable FIPS 186.4 compliant key-generation (#79)
Steffen Jaeckel <s_jaeckel@gmx.de>
parents:
1470
diff
changeset
|
41 } |
1436 | 42 |
1655
f52919ffd3b1
update ltm to 1.1.0 and enable FIPS 186.4 compliant key-generation (#79)
Steffen Jaeckel <s_jaeckel@gmx.de>
parents:
1470
diff
changeset
|
43 if ((res = mp_init(&t3)) != MP_OKAY) { |
f52919ffd3b1
update ltm to 1.1.0 and enable FIPS 186.4 compliant key-generation (#79)
Steffen Jaeckel <s_jaeckel@gmx.de>
parents:
1470
diff
changeset
|
44 goto LBL_T2; |
f52919ffd3b1
update ltm to 1.1.0 and enable FIPS 186.4 compliant key-generation (#79)
Steffen Jaeckel <s_jaeckel@gmx.de>
parents:
1470
diff
changeset
|
45 } |
1436 | 46 |
1655
f52919ffd3b1
update ltm to 1.1.0 and enable FIPS 186.4 compliant key-generation (#79)
Steffen Jaeckel <s_jaeckel@gmx.de>
parents:
1470
diff
changeset
|
47 /* if a is negative fudge the sign but keep track */ |
f52919ffd3b1
update ltm to 1.1.0 and enable FIPS 186.4 compliant key-generation (#79)
Steffen Jaeckel <s_jaeckel@gmx.de>
parents:
1470
diff
changeset
|
48 a_ = *a; |
f52919ffd3b1
update ltm to 1.1.0 and enable FIPS 186.4 compliant key-generation (#79)
Steffen Jaeckel <s_jaeckel@gmx.de>
parents:
1470
diff
changeset
|
49 a_.sign = MP_ZPOS; |
1436 | 50 |
1655
f52919ffd3b1
update ltm to 1.1.0 and enable FIPS 186.4 compliant key-generation (#79)
Steffen Jaeckel <s_jaeckel@gmx.de>
parents:
1470
diff
changeset
|
51 /* t2 = 2 */ |
f52919ffd3b1
update ltm to 1.1.0 and enable FIPS 186.4 compliant key-generation (#79)
Steffen Jaeckel <s_jaeckel@gmx.de>
parents:
1470
diff
changeset
|
52 mp_set(&t2, 2uL); |
1436 | 53 |
1655
f52919ffd3b1
update ltm to 1.1.0 and enable FIPS 186.4 compliant key-generation (#79)
Steffen Jaeckel <s_jaeckel@gmx.de>
parents:
1470
diff
changeset
|
54 do { |
f52919ffd3b1
update ltm to 1.1.0 and enable FIPS 186.4 compliant key-generation (#79)
Steffen Jaeckel <s_jaeckel@gmx.de>
parents:
1470
diff
changeset
|
55 /* t1 = t2 */ |
f52919ffd3b1
update ltm to 1.1.0 and enable FIPS 186.4 compliant key-generation (#79)
Steffen Jaeckel <s_jaeckel@gmx.de>
parents:
1470
diff
changeset
|
56 if ((res = mp_copy(&t2, &t1)) != MP_OKAY) { |
f52919ffd3b1
update ltm to 1.1.0 and enable FIPS 186.4 compliant key-generation (#79)
Steffen Jaeckel <s_jaeckel@gmx.de>
parents:
1470
diff
changeset
|
57 goto LBL_T3; |
f52919ffd3b1
update ltm to 1.1.0 and enable FIPS 186.4 compliant key-generation (#79)
Steffen Jaeckel <s_jaeckel@gmx.de>
parents:
1470
diff
changeset
|
58 } |
1436 | 59 |
1655
f52919ffd3b1
update ltm to 1.1.0 and enable FIPS 186.4 compliant key-generation (#79)
Steffen Jaeckel <s_jaeckel@gmx.de>
parents:
1470
diff
changeset
|
60 /* t2 = t1 - ((t1**b - a) / (b * t1**(b-1))) */ |
1436 | 61 |
1655
f52919ffd3b1
update ltm to 1.1.0 and enable FIPS 186.4 compliant key-generation (#79)
Steffen Jaeckel <s_jaeckel@gmx.de>
parents:
1470
diff
changeset
|
62 /* t3 = t1**(b-1) */ |
f52919ffd3b1
update ltm to 1.1.0 and enable FIPS 186.4 compliant key-generation (#79)
Steffen Jaeckel <s_jaeckel@gmx.de>
parents:
1470
diff
changeset
|
63 if ((res = mp_expt_d_ex(&t1, b - 1u, &t3, fast)) != MP_OKAY) { |
f52919ffd3b1
update ltm to 1.1.0 and enable FIPS 186.4 compliant key-generation (#79)
Steffen Jaeckel <s_jaeckel@gmx.de>
parents:
1470
diff
changeset
|
64 goto LBL_T3; |
f52919ffd3b1
update ltm to 1.1.0 and enable FIPS 186.4 compliant key-generation (#79)
Steffen Jaeckel <s_jaeckel@gmx.de>
parents:
1470
diff
changeset
|
65 } |
1436 | 66 |
1655
f52919ffd3b1
update ltm to 1.1.0 and enable FIPS 186.4 compliant key-generation (#79)
Steffen Jaeckel <s_jaeckel@gmx.de>
parents:
1470
diff
changeset
|
67 /* numerator */ |
f52919ffd3b1
update ltm to 1.1.0 and enable FIPS 186.4 compliant key-generation (#79)
Steffen Jaeckel <s_jaeckel@gmx.de>
parents:
1470
diff
changeset
|
68 /* t2 = t1**b */ |
f52919ffd3b1
update ltm to 1.1.0 and enable FIPS 186.4 compliant key-generation (#79)
Steffen Jaeckel <s_jaeckel@gmx.de>
parents:
1470
diff
changeset
|
69 if ((res = mp_mul(&t3, &t1, &t2)) != MP_OKAY) { |
1436 | 70 goto LBL_T3; |
71 } | |
1655
f52919ffd3b1
update ltm to 1.1.0 and enable FIPS 186.4 compliant key-generation (#79)
Steffen Jaeckel <s_jaeckel@gmx.de>
parents:
1470
diff
changeset
|
72 |
f52919ffd3b1
update ltm to 1.1.0 and enable FIPS 186.4 compliant key-generation (#79)
Steffen Jaeckel <s_jaeckel@gmx.de>
parents:
1470
diff
changeset
|
73 /* t2 = t1**b - a */ |
f52919ffd3b1
update ltm to 1.1.0 and enable FIPS 186.4 compliant key-generation (#79)
Steffen Jaeckel <s_jaeckel@gmx.de>
parents:
1470
diff
changeset
|
74 if ((res = mp_sub(&t2, &a_, &t2)) != MP_OKAY) { |
f52919ffd3b1
update ltm to 1.1.0 and enable FIPS 186.4 compliant key-generation (#79)
Steffen Jaeckel <s_jaeckel@gmx.de>
parents:
1470
diff
changeset
|
75 goto LBL_T3; |
f52919ffd3b1
update ltm to 1.1.0 and enable FIPS 186.4 compliant key-generation (#79)
Steffen Jaeckel <s_jaeckel@gmx.de>
parents:
1470
diff
changeset
|
76 } |
1436 | 77 |
1655
f52919ffd3b1
update ltm to 1.1.0 and enable FIPS 186.4 compliant key-generation (#79)
Steffen Jaeckel <s_jaeckel@gmx.de>
parents:
1470
diff
changeset
|
78 /* denominator */ |
f52919ffd3b1
update ltm to 1.1.0 and enable FIPS 186.4 compliant key-generation (#79)
Steffen Jaeckel <s_jaeckel@gmx.de>
parents:
1470
diff
changeset
|
79 /* t3 = t1**(b-1) * b */ |
f52919ffd3b1
update ltm to 1.1.0 and enable FIPS 186.4 compliant key-generation (#79)
Steffen Jaeckel <s_jaeckel@gmx.de>
parents:
1470
diff
changeset
|
80 if ((res = mp_mul_d(&t3, b, &t3)) != MP_OKAY) { |
f52919ffd3b1
update ltm to 1.1.0 and enable FIPS 186.4 compliant key-generation (#79)
Steffen Jaeckel <s_jaeckel@gmx.de>
parents:
1470
diff
changeset
|
81 goto LBL_T3; |
f52919ffd3b1
update ltm to 1.1.0 and enable FIPS 186.4 compliant key-generation (#79)
Steffen Jaeckel <s_jaeckel@gmx.de>
parents:
1470
diff
changeset
|
82 } |
f52919ffd3b1
update ltm to 1.1.0 and enable FIPS 186.4 compliant key-generation (#79)
Steffen Jaeckel <s_jaeckel@gmx.de>
parents:
1470
diff
changeset
|
83 |
f52919ffd3b1
update ltm to 1.1.0 and enable FIPS 186.4 compliant key-generation (#79)
Steffen Jaeckel <s_jaeckel@gmx.de>
parents:
1470
diff
changeset
|
84 /* t3 = (t1**b - a)/(b * t1**(b-1)) */ |
f52919ffd3b1
update ltm to 1.1.0 and enable FIPS 186.4 compliant key-generation (#79)
Steffen Jaeckel <s_jaeckel@gmx.de>
parents:
1470
diff
changeset
|
85 if ((res = mp_div(&t2, &t3, &t3, NULL)) != MP_OKAY) { |
f52919ffd3b1
update ltm to 1.1.0 and enable FIPS 186.4 compliant key-generation (#79)
Steffen Jaeckel <s_jaeckel@gmx.de>
parents:
1470
diff
changeset
|
86 goto LBL_T3; |
f52919ffd3b1
update ltm to 1.1.0 and enable FIPS 186.4 compliant key-generation (#79)
Steffen Jaeckel <s_jaeckel@gmx.de>
parents:
1470
diff
changeset
|
87 } |
f52919ffd3b1
update ltm to 1.1.0 and enable FIPS 186.4 compliant key-generation (#79)
Steffen Jaeckel <s_jaeckel@gmx.de>
parents:
1470
diff
changeset
|
88 |
f52919ffd3b1
update ltm to 1.1.0 and enable FIPS 186.4 compliant key-generation (#79)
Steffen Jaeckel <s_jaeckel@gmx.de>
parents:
1470
diff
changeset
|
89 if ((res = mp_sub(&t1, &t3, &t2)) != MP_OKAY) { |
f52919ffd3b1
update ltm to 1.1.0 and enable FIPS 186.4 compliant key-generation (#79)
Steffen Jaeckel <s_jaeckel@gmx.de>
parents:
1470
diff
changeset
|
90 goto LBL_T3; |
f52919ffd3b1
update ltm to 1.1.0 and enable FIPS 186.4 compliant key-generation (#79)
Steffen Jaeckel <s_jaeckel@gmx.de>
parents:
1470
diff
changeset
|
91 } |
f52919ffd3b1
update ltm to 1.1.0 and enable FIPS 186.4 compliant key-generation (#79)
Steffen Jaeckel <s_jaeckel@gmx.de>
parents:
1470
diff
changeset
|
92 } while (mp_cmp(&t1, &t2) != MP_EQ); |
1436 | 93 |
1655
f52919ffd3b1
update ltm to 1.1.0 and enable FIPS 186.4 compliant key-generation (#79)
Steffen Jaeckel <s_jaeckel@gmx.de>
parents:
1470
diff
changeset
|
94 /* result can be off by a few so check */ |
f52919ffd3b1
update ltm to 1.1.0 and enable FIPS 186.4 compliant key-generation (#79)
Steffen Jaeckel <s_jaeckel@gmx.de>
parents:
1470
diff
changeset
|
95 for (;;) { |
f52919ffd3b1
update ltm to 1.1.0 and enable FIPS 186.4 compliant key-generation (#79)
Steffen Jaeckel <s_jaeckel@gmx.de>
parents:
1470
diff
changeset
|
96 if ((res = mp_expt_d_ex(&t1, b, &t2, fast)) != MP_OKAY) { |
f52919ffd3b1
update ltm to 1.1.0 and enable FIPS 186.4 compliant key-generation (#79)
Steffen Jaeckel <s_jaeckel@gmx.de>
parents:
1470
diff
changeset
|
97 goto LBL_T3; |
f52919ffd3b1
update ltm to 1.1.0 and enable FIPS 186.4 compliant key-generation (#79)
Steffen Jaeckel <s_jaeckel@gmx.de>
parents:
1470
diff
changeset
|
98 } |
1436 | 99 |
1655
f52919ffd3b1
update ltm to 1.1.0 and enable FIPS 186.4 compliant key-generation (#79)
Steffen Jaeckel <s_jaeckel@gmx.de>
parents:
1470
diff
changeset
|
100 if (mp_cmp(&t2, &a_) == MP_GT) { |
f52919ffd3b1
update ltm to 1.1.0 and enable FIPS 186.4 compliant key-generation (#79)
Steffen Jaeckel <s_jaeckel@gmx.de>
parents:
1470
diff
changeset
|
101 if ((res = mp_sub_d(&t1, 1uL, &t1)) != MP_OKAY) { |
f52919ffd3b1
update ltm to 1.1.0 and enable FIPS 186.4 compliant key-generation (#79)
Steffen Jaeckel <s_jaeckel@gmx.de>
parents:
1470
diff
changeset
|
102 goto LBL_T3; |
f52919ffd3b1
update ltm to 1.1.0 and enable FIPS 186.4 compliant key-generation (#79)
Steffen Jaeckel <s_jaeckel@gmx.de>
parents:
1470
diff
changeset
|
103 } |
f52919ffd3b1
update ltm to 1.1.0 and enable FIPS 186.4 compliant key-generation (#79)
Steffen Jaeckel <s_jaeckel@gmx.de>
parents:
1470
diff
changeset
|
104 } else { |
f52919ffd3b1
update ltm to 1.1.0 and enable FIPS 186.4 compliant key-generation (#79)
Steffen Jaeckel <s_jaeckel@gmx.de>
parents:
1470
diff
changeset
|
105 break; |
f52919ffd3b1
update ltm to 1.1.0 and enable FIPS 186.4 compliant key-generation (#79)
Steffen Jaeckel <s_jaeckel@gmx.de>
parents:
1470
diff
changeset
|
106 } |
f52919ffd3b1
update ltm to 1.1.0 and enable FIPS 186.4 compliant key-generation (#79)
Steffen Jaeckel <s_jaeckel@gmx.de>
parents:
1470
diff
changeset
|
107 } |
1436 | 108 |
1655
f52919ffd3b1
update ltm to 1.1.0 and enable FIPS 186.4 compliant key-generation (#79)
Steffen Jaeckel <s_jaeckel@gmx.de>
parents:
1470
diff
changeset
|
109 /* set the result */ |
f52919ffd3b1
update ltm to 1.1.0 and enable FIPS 186.4 compliant key-generation (#79)
Steffen Jaeckel <s_jaeckel@gmx.de>
parents:
1470
diff
changeset
|
110 mp_exch(&t1, c); |
f52919ffd3b1
update ltm to 1.1.0 and enable FIPS 186.4 compliant key-generation (#79)
Steffen Jaeckel <s_jaeckel@gmx.de>
parents:
1470
diff
changeset
|
111 |
f52919ffd3b1
update ltm to 1.1.0 and enable FIPS 186.4 compliant key-generation (#79)
Steffen Jaeckel <s_jaeckel@gmx.de>
parents:
1470
diff
changeset
|
112 /* set the sign of the result */ |
f52919ffd3b1
update ltm to 1.1.0 and enable FIPS 186.4 compliant key-generation (#79)
Steffen Jaeckel <s_jaeckel@gmx.de>
parents:
1470
diff
changeset
|
113 c->sign = a->sign; |
f52919ffd3b1
update ltm to 1.1.0 and enable FIPS 186.4 compliant key-generation (#79)
Steffen Jaeckel <s_jaeckel@gmx.de>
parents:
1470
diff
changeset
|
114 |
f52919ffd3b1
update ltm to 1.1.0 and enable FIPS 186.4 compliant key-generation (#79)
Steffen Jaeckel <s_jaeckel@gmx.de>
parents:
1470
diff
changeset
|
115 res = MP_OKAY; |
1436 | 116 |
1655
f52919ffd3b1
update ltm to 1.1.0 and enable FIPS 186.4 compliant key-generation (#79)
Steffen Jaeckel <s_jaeckel@gmx.de>
parents:
1470
diff
changeset
|
117 LBL_T3: |
f52919ffd3b1
update ltm to 1.1.0 and enable FIPS 186.4 compliant key-generation (#79)
Steffen Jaeckel <s_jaeckel@gmx.de>
parents:
1470
diff
changeset
|
118 mp_clear(&t3); |
f52919ffd3b1
update ltm to 1.1.0 and enable FIPS 186.4 compliant key-generation (#79)
Steffen Jaeckel <s_jaeckel@gmx.de>
parents:
1470
diff
changeset
|
119 LBL_T2: |
f52919ffd3b1
update ltm to 1.1.0 and enable FIPS 186.4 compliant key-generation (#79)
Steffen Jaeckel <s_jaeckel@gmx.de>
parents:
1470
diff
changeset
|
120 mp_clear(&t2); |
f52919ffd3b1
update ltm to 1.1.0 and enable FIPS 186.4 compliant key-generation (#79)
Steffen Jaeckel <s_jaeckel@gmx.de>
parents:
1470
diff
changeset
|
121 LBL_T1: |
f52919ffd3b1
update ltm to 1.1.0 and enable FIPS 186.4 compliant key-generation (#79)
Steffen Jaeckel <s_jaeckel@gmx.de>
parents:
1470
diff
changeset
|
122 mp_clear(&t1); |
f52919ffd3b1
update ltm to 1.1.0 and enable FIPS 186.4 compliant key-generation (#79)
Steffen Jaeckel <s_jaeckel@gmx.de>
parents:
1470
diff
changeset
|
123 return res; |
1436 | 124 } |
125 #endif | |
126 | |
1655
f52919ffd3b1
update ltm to 1.1.0 and enable FIPS 186.4 compliant key-generation (#79)
Steffen Jaeckel <s_jaeckel@gmx.de>
parents:
1470
diff
changeset
|
127 /* ref: HEAD -> master, tag: v1.1.0 */ |
f52919ffd3b1
update ltm to 1.1.0 and enable FIPS 186.4 compliant key-generation (#79)
Steffen Jaeckel <s_jaeckel@gmx.de>
parents:
1470
diff
changeset
|
128 /* git commit: 08549ad6bc8b0cede0b357a9c341c5c6473a9c55 */ |
f52919ffd3b1
update ltm to 1.1.0 and enable FIPS 186.4 compliant key-generation (#79)
Steffen Jaeckel <s_jaeckel@gmx.de>
parents:
1470
diff
changeset
|
129 /* commit time: 2019-01-28 20:32:32 +0100 */ |